
Discover how $55 million in cryptocurrency vanished in one of the most bizarre thefts in history

Out of the Ether: The Amazing Story of Ethereum and the $55 Million Heist that Almost Destroyed It All tells the astonishing tale of the disappearance of $55 million worth of the cryptocurrency ether in June 2016. It also chronicles the creation of the Ethereum blockchain from the mind of inventor Vitalik Buterin to the ragtag group of people he assembled around him to build the second-largest crypto universe after Bitcoin.

Celebrated journalist and author Matthew Leising tells the full story of one of the most incredible chapters in cryptocurrency history. He covers the aftermath of the heist as well, explaining the extreme lengths the victims of the theft and the creators of Ethereum went to in order to try and limit the damage. The book covers:

The creation of Ethereum
An explanation of the nature of blockchain and cryptocurrency
The activities of a colorful cast of hackers, coders, investors, and thieves
Perfect for anyone with even a passing interest in the world of modern fintech or daring electronic heists, Out of the Ether is a story of genius and greed that’s so incredible you may just choose not to believe it.

The Amazing Story of Ethereum and the $55 Million Heist that Almost Destroyed It All

Out of the Ether


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


Written with the verve of such works as The Big Short, The History of the Future, and The Spider Network, here is the fascinating, true story of the rise of Ethereum, the second-biggest digital asset in the world, the growth of cryptocurrency, and the future of the internet as we know it.

Everyone has heard of Bitcoin, but few know about the second largest cryptocurrency, Ethereum, which has been heralded as the "next internet."

The story of Ethereum begins with Vitalik Buterin, a supremely gifted nineteen-year-old autodidact who saw the promise of blockchain when the technology was in its earliest stages. He convinced a crack  group of coders to join him in his quest to make a super-charged, global computer.

The Infinite Machine introduces Vitalik’s ingenious idea and unfolds Ethereum’s chaotic beginnings. It then explores the brilliant innovation and reckless greed the platform—an infinitely adaptable foundation for experimentation and new applications—has unleashed and the consequences that resulted as the frenzy surrounding it grew: increased regulatory scrutiny, incipient Wall Street interest, and the founding team’s effort to get the Ethereum platform to scale so it can eventually be  accessible to the masses.

Financial journalist and cryptocurrency expert Camila Russo details the wild and often hapless adventures of a team of hippy-anarchists, reluctantly led by an ambivalent visionary, and lays out how this new foundation for the internet will spur both transformation and fraud—turning some into millionaires and others into felons—and revolutionize our ideas about money.

How an Army of Crypto-hackers Is Building the Next Internet with Ethereum

The Infinite Machine


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


Whether you're a curious hacker or an experienced engineer, 30 Days of Web3 is project-based curriculum created by developers to teach you how to build full-stack dapps.


The Ultimate Guide to Building Fullstack Dapps

30 Days of Web3


Wanna dive into Solana development? Let's do it right now with ICB platform🎉
Learn the Rust + Solana development course and get a job as a Solana developer.

The FREE course is available on the platform.
You will learn:

- How to write software using Rust, you will quickly get a good understanding of the type system, ownership, error handling, traits, and more
- How Rust helps you build robust and maintainable software
- What the Rust ecosystem offers
- Who is using Rust
- How can you gain further Rust development knowledge
- What is Solana blockchain, its differences from Ethereum, and cases when you should prefer Solana
- Fundamental features of the Solana such as Account, PDA, CPI, storage and rent, and more
- How to write production-ready programs with the Solana-SDK
- Most common vulnerabilities and security best-practice
- What is the Anchor framework, and what benefits it brings for Rust\Solana developers


 Learn the FREE Rust + Solana development course and get a job as a Solana developer.

Rust-and-Solana-development-for-beginners-ICB


Learn How to Build a Crypto Company

The course videos from a16z’s Crypto Startup School, held in the spring of 2020, are now available to all.

Use the hours of free videos and the reading materials, to navigate the idea maze and start building crypto projects.

Hours of videos, lectures, presentations, real-world insights and fireside chats from some of the best minds in the crypto space.

a16z Crypto Startup School


This course is for students wishing to explore blockchain technology’s potential use—by entrepreneurs & incumbents—to change the world of money and finance.

Kicking off with a review of the technology’s initial application, the cryptocurrency Bitcoin, students will gain an understanding of the commercial, technical and public policy fundamentals of blockchain technology, distributed ledgers and smart contracts in both open sourced and private applications.

The class will then turn to current and potential blockchain applications in the financial sector. This will include reviews of potential use cases for payment systems, central banking, venture  capital, secondary market trading, trade finance, commercial banking, post trade possessing and digital ID.

Along the way, we will explore the markets and regulatory landscape for cryptocurrencies, initial coin offerings, other tokens and crypto derivatives.

This course is for students wishing to explore blockchain technology's potential use—by entrepreneurs and incumbents—to change the world of money and finance.

Blockchain and Money


Distributed systems is the study of how to build a computer system where the state of the program is divided over more than one machine (or "node").

Introductory course in Distributed Systems.

http://www.distributedsystemscourse.com/


Some of the best educational content to help you onboard Web 3 technologies.



The Web 3 education platform for developers, by developers.

Figment Learn


OurNetwork contributors and the Dune team are partnering up to bring to fruition Web3's first learn-to-earn data program. We'll spend 30 days teaching a cohort of 30 students how to analyze data in Web3 and communicate their work publicly.

This first cohort was from Oct - Nov 2021, but all material were released publicly on Mirror for anyone to follow along with. 

**Week one:** Learning to become an Etherscan detective, no using premade tables yet!

- Lecture 1: Looking at basic call and event data on Ethereum L1.
  - navigation on Dune, and how to do basic SELECT queries on data tables.
- Lecture 2: Creating basic statistics for L2 data and bridges potentially.
  - how to do aggregate, group by, and CTE queries

**Week two:** Making sense of smart contracts, specifically learning to work with composability!

- Lecture 3: Decoding smart contracts into data tables and working with data from multiple events
  - How to do basic joins and unions, and using Dune Decode
  - Using tables prices.usd to get to more informed data tracking.
- Lecture 4: Querying across DeFi and DAOs
  - More advanced joins, and windows/partitions.
  - Introduce dex.trades.

**Week three:** Putting it all together, to become an open-source query Dune Wizard!

- Lecture 5: Creating complex but reusable queries.
  - How to create User Generated Views and Materialized views
- Lecture 6: Working with NFTs
  - Working with nft.trades and NFTs more generally

**Week four:** Dashboards and Storytelling, really connect with the community behind the data!

- Lecture 7: Telling stories with your charts, formatting well
- Lecture 8: All about using parameters for really custom and flexible dashboards.


OurNetwork contributors and the Dune team are partnering up to bring to fruition Web3's first learn-to-earn data program

Learn to Earn - Data program


Complete A to Z roadmaps for new and experienced developers to enter web3


LearnWeb3 DAO


What does it mean to own a piece of the internet? Can you sell a meme to the highest bidder? Is the metaverse finally happening? Let's find out together!

Welcome to NFT School, a collective of web developers and technology enthusiasts here to figure out what's going on with non-fungible tokens, or NFTs. In the past few years, NFTs have gone from a niche concern within the blockchain world to a cultural phenomenon that has captured the imagination of artists, technologists, and the mass media.

As builders, we'll be exploring NFTs from the technical side, taking them apart, and seeing how they work. We'll also take a look at some of the use cases for NFTs, so that we can help build new experiences around them.

We'll be building on a background of modern web development, with a focus on JavaScript. Along the way, we'll get familiar with the core technologies that make NFTs possible, like smart contracts and content-addressed storage. If you're a newcomer to the space and find yourself confused, we want to know about it! Please open an issue (opens new window)with any suggestions for how to make this content more accessible.

Community education platform for developers in the non-fungible token space.

NFT School


Token engineering is the design, verification and optimization of token-based economic systems.
It is a cross-disciplinary field that draws from established practices in systems, electrical, robotics & controls engineering, and more. It also draws from fields as diverse as behavioural & ecological economics, operations research, AI & optimization, and others.

It is a methodology that goes all the way from ideation to design, modelling, simulation, testing, deployment, fraud detection & defense, and continuous optimization.

Study, contribute to open-source knowledge & tools, and apply your skills to solve the most exciting challenges in Web3.

Token Engineering Academy


Unit Masters is paving the way for creating a more inclusive and fair economy through equal opportunities and open communities. Connect with crypto enthusiasts from across the globe. 

Unit Masters

Test your Web3 knowledge and claim your ZK certifications.

useWeb3 Academy


Blockchain has emerged from the once shadowy world of cryptocurrency to become [the most in-demand skill in 2020](https://business.linkedin.com/talent-solutions/blog/trends-and-research/2020/most-in-demand-hard-and-soft-skills), according to LinkedIn. The promise of blockchain is huge. And large companies are continuing to hire and expand their blockchain teams, incl. Facebook, Amazon, Microsft, EY, Deloitte, IBM, and Oracle, to name a few. So, it should be well worth the effort to become familiar with how blockchain works, what its perceived benefits are, and as a developer starting building on top of them. 

Over the past few years, I’ve been helping and on-boarding new team members and developers into the blockchain space. This helped me to collect blogs, links, materials, and resources and see which worked well for everyone’s learning journey. It’s time to share that with a broader audience. This guide provides a starting point for developers who’re keen to learn more about blockchain and development on top of Ethereum. It will be opinionated and not contain a full list of everything available. But rather, a concise list of highly recommended options, from my own experiences. 

1. Blockchain foundations
1. Ethereum 101
1. Ethereum Development, Smart contracts & DApps 

# 1. Blockchain foundations 

New to blockchain? Let's start with a bit of the history and its foundations that motivated the creation and development of blockchain.

- [A Cyberphunk's Manifesto](https://www.activism.net/cypherpunk/manifesto.html), Eric Hughes
- [Why decentralization matters](https://onezero.medium.com/why-decentralization-matters-5e3f79f7638e), Chris Dixon
- [The Promise of the Blockchain](https://vimeo.com/161183966) (VIDEO), Vinay Gupta
- [The shift from open platforms to digital commons](http://www.bollier.org/blog/shift-open-platforms-digital-commons), David Bollier
- [Deconfusing decentralization](https://youtu.be/7S1IqaSLrq8) (VIDEO), Greg Slepak


# 2. Ethereum 101 

Now that we have an understanding where we're coming from, let's dive in a little bit deeper into the fundamental components & building blocks.

- [Bitcoin Whitepaper](https://bitcoin.org/bitcoin.pdf), Satoshi Nakamoto - the original whitepaper that started the current trend in blockchain technology: Bitcoin: A Peer-to-Peer Electronic Cash System
- [Ethereum Whitepaper](https://ethereum.org/en/whitepaper/), Vitalik Buterin - a next-generation smart contract & decentralized application platform
- [Ethereum Yellowpaper](https://ethereum.github.io/yellowpaper/paper.pdf), Gavin Wood - a more technical version of the Ethereum whitepaper
- [Smart Contracts](https://www.fon.hum.uva.nl/rob/Courses/InformationInSpeech/CDROM/Literature/LOTwinterschool2006/szabo.best.vwh.net/smart.contracts.html), Nick Szabo
- [Ethereum in 25 mins](https://youtu.be/mCzyDLanA7s) (VIDEO), Vitalik Buterin
- [How does Ethereum work, anyway](https://www.preethikasireddy.com/post/how-does-ethereum-work-anyway), Preethi Kasireddy
- [Mastering Ethereum](https://amzn.to/2VZvfz8) (BOOK), Andreas M. Antonopoulos, Gavin Wood. Or view on [Github](https://github.com/ethereumbook/ethereumbook)
- [How Proof of Stake Ethereum Works](https://stonecoldpat.substack.com/p/how-proof-of-stake-ethereum-works), Patrick McCorry


# 3. Ethereum Development 


Once you've gone through all (or at least most) of the above, you should have a solid grasp of all the concepts. So now we can finally move on to the fun part: actually building stuff! 

To get a full, comprehensive overview of the Ethereum development landscape, check out:
- [Ethereum Developers](https://ethereum.org/en/developers/)
- [The full ConsenSys developer tool list](https://github.com/ConsenSys/ethereum-developer-tools-list)

The Ethereum portal covers sections per programming language, to help you filter out what's relevant for you. Though JavaScript is most commonly used, I'd start with something that you're already familiar with, to flatten the learning curve. Use the above only for future reference. As mentioned previously, I'm trying to keep it simple and offer a few recommended options, from my own experiences. Feel free to discover, try, and learn everything from the developer portals, once you've covered these.

## Other resources

Explore this site to learn more from 

- [🎓 Courses](https://www.useweb3.xyz/courses)
- [📚 Books](https://www.useweb3.xyz/books)
- [💻 Tutorials](https://www.useweb3.xyz/tutorials)
- [🏗️ Starter kits](https://www.useweb3.xyz/starter-kits)
- And more..


This guide provides a starting point for developers who’re keen to learn more about Web3

Beginners Guide to Web3


Blockchain and smart contract development are still relatively new and highly experimental. They require a different engineering mindset than traditional web, or app development where ‘move fast and break things’ has become the norm. 

Blockchain development is much more like hardware, or financial service development. Smart contracts are complex instruments that offer the possibility to have self-enforcing contracts including transparent, tamper-proof, and immutable information. They have the authority to allocate high-value resources between complex systems. Often working autonomously. With huge financial loss at risk. This makes smart contracts critical components in these systems. Development of such components requires more investment, design, and effort upfront. Solid engineering practices, rigorous testing, and a strong security mindset. 

In a series of blog posts, I’m planning to go through several patterns, practices, and principles that can be applied to blockchain and smart contract development to reduce the risks associated with it. 


# Clean Code 

![WTFs/minute](../assets/images/wtfs-minute.jpeg)

In this first article, I’ll cover more general engineering practices based on the concepts of Clean Code. Clean code is a well-known concept within the software development industry. [Robert C Martin, also known as 'Uncle Bob' wrote the famous handbook](https://amzn.to/30RsoKk). Its principles go back to even the earlier concepts of the Agile manifesto and software craftsmanship. It’s a knowledge base for the way we think, write, and read code. Build on decades of wisdom in software development. 

> *“Truth can only be found in one place: the code“* - Robert C. Martin 

Clean code is code that is easy to read. Easy to understand. And easy to maintain. Clean code is an attempt to make sense of the complexity of systems that we’re dealing with. It’s a defense mechanism that can provide guidance when you’re not sure how a change would affect the codebase. While there’s valid criticism on the handbook and the examples are considered outdated, the principles are still very relevant. Especially for object-oriented languages, such as Solidity. They apply to designing and writing secure, open, and immutable code, such as smart contracts.  

# Practices

## Naming
The naming of contracts, functions, or variables should reveal the intention, why it exists, and how it is used. If a name requires comments to explain, then it doesn’t reveal its intent. 

Be consistent in your naming throughout your code. Especially when you’re working with a large codebase. Use the same names for abstract concepts, throughout multiple contracts. 

Use pronounceable names. 

Use searchable names.

> *"There are only two hard things in Computer Science: cache invalidation and naming things."* - Phil Karlton

**References**
- [Code example](https://github.com/wslyvh/clean-contracts/tree/master/1-naming)
- [Solidity Style guide](https://solidity.readthedocs.io/en/latest/style-guide.html)


## Structure & Ordering 

Ordering helps readers identify which functions they can call and to find the constructor and fallback definitions easier.

### Order of Layout 

Layout contract elements in the following order:

1. Pragma statements
1. Import statements
1. Interfaces
1. Libraries