
Ethereum represents the gateway to a worldwide, decentralized computing paradigm. This platform enables you to run decentralized applications (DApps) and smart contracts that have no central points of failure or control, integrate with a payment network, and operate on an open blockchain. With this practical guide, Andreas M. Antonopoulos and Gavin Wood provide everything you need to know about building smart contracts and DApps on Ethereum and other virtual-machine blockchains.

Discover why IBM, Microsoft, NASDAQ, and hundreds of other organizations are experimenting with Ethereum. This essential guide shows you how to develop the skills necessary to be an innovator in this growing and exciting new industry.

A guide to the operation and use of Ethereum and other EVM-compatible blockchains.

Mastering Ethereum


The story of the idealists, technologists, and opportunists fighting to bring cryptocurrency to the masses.

In their short history, Bitcoin and other cryptocurrencies have gone through booms, busts, and internecine wars, recently reaching a market valuation of more than $2 trillion. The central promise of crypto endures—vast fortunes made from decentralized networks not controlled by any single entity and not yet regulated by many governments.

The recent growth of crypto would have been all but impossible if not for a brilliant young man named Vitalik Buterin and his creation: Ethereum. In this book, Laura Shin takes readers inside the founding of this novel cryptocurrency network, which enabled users to launch their own new coins, thus creating a new crypto fever. She introduces readers to larger-than-life characters like Buterin, the Web3 wunderkind; his short-lived CEO, Charles Hoskinson; and Joe Lubin, a former Goldman Sachs VP who became one of crypto’s most well-known billionaires. Sparks fly as these outsized personalities fight for their piece of a seemingly limitless new business opportunity.

This fascinating book shows the crypto market for what it really is: a deeply personal struggle to influence the coming revolution in money, culture, and power.

Idealism, Greed, Lies, and the Making of the First Big Cryptocurrency Craze

The Cryptopians


Tokens - often referred to as cryptocurrencies - can represent anything from an asset to an access right, such as gold, diamonds, a fraction of a Picasso painting or an entry ticket to a concert. Tokens could also be used to reward social media contributions, incentivize the reduction of CO2 emissions, or even ones attention for watching an ad. While it has become easy to create a token, which is collectively managed by a public Web3 infrastructure like a blockchain network, the understanding of how to apply these tokens is still vague.

The industry keeps referring to “Blockchain” as different from “Bitcoin,” creating an artificial divide that is often misleading. There seems to be too little understanding about the fact that Bitcoin is a blockchain network, which is (a) globally managed by people who mostly do not know each other, and (b) enabled by the consensus protocol that (c) incentivizes all network actors for their contributions with a native token. The governance rules are tied to the minting of a native blockchain token. The Bitcoin token can, therefore, be seen as the currency of a distributed Internet tribe, called the Bitcoin network, where network actors are rewarded with Bitcoins, just as the Ether is the currency of the distributed Internet tribe Ethereum network, or Sia is the native currency of the Sia network. The Bitcoin network and other distributed ledgers all represent a collectively maintained public infrastructure and are the backbone of the next generation Internet, what the crypto community refers to as the Web3.

This book attempts to summarize existing knowledge about blockchain networks and other distributed ledgers as the backbone of the Web3, and contextualize the socio-economic implications of the Web3 applications such as smart contracts, tokens, and DAOs to the concepts of money, economics, governance and decentralized finance (DeFi).

Token Economy


Learn to Code Blockchain DApps By Building Simple Games

CryptoZombies is an interactive school that teaches you all things technical about blockchains. Learn to make smart contracts in Solidity or Libra by making your own crypto-collectibles game.

#1 Solidity Tutorial & Ethereum Blockchain Programming Course

CryptoZombies


Node Guardians is a gamified educational platform that creates lore-rich programming challenges for experienced Solidity, Huff, Cairo and Noir developers. Think of it as a skill-based RPG where developers can become familiar with specific stack components and a place where they can showcase their abilities. 

### Skills Upgrade

We have created a series of coding challenges called “quests” to engage smart contract developers, providing them with the knowledge to build safe and gas efficient applications. In addition to practical skills, we also provide theoretical knowledge about crypto history, technology and economics through building a library of articles that break down complex concepts of distributed systems & decentralized finance.


### Public Good

Node Guardians is a public good for developers and will always remain so. 
In addition to supporting the growth of cool ecosystems, we plan to make the platform sustainable by managing [infrastructure](https://infra.nodeguardians.io/) across various networks.

Rewarding non-contributing operators wastes funds, we prefer community-building and education.


Node Guardians is a gamified educational platform that creates lore-rich programming challenges for experienced Solidity, Cairo, Huff and Noir developers.

Node Guardians


Speed Run Ethereum aims to provide a structured learning path for onboarding developers to Ethereum.

Ethereum Dev Speed Run with a framework for submitting challenges, get feedback from ethereum builders, and in the process unlocking new challenges and proof of completion.

Speedrun Ethereum

Teaching the next generation of smart contract developers and auditors. Learn from industry-leading experts how to build the next generation of web3 applications and level up your career.


Level up your web3 career through industry leading comprehensive courses

Cyfrin Updraft


This is an initiative for the early solidity developers by those who were early developers sometime.

In this approach, we are looking to categorize the smart contract according to the difficulty level in multiple standards. For now, we are keeping the standard 0 to 5(can be discussed).

This initiative needs great support from Blockchain enthusiast, developer and researchers to build this school in a way which can attract learners and provide them ease for development.

First place for early developers to learn Solidity 

solidity-school


## Introductory Modules

- What is a SNARK?
- Building a SNARK (part 1)
- Building a SNARK (part 2)

## Whiteboard Sessions with ZK Projects​

- SNARKs vs. STARKS with Brendan and Bobbin
- PLONK and Custom Gates with Adrian Hamelink
- Lookup Arguments for Performance Optimisation with Mary Maller
- Zero Knowledge Virtual Machine (zkVM) with grjte
- Achieving Decentralised Private Computation with Pratyush Mishra
- Introduction to zkRollups with Barry Whitehat
- zkEVM with Jordi Baylina
- ZK Swaps with Henry de Valence
- zkID with Oleksandr Brezhniev
- Fast Recursion with Plonky2 with William Borgeaud

ZK Whiteboard Sessions is an educational series on all things zero knowledge

ZK Whiteboard Sessions


## What is a smart contract?

Smart contracts are the backbone of decentralized applications (DApps) and Web3. A smart contract is a simple program that lives on a blockchain network (such as Ethereum). They're actually not that smart. And nothing like a (legal) contract. They’re more like an executable piece of code that requires input or an trigger from an external source. They can validate those input conditions and if correct, execute their own logic to update the state on a blockchain.

## Benefits

They often serve the following purposes:
- Store and maintain data
- Manage relationships with users, or other contracts

Benefits of smart contracts are
- Immutable - once deployed none can change them
- Composable - they’re public and anyone can interact with them, or build on top of them. Much like public APIs

## Resources

The following resources have been the most popular resources on the site for a long time. These are all highly recommend to start learning about Solidity


### 1. Official Solidity website
The most obvious resources is ofcourse the official website and documentation of the Solidity team itself. The Solidity team covers all the core concepts and fundamentals of Solidity and smart contracts in general. Highly recommended

https://soliditylang.org/


### 2. Solidity by Example
The second one on the list is Solidity by Example. A great collection of more practical examples, incl. source code and supporting videos.

https://solidity-by-example.org/


### 3. CryptoZombies 
CryptoZombies is an interactive school that teaches you all things technical about blockchains. A fun and interactive way to write smart contracts in Solidity by making your own crypto-collectibles game.

https://cryptozombies.io/


### 4. Speedrun Ethereum

Speedrun Ethereum helps you get to the next level. It teaches you how to build on Ethereum; the superpowers and the gotchas while you build up your Web3 portfolio. If you like this, also make sure to check out the other work of the amazing [Austin Griffith](https://twitter.com/austingriffith) such as [ETH-build](https://eth.build/) and [Scaffold-eth](https://scaffoldeth.io/).

https://speedrunethereum.com/


### 5. Smart Contract Best Practices 

Smart contracts are complex instruments that have the authority to allocate high-value resources between complex systems. Often working autonomously. With huge financial loss at risk. This makes them critical components in these systems. Development of such components requires thoughtful design, solid engineering practices, rigorous testing and a strong security mindset. This document provides a baseline knowledge of security considerations.

https://consensys.github.io/smart-contract-best-practices/


## Other resources

If you'd like to read more, make sure to checkout all the other [Solidity](/tags/smart%20contracts) resources on the site.

Solidity is a programming language designed for developing smart contracts that run on Ethereum. It's the most in demand skill in the Web3 space. These are the best resources to help you learn more about it.

Best resources to learn Solidity


Navigating conversations and understanding key concepts in web3 sometimes requires its own terminology. In this regard, web3 is not just a technological shift, but also a cultural one.

This guide will provide you with the **most essential terms** to decode the language and become a web3 citizen. It is tailored to provide you with clear and concise definitions for the unique terms that define this industry.

Dive in, discover, and enhance your fluency in the unique lexicon of the web3 industry. (-:

If you want to contribute to the glossary, [have a look on Github](https://github.com/wslyvh/useWeb3/tree/main).

## Glossary a-z

- **Airdrop**  
  Distribution of free tokens, usually to promote a product or incentivise early users

- **Altcoin**  
  Alternative coin, any cryptocurrency other than Bitcoin

- **AMM**  
  Automated Market Maker, popular mechanism among decentralized exchanges (DEXes) involving liquidity pools instead of an orderbook-based system

- **Anon**  
  Anonymous, entity that wishes to remain anonymous or pseudonymous

- **Beacon Chain**  
  Ethereum’s proof-of-stake (PoS) consensus layer

- **Bridge**  
  Service that transfers tokens between multiple blockchains (cross-chain)

- **BUIDL**  
  Term to describe the web3 building ethos, even despite a bear market, inspired by HODL

- **CeFi**  
  Centralized finance, the “traditional” finance sector, in contrast to DeFi (decentralized finance)

- **CEX**  
  Centralized Exchange, app for swapping tokens run by a company, often used for fiat exchange; in contrast to DEX (Decentralized Exchange)

- **Cypherpunks**  
  Cypher + punks, movement originating in the early 90s, emphasizing the need for privacy in the digital age, enforced by cryptography

- **DAO**  
  Decentralized Autonomous Organization, blockchain-based organizations that are owned and governed by their members via tokens

- **DApp**  
  Decentralized Application, blockchain-based services that use smart contracts in their backend and thus have a distributed nature, without the need for intermediaries

- **DeFi**  
  Decentralized Finance, general term for decentralized services in the financial sector, that are permissionless and globally available, e.g., DEXes (decentralized exchanges) or lending protocols

- **Degen**  
  Degenerate, term for a person that is deeply involved in crypto or a specific sector, e.g., DeFi Degens

- **DEX**  
  Decentralized Exchange, blockchain-based app for swapping tokens that use smart contracts to be permissionless

- **Diamond Hands**  
  Holding a digital asset through very volatile times

- **DYOR**  
  Do Your Own Research, principle of self-verification instead of trusting others

- **EIP**  
  Ethereum Improvement Proposal, a process to describe standards for the Ethereum platform

- **ERC**  
  Ethereum Request for Comments, form of EIP to specify application layer standards; the most popular ones are ERC20 for fungible tokens and ERC721 for non-fungible tokens

- **EVM**  
  Ethereum Virtual Machine, the environment in which all Ethereum accounts and smart contracts live, the EVM defines the rules for computing a new valid state from block to block

- **Exchange**  
  An application that allows users to buy and sell crypto assets

- **Exit Scam**  
  Scenario in which a project or a part of a team steals the investors’ money and leaves

- **Explorer**  
  Webpage that displays information about the transaction history of a blockchain

- **Faucet**  
  Service that dispenses free tokens, usually for test networks

- **Flippening**  
  Term to describe a pivotal change in price or perception, e.g., when the market cap of a token exceeds the one of another token

- **FOMO**  
  Fear Of Missing Out, term to describe the feeling of not being included in something, e.g., a crypto investment or news

- **Fork**  
  Split of a blockchain or project due to technical issues or a dispute

- **FUD**  
  Fear, Uncertainty and Doubt, the opposite of FOMO

- **Gas**  
  Term for the fee that Ethereum transactions cost; it is used to reward validators and prevents malicious use of the blockchain

- **Genesis Block**  
  The first block recorded in a blockchain

- **Gm**  
  Good morning, form of greetings in crypto communities; due to the global nature of web3 it can be used at any time of the day

- **Hash**  
  Function that can be used to map data of arbitrary size to fixed-size values, e.g., for encryption, cryptographic hash functions are used in many parts of the web3 industry

- **HODL**  
  A frequent term referring to a strict buy-and-hold strategy, became famous after a misspelling in the bitcointalk forum in 2013

- **ICO**  
  Initial coin offering, the process of selling tokens when launching a new crypto project, inspired by the initial public offering (IPO) for stocks.

- **JOMO**  
  Joy Of Missing Out, converting FOMO into a positive feeling

- **KYC**  
  Know Your Customer, a process to verify the identity of customers; often used by centralized exchanges or entities

- **Layer 1**  
  Base blockchain architecture that serves as the foundation for other layers, also called mainnet, e.g., Ethereum

- **Layer 2**  
  Built on top of layer 1, usually for scaling purposes, e.g., Optimism

- **Minting**  
  Process of creating new token(s)

- **Mixer**  
  Decentralized Application that “mixes” tokens to cover their transaction history, used for private transactions

- **NFT**  
  Non-Fungible Token, a type of token that is not interchangeable or divisible, in contrast to fungible tokens; often used for digital collectibles

- **Node**  
  An instance holding a copy of the blockchain, it is connected to other nodes, synchronizing the blockchain and thus forming the network

- **OG**  
  Original Gangster, a person who was very early involved in crypto or a specific project

- **Oracle**  
  Data bridge to bring real-world information onto the blockchain

- **P2P**  
  Peer-to-peer, referring to a transaction between two people without other (central) parties involved

- **Rollups**  
  Popular type of layer 2, scaling solution that uses transaction bundling (“rolling up”) transactions before publishing them to the main chain

- **Rug Pull**  
  Scenario in which a team abandons a project and/or removes its liquidity, similar to exit scams

- **SBTs**  
  Soul-Bound-token, type of NFT that is non-transferrable

- **Smart contract**  
  Programs that run on the blockchain that follow the "if this then that" logic, they execute themselves when certain conditions are met

- **Snapshot**  
  Record of a blockchain at a particular block height, also the name of a popular DAO voting tool

- **Solidity**  
  Smart Contract Programming Language, created for the Ethereum blockchain but popular for other chains as well

- **Stablecoin**  
  A cryptocurrency that is pegged to another asset, mostly USD

- **Staking**  
  Process of locking tokens to contribute to validation in a proof of stake blockchain

- **Token**  
  Representation of a digital asset on a blockchain

- **TVL**  
  Total Value Locked, equivalent of USD locked in a blockchain or protocol, often used as an indicator in DeFi, e.g. in lending protocols

- **Validator**  
  Virtual entity participating in the consensus of a proof of stake blockchain, they participate in producing blocks and validating transactions

- **WAGMI**  
  Acronym for “We're All Gonna Make It”, expression used to show an optimistic attitude about the future of web3

- **Whale**  
  An entity holding a large amount of cryptocurrency, sometimes even a significant part of a project

- **Whitepaper**  
  Document that is released with new crypto projects to explain the details of the project.

- **ZKP**  
  Zero-Knowledge-Proof, cryptographic mechanism to verify an information without revealing it, often used for scaling solutions of privacy applications


The glossary provides you with definitions for the most important terms to navigate the web3 landscape.

Crypto glossary – important terms to navigate web3


This handbook is for people who are interested in exploring the vision behind “Web3”, and who wish to acquire in-demand skills that are essential to realizing that vision.  

A Handbook for Smart Contract Development

Learn Solidity


Create Eth App supports multiple frontend frameworks. It comes with a host of decentralized finance templates pre-filled with contract ABIs, addresses and subgraphs. Everything you need to build a modern Ethereum-powered single-page app.

- Learning how to write Ethereum-powered apps in a comfortable and feature-rich development environment.
- Starting new Ethereum-powered single-page React applications without wasting time on copy-pasting boilerplates
- Creating examples with React for your Ethereum-related libraries and components.

Create Ethereum-powered apps with one command

Create Eth App


**Features**
- Next.js
- Ethereum
- Typescript
- Chakra UI
- Wagmi
- Connectkit
- Ethers.js

An open-source Next.js + Ethereum starter kit to quickly ship Web3 Apps

Nexth Starter kit


Everything you need to build on Ethereum!

Quickly experiment with Solidity using a frontend that adapts to your smart contract

Forkable Ethereum dev stack focused on fast product iterations

Scaffold-ETH


Becoming a blockchain engineer is the most fun, rewarding, and exhilarating choice I’ve and my colleagues have ever made. And we’ve already blazed the trail for you to get started! In this article, we will show you exactly how to learn to become a blockchain engineer, from beginner to professional.

Spoiler alert, here is the exact blueprint we are going to cover to get you to a successful blockchain engineer:

1. Understand why you should become a blockchain engineer
2. Take a Blockchain Course
3. Join a Hackathon, the Community, & Build
4. Start your own protocol, Take a job, Freelance & Contribute

If you make it this far, you’ve done it! Although, I’ll add a bonus step 5 that we will talk about soon.

5. You’ve made it! Keep learning!

That’s it! These are the exact steps you need to take to become a blockchain engineer!

Become a blockchain, solidity, and smart contract engineer by following these steps

Become a Blockchain Engineer


Odds are you’ve heard about the Ethereum blockchain, whether or not you know what it is. It’s been in the news a lot lately, including the cover of some major magazines, but reading those articles can be like gibberish if you don’t have a foundation for what exactly Ethereum is. So what is it? In essence, a public database that keeps a permanent record of digital transactions. Importantly, this database doesn’t require any central authority to maintain and secure it. Instead it operates as a “trustless” transactional system — a framework in which individuals can make peer-to-peer transactions without needing to trust a third party OR one another.

Still confused? That’s where this post comes in. My aim is to explain how Ethereum functions at a technical level, without complex math or scary-looking formulas. Even if you’re not a programmer, I hope you’ll walk away with at least better grasp of the tech. If some parts are too technical and difficult to grok, that’s totally fine! There’s really no need to understand every little detail. I recommend just focusing on understanding things at a broad level.

Many of the topics covered in this post are a breakdown of the concepts discussed in the yellow paper. I’ve added my own explanations and diagrams to make understanding Ethereum easier. Those brave enough to take on the technical challenge can also read the Ethereum yellow paper.

Many of the topics covered in this post are a breakdown of the concepts discussed in the yellow paper. I’ve added my own explanations and diagrams to make it easier.

How does Ethereum work, anyway?


I recently joined Edge & Node as a Developer Relations Engineer and have been diving deeper into smart contract development with Ethereum. I have settled upon what I think is the best stack for building full stack dApps with Solidity:

▶︎ Client Framework - React
▶︎ Ethereum development environment - Hardhat
▶︎ Ethereum Web Client Library - Ethers.js
▶︎ API layer - The Graph Protocol

Building Full Stack dApps with React, Ethers.js, Solidity, and Hardhat

The Complete Guide to Full Stack Ethereum Development


Educational sandbox for building on web3. Visually understand how Ethereum works by doing.

ETH.Build


https://www.youtube.com/watch?v=gyMwXuJrbJQ

This course will give you a full introduction into all of the core concepts in blockchain, smart contracts, solidity, NFTs/ERC721s, ERC20s, Coding Decentralized Finance (DeFi), javascript and solidity, Chainlink, Ethereum, upgradable smart contracts, and full stack blockchain development.   

Some of the technologies covered are:
- The Graph
- Chainlink
- Metamask
- Alchemy
- Remix
- Hardhat
- Solidity
- Openzeppelin
- Trail of Bits
- Ganache
- Ethers
- Etherscan
- Coinmarketcap
- Aave
- IPFS
- Fleek.hq
- Filecoin
- NextJS
- Moralis
- Web3uikit
- Opensea
- Pinata
- Nft.storage

 And more!

Follow along with the videos and you'll be a blockchain wizard in no time!  💻 The repository with helpful links to all code, resources, and support forums is located here: https://github.com/smartcontractkit/full-blockchain-solidity-course-js.

This course will give you a full introduction into all of the core concepts related to blockchain, smart contracts, Solidity, ERC20s, full-stack Web3 dapps, decentralized finance (DeFi), JavaScript, TypeScript, Chainlink, Ethereum, upgradable smart contracts, DAOs, the graph, moralis, aave, IPFS, and more. Follow along with the videos and you'll be a blockchain wizard in no time!

Learn Blockchain, Solidity, and Full Stack Web3 Development with JavaScript – 32-Hour Course


Learning Solidity with a collection of YouTube videos and example code.

Learning Solidity


Here we collect and discuss the best DeFi & Blockchain researches and tools 

DeFi Developer roadmap


ETH Gas Tracker helps you discover how gas works, why it matters and help you set optimal gas fees to use the Ethereum network more efficiently. Get real-time gas prices, historical data, and average fees to time your transactions and save money. Ethereum Gas Tracker is the best way to track gas prices and provides an API for developers to integrate gas data into their applications.

Monitor and track the Ethereum, and L2 gas prices to reduce transaction fees and save money

ETH Gas Tracker


This document provides a baseline knowledge of security considerations for intermediate Solidity programmers. It is maintained by ConsenSys Diligence, with contributions from our friends in the broader Ethereum community.

A guide to Ethereum smart contract security best practices

Smart Contract Best Practices

## Problem

The SDK has unit tests with mocked dependencies but no end-to-end system tests that exercise the full flow against real contracts. Encoding bugs, approval flows, recipient handling, and provider routing are never validated on-chain.

## What we need

### Full matrix coverage

Test every combination a developer would encounter:
- **Every wallet provider** (Privy, Turnkey, Dynamic, SmartWallet) × **every chain** (Mainnet, OP Mainnet, Base) × **every namespace function** (getQuote, execute, getMarkets, getMarket, getPosition, openPosition, closePosition)
- **Every swap provider** (Uniswap, Velodrome/Aerodrome) across their supported router types and pool types
- **Every lend provider** (Aave, Morpho) including native ETH paths (WETHGateway) and ERC20 paths
- Both namespace paths: ActionsNamespace (read-only, no wallet) and WalletNamespace (full execution)

### Real execution, no mocks

- Use Anvil forks against Mainnet, OP Mainnet, and Base
- Create real ActionsConfig instances with real providers and real ChainManagers
- Use funded test accounts from Anvil
- Verify on-chain state after execution: token balances, allowances, receipts, recipient addresses

### Test structure and shared state

- Use `beforeAll` / `afterAll` hooks to set up expensive resources (Anvil forks, funded accounts, provider instances) once per suite, not per test
- Tests within a suite should cascade context — e.g., a quote test produces a quote that the execute test consumes, an openPosition test creates state that getPosition and closePosition verify
- Build helper functions and abstractions to minimize per-test boilerplate — e.g., `expectBalanceChange(token, address, fn)`, `withAnvilFork(chain, fn)`, `createFundedActions(chain)`
- Reduce actual test code as much as possible — the matrix should be driven by data (arrays of providers, chains, assets) rather than duplicated test bodies
- Shared utilities in a `setup.ts` or `helpers.ts` that all system test files import

### Edge cases worth covering

- Quote from Actions namespace executed through Wallet namespace (recipient mismatch → re-encoding)
- Existing allowances (verify no redundant approval txs)
- Native ETH swaps
- Quote expiration (advance Anvil time)
- Blocklist enforcement on getMarkets

### Expect to find real bugs

This work will likely surface real bugs in encoding, approval flows, or edge cases. The scope of this issue is **setting up the test matrix and CI job, not fixing the bugs**. When a test reveals a real issue:
1. Write the test anyway
2. Skip or comment out the failing test with a clear note
3. Create a separate issue describing the bug
4. Link the issue in a `// TODO(#xxx)` comment next to the skipped test

Do not block this PR on fixing discovered bugs.

### Infrastructure

- Separate vitest project with extended timeouts
- Separate CI job (see #332, #333) with Anvil and RPC env vars
- Randomized test order

## Existing foundation

`VelodromeSwapProvider.network.test.ts` already has Anvil fork tests for quoting. Expand from there.

## Related

- #332 — Add network fork tests to CI
- #333 — Parallelize tests / split CI into per-package jobs

good first issue

help wanted

actions

TypeScript

Full e2e system tests

## Summary

The lend provider base class has several gaps in allowlist/blocklist enforcement and duplicated logic that should be shared with swap providers.

## Blocklist is non-functional

`marketBlocklist` is defined in `LendProviderConfig` but **never checked anywhere** in `LendProvider`. A developer could configure a blocklist and it silently does nothing.

- `validateConfigSupported()` only checks the allowlist (LendProvider.ts:233-255)
- `filterMarketConfigs()` only filters by chainId/asset, not allowlist or blocklist
- `getMarkets()` doesn't enforce allowlist when custom markets array is provided

## Shared logic to reuse from swap refactor

After the swap provider refactor (PR #311), shared utilities exist that lend providers should adopt:

- **`swap/core/markets.ts`** — `expandMarkets`, `findMarket`, `assetPairs` patterns can inform equivalent lend utilities
- **`utils/approve.ts`** — `buildErc20ApprovalTx`, `buildApprovalTxIfNeeded`, `getApprovalDeficit` — `LendProvider.buildApprovalTx` should delegate to `buildErc20ApprovalTx` (already done)
- **`supportedChainIds()` 3-level intersection** — identical code in both base classes, should be extracted to a shared utility

## What to do

1. Implement blocklist checking in `LendProvider.validateConfigSupported()`
2. Enforce allowlist/blocklist in `getMarkets()` and `getMarket()`
3. Extract shared `supportedChainIds()` filtering to a utility both base classes use
4. Ensure `filterMarketConfigs()` respects both allowlist and blocklist

Lend provider blocklist and abstraction gaps

## Problem

`getQuote()` currently builds both pricing data and swap calldata (via `_getQuote` in each provider). When called from the `ActionsSwapNamespace` (read-only, no wallet), the calldata is wasted — no one can execute it without a wallet.

This is especially costly with price routing (`settings.routing: 'price'`), where `getQuote()` fetches quotes from all eligible providers in parallel. Each quote encodes calldata that will never be used except for the winning quote — and even that won't be used if the caller only needs display data.

## Proposed Solution

Add an internal `includeCalldata` flag to the quoting flow:

1. **`ActionsSwapNamespace.getQuote()`** — calls provider with `includeCalldata: false`. Returns a `SwapQuote` with `execution` omitted or set to a sentinel. Faster because it skips `encodeSwap()` / `encodeCLSwap()` / `encodeUniversalRouterSwap()`.

2. **`WalletSwapNamespace.getQuote()`** — calls provider with `includeCalldata: true` (default). Returns a full `SwapQuote` ready for `execute()`.

3. **Provider `_getQuote()`** — accepts the flag and conditionally skips the encoding step. The quoting step (RPC calls to get amounts) still runs in both cases.

The `SwapQuote` type could make `execution` optional, or we could have two internal return paths with a shared base.

## Why This Matters

- With 2+ providers and price routing, every `getQuote()` call currently does N encoding operations. Only 1 is ever used.
- The `ActionsSwapNamespace` is explicitly read-only — encoding calldata for it is pure waste.
- The encoding involves `encodeFunctionData`, `encodeAbiParameters`, `encodePacked` — non-trivial compute per call.

## Scope

- Add `includeCalldata?: boolean` to `SwapQuoteParams` or as an internal-only param
- Update `_getQuote` in `VelodromeSwapProvider` and `UniswapSwapProvider` to skip encoding when false
- Override `getQuote` in `ActionsSwapNamespace` to pass `includeCalldata: false`
- Ensure `WalletSwapNamespace` defaults to `includeCalldata: true`
- Update tests to cover both paths

Optimize getQuote to skip calldata encoding when wallet is not needed

## Summary

Rename all references to "hosted" wallet provider to "embedded" wallet provider throughout the SDK. The term "embedded" better reflects what these providers do (Privy, Dynamic, Turnkey) and aligns with industry terminology.

## Scope

- ~344 occurrences across ~55 files in `packages/sdk/src/`
- Directory renames: `wallet/*/providers/hosted/` → `wallet/*/providers/embedded/`
- Class renames: `HostedWalletProvider` → `EmbeddedWalletProvider`, etc.
- Type renames: `HostedProviderFactory`, `HostedProviderDeps`, `HostedWalletProviderRegistry`, etc.
- Public API: `actions.wallet.hostedWalletProvider` → `actions.wallet.embeddedWalletProvider`
- Config types: `hostedWalletConfig` → `embeddedWalletConfig`

## Notes

- This is a breaking change for the public API surface
- Should be done as a standalone PR (not mixed with behavioral changes)
- Consider adding a deprecation alias for one release cycle

Rename hosted wallet provider to embedded wallet provider

## Motivation

Each provider (Aave, Morpho, Uniswap, Velodrome) stores contract addresses in different structures. Some use flat `Record<number, Address>`, others use `Record<number, { router: Address, factory: Address, ... }>`, and some mix addresses with metadata (e.g. router type alongside addresses).

This makes it easy to miss address validation when adding a new provider. The existing test file (`validateAddresses.test.ts`) requires explicitly importing each provider's address map — a step that's easy to forget in PR review.

## Standard Structure: `{ contracts, metadata }`

Every provider's per-chain config should follow this pattern, already implemented by Velodrome as the reference:

```ts
interface ProviderChainConfig {
  contracts: Record<string, Address>   // contract name → address (validated)
  metadata: { ... }                    // provider-specific config (not validated)
}
```

### Velodrome (reference — already implemented)

```ts
interface VelodromeChainConfig {
  contracts: {
    router: Address
    poolFactory: Address
    clPoolFactory?: Address
    clQuoterV2?: Address
  }
  metadata: {
    routerType: 'v2' | 'leaf' | 'universal'
  }
}
```

### Uniswap (proposed restructure)

```ts
interface UniswapChainConfig {
  contracts: {
    poolManager: Address
    universalRouter: Address
    quoter: Address
    permit2: Address
    positionManager: Address
  }
  metadata: {}  // no metadata currently needed
}
```

### Aave (proposed — merge two flat maps)

```ts
interface AaveChainConfig {
  contracts: {
    pool: Address
    wethGateway: Address
  }
  metadata: {}
}
```

### Morpho (proposed restructure)

```ts
interface MorphoChainConfig {
  contracts: {
    morphoBlue: Address
    irm: Address
    bundlerV2: Address
  }
  metadata: {}
}
```

## Abstract `contractAddresses()` Method

Add an abstract method to both `SwapProvider` and `LendProvider` base classes, functioning like the existing `supportedChainIds()` — a required method that surfaces provider metadata in a standard way. The compiler enforces implementation, so a PR reviewer immediately sees whether a new provider is returning a complete list.

```ts
abstract contractAddresses(): Record<number, Address[]>
```

Each provider extracts addresses from its `contracts` sub-object:

```ts
contractAddresses(): Record<number, Address[]> {
  return Object.fromEntries(
    Object.entries(MY_CHAINS).map(([chainId, config]) => [
      Number(chainId),
      Object.values(config!.contracts),
    ]),
  )
}
```

## Generic Test (replaces per-map assertions)

```ts
for (const provider of allProviders) {
  for (const [chainId, addrs] of Object.entries(provider.contractAddresses())) {
    for (const addr of addrs) {
      expect(() => getAddress(addr), `chain ${chainId}`).not.toThrow()
    }
  }
}
```

No explicit imports of address maps needed. New providers get validated automatically.

## Work

1. Restructure Uniswap, Aave, Morpho address maps to match `{ contracts, metadata }` (Velodrome already done)
2. Add `abstract contractAddresses(): Record<number, Address[]>` to `SwapProvider` and `LendProvider`
3. Implement in all four providers
4. Replace explicit per-map assertions in `validateAddresses.test.ts` with a generic provider loop
5. Remove hardcoded address map imports from the test file

## Side effects

- Standardizes contract storage across all providers
- New providers get address validation automatically (compiler enforces the abstract method, test iterates generically)
- Easier to catch missing address validation in PR review — the abstract method is a clear signal, same as `supportedChainIds()`
- Contract names as keys makes address maps self-documenting

Standardize provider contract address storage

It is a know issue in Compound Governance that proposal queueing will fail if it contains 2 (or more) actions that have the same target, value, and calldata. While this can be circumvented by adding extra (useless) bytes at the end of the calldata to create unicity, it is possible to create such a proposal and not realised if will never be executable after the voting ends.

We should modify the behavior of `_propose` in `GovernorTimelockCompound` to reject proposals that have duplicated actions

OpenZeppelin Contracts is a library for secure smart contract development.

openzeppelin-contracts

Solidity

Prevent proposals with duplicate actions from being submitted in `GovernorTimelockCompound`

Today, `generate_witness_for_blocks()` executes the block with a `DatabaseLogger` wrapper that intercepts every `get_account_state()`, `get_storage_value()`, and `get_account_code()` call. BAL recording also happens inside `execute_block()` as a side effect. So within a single execution, both the witness data and the BAL are captured.

If the block has already been executed during normal sync (which already produced a BAL for Amsterdam+ blocks), and then someone requests `debug_executionWitness` via RPC — the block gets re-executed just to discover which keys were touched. The BAL from the first execution already contains that exact information.

The optimization would be: for post-Amsterdam blocks where the BAL is available, skip re-execution entirely. Just read the BAL, look up each key in the state trie (with `TrieLogger` to capture trie nodes), and assemble the witness.

This is essentially what `warm_block_from_bal()` already does for prefetching — the same pattern could produce a witness without re-running the EVM.

performance

levm

Minimalist, stable, modular, fast, and ZK native implementation of the Ethereum protocol in Rust. L1 and L2 execution client.

ethrex

Rust

Amsterdam optimizations: reuse BAL for witness generation

In the sync process, we don't have the full picture to propose or attest blocks. We should determine if we are still syncing in some way, and skip block proposal/attestation duties until we catched up.

Tip: check how other lean and beacon chain clients do this

A minimalist and fast Lean Consensus client by LambdaClass, bringing expertise in distributed systems and blockchain infrastructure to deliver a robust and performant implementation.

ethlambda

Don't propose/attest blocks during sync

In `bin/ethlambda/src/main.rs` we have:
```rust
    tokio::signal::ctrl_c().await.ok();
```

We have to make sure we stop genservers gracefully.


Stop genservers gracefully

## Problem

The swap module was updated to use consistent amount naming between inputs and outputs:
- Developer passes `amountIn: number` / `amountOut: number`
- Developer receives `amountIn: number` / `amountOut: number` (human-readable) + `amountInRaw: bigint` / `amountOutRaw: bigint`

The lend module still has the old inconsistent pattern where the same field name changes type between input and output:
- Developer passes `amount: number` (human-readable)
- Developer receives `amount: bigint` (raw) — same name, different type
- Human-readable values use a `Formatted` suffix (`balanceFormatted: string`)

## What we did for swap

- Output fields `amountIn`/`amountOut` changed from `bigint` to `number` (matching input type)
- Raw values renamed to `amountInRaw`/`amountOutRaw`
- Removed `amountInFormatted`/`amountOutFormatted` string fields (replaced by `number` on `amountIn`/`amountOut`)
- Updated all demo frontend/backend consumers

## Changes needed for lend

### SDK types (`packages/sdk/src/types/lend/base.ts`)

| Interface | Current | Proposed |
|-----------|---------|----------|
| `LendTransaction` | `amount: bigint` | `amount: number` + `amountRaw: bigint` |
| `LendMarketPosition` | `balance: bigint` | `balance: number` + `balanceRaw: bigint` |
| `LendMarketPosition` | `balanceFormatted: string` | Remove (replaced by `balance: number`) |
| `LendMarketPosition` | `shares: bigint` | `shares: number` + `sharesRaw: bigint` |
| `LendMarketPosition` | `sharesFormatted: string` | Remove (replaced by `shares: number`) |
| `LendClosePositionParams` | `amount: bigint` | `amountRaw: bigint` (consistency with `LendOpenPositionInternalParams`) |

### SDK providers
- `LendProvider.ts` closePosition: rename internal `amount: bigint` → `amountRaw: bigint` to match openPosition
- Morpho/Aave providers: update `_closePosition` param references
- Position formatting: add `parseFloat(formatUnits(...))` for `balance`/`shares` number fields

### Demo backend
- `packages/demo/backend/src/types/lend.ts` — update response types
- `packages/demo/backend/src/services/lend.ts` — update serialization

### Demo frontend
- `packages/demo/frontend/src/types/api.ts` — `PositionResponse` type
- `packages/demo/frontend/src/hooks/useLendProvider.ts` — `balanceFormatted` → `balance`
- `packages/demo/frontend/src/hooks/useWalletBalance.ts` — same
- `packages/demo/frontend/src/mutations/useLendPosition.ts` — amount references

### Tests
- `packages/sdk/src/lend/core/__tests__/LendProvider.test.ts`
- `packages/sdk/src/lend/namespaces/__tests__/WalletLendNamespace.spec.ts`
- Morpho/Aave provider tests
- `packages/demo/backend/src/services/lend.spec.ts`

## Principle

Developers pass human-readable numbers in, receive human-readable numbers out with the same field names. Raw bigint values are always suffixed with `Raw`.

Align lend amount types with swap pattern

Right now, it is the front-end and back-end's duty to fetch the URL relevant to the transaction hash. Instead, the SDK should include URLs as part of the return object.

Actions SDK should return block explorer URLs

## Summary

The goal of this feature is to add a `format` (alias `fmt`) command which formats a set of source files according to the "defacto" style guide.  For example, something like this:

```
function f(u8 x) -> (u8 r) {
u1 c
  c,r =      x }
```

Would be automatically reformatted like so:

```
function f(u8 x) -> (u8 r) {
  u1 c
  c,r = x 
}
```

Initially, the formatting rules should be straightforward --- in particular, the formatting should not attempt to enforce line breaks (this will be done in a subsequent issue).

## Approach

Implementing the basic formatter should be relatively straight-forward.  The command reads in the source files (as other command already do), then simply [pretty prints ](https://en.wikipedia.org/wiki/Pretty-printing) their contents back out (either overwriting the original contents or placing the output into some output directory specified as cli argument).  The pretty printer should just do the obvious thing, and not attempt to be too complicated at this stage.

## See Also

* (**GoFmt**) formatting tool for `go`: https://pkg.go.dev/cmd/gofmt
* (**GoFumpt**) https://github.com/mvdan/gofumpt
* "The art of formatting code" https://mcyoung.xyz/2025/03/11/formatters/

go-corset

feat: support ZkC `format` command

### Description

This issue proposes integrating AutoTLS into dotnet-libp2p to automate TLS certificate management and improve security for encrypted connections. AutoTLS will provide automatic certificate provisioning, renewal, and validation, reducing manual configuration efforts while ensuring robust encryption.

### Motivation

Currently, dotnet-libp2p does not include automated TLS management, requiring users to manually configure certificates for secure communication. This leads to challenges such as:

- Operational Complexity: Manual certificate issuance and renewal.

- Security Risks: Potential certificate misconfiguration or expiration.

- Developer Experience: Lack of built-in automation makes it harder to deploy secure libp2p nodes.


Other libp2p implementations already support automated TLS:

- [go-libp2p](https://github.com/libp2p/go-libp2p): Uses libp2p-tls for secure connections and integrates with automated certificate management.

- [js-libp2p](https://github.com/libp2p/js-libp2p): Supports TLS 1.3 transport with modular security providers.

- [py-libp2p](https://github.com/libp2p/py-libp2p/pull/1072) - AutoTLS implementation in Py-libp2p

- [py-libp2p example]( https://github.com/libp2p/py-libp2p/pull/1191) -  AutoTLS example implementation in Py-libp2p


By integrating AutoTLS into dotnet-libp2p, we align with these implementations and ensure parity across different libp2p languages.


### Current Implementation

#### Proposed Enhancements

- Automatic Certificate Issuance & Renewal

- Use Let’s Encrypt (ACME protocol) or an alternative automated certificate provider.

- Implement an automated renewal mechanism to prevent expired certificates.

- Ensure proper error handling and logging for debugging failed renewals.


#### AutoTLS Integration into py-libp2p

- Modify TLS transport to support automated certificate provisioning.

- Ensure compatibility with existing security modules (TLS1.3, Noise).

- Provide a toggle flag (enable_autotls=True/False) for optional activation.


#### Configuration & Deployment

- Support a default AutoTLS provider, with configuration options for custom ACME servers.

- Implement lightweight caching to minimize performance overhead.

- Add documentation and examples for developers.

#### Expected Impact

- Improved Security: Ensures all libp2p connections are TLS-encrypted without manual intervention.

- Developer Convenience: Reduces setup complexity, making secure libp2p nodes easier to deploy.

- Automated Management: Certificates are issued and renewed automatically, minimizing operational overhead.


References & Related Work

- [go-libp2p-tls](https://github.com/libp2p/go-libp2p/tree/master/p2p/security/tls) – Secure transport using TLS.

- [js-libp2p-tls](https://github.com/libp2p/js-libp2p-example-auto-tls) – TLS implementation example in JavaScript libp2p.

- [py-libp2p](https://github.com/libp2p/py-libp2p/pull/1072) - AutoTLS implementation in Py-libp2p

- [py-libp2p example]( https://github.com/libp2p/py-libp2p/pull/1191) -  AutoTLS example implementation in Py-libp2p

- [CertMagic](https://github.com/caddyserver/certmagic) – Automated certificate management for Go.

- ACME protocol – Used by Let’s Encrypt for automated certificate provisioning.

#### Next Steps

- Gather feedback from py-libp2p maintainers and contributors.

- Evaluate potential dependencies like Certbot, CertMagic, or an internal ACME client.

- Develop a prototype and open a PR for review.


### Are you planning to do it yourself in a pull request ?

Maybe

enhancement

dotnet-libp2p

AutoTLS Support for dotnet-libp2p

**As a** Java developer
**I want** to have a version of the full-stack-asset-transfer-guide client application in Java
**So that** I can use the workshop material in my programming language of choice

The existing TypeScript client application is located at [full-stack-asset-transfer-guide/applications/trader-typescript](https://github.com/hyperledger/fabric-samples/tree/main/full-stack-asset-transfer-guide/applications/trader-typescript).

fabric-samples

Java implementation of full-tack-asset-transfer-guide client application

**As a** Go developer
**I want** to have a version of the full-stack-asset-transfer-guide client application in Go
**So that** I can use the workshop material in my programming language of choice

The existing TypeScript client application is located at [full-stack-asset-transfer-guide/applications/trader-typescript](https://github.com/hyperledger/fabric-samples/tree/main/full-stack-asset-transfer-guide/applications/trader-typescript).

Go implementation of full-stack-asset-transfer-guide client application

**As a** Java developer
**I want** to have a version of the full-stack-asset-transfer-guide smart contract in Java
**So that** I can use the workshop material in my programming language of choice

The existing TypeScript smart contract is located at [full-stack-asset-transfer-guide/contracts/asset-transfer-typescript](https://github.com/hyperledger/fabric-samples/tree/main/full-stack-asset-transfer-guide/contracts/asset-transfer-typescript).

Java implementation of full-stack-asset-transfer-guide smart contract

**As a** Go developer
**I want** to have a version of the full-stack-asset-transfer-guide smart contract in Go
**So that** I can use the workshop material in my programming language of choice

The existing TypeScript smart contract is located at [full-stack-asset-transfer-guide/contracts/asset-transfer-typescript](https://github.com/hyperledger/fabric-samples/tree/main/full-stack-asset-transfer-guide/contracts/asset-transfer-typescript).

Go implementation of full-stack-asset-transfer-guide smart contract

`deepstate-afl` and other fuzzer executors should have an option to abort the fuzz run and return a non-zero exit code on the discovery of a failing input.  This is essential for using fuzzers in mutation-testing loops!

Sketch:

if `--abort-on-fail` is present, the executor code that checks for `--timeout` (which works correctly) should have an equivalent that watches for the `the_fuzzer/crashes` (or equivalent for non-AFL fuzzers) becoming non-empty and shuts down as with a timeout, but forcing return value (check return from timeout:  that should be zero, since stop on timeout is a normal stop, not sure what it is right now).  libFuzzer may be most difficult to check (since it drops crash files in current dir, I believe), and can operate with a stop-on-fail by default, possibly, anyway.

usability

fuzzing

HIGH PRIORITY

front-ends

A unit test-like interface for fuzzing and symbolic execution

deepstate

Python

Add --abort_on_fail to fuzzing executors

**As a** blockchain developer
**I want** to use the latest version of the @noble/curves crypto library
**So that** I can receive the latest security updates and features

Note that v2 of @noble/curves is an ESM-only module so the way it is imported will need to change. There are also some breaking API changes.

Go, Node and Java client API for Hyperledger Fabric v2.4+

fabric-gateway

Java

Use @noble/curves v2 in Node API

**As a** maintainer
**I want** to use a Docker SDK for Docker operations in Go scenario tests
**So that** I can avoid coordinating Docker CLI command invocations

See https://github.com/docker/go-sdk (or https://pkg.go.dev/github.com/moby/moby/client)

Contribute to open-source Web3 projects

✨ Ethereum.org

✨ Privacy & Scaling Explorations

✨ Solidity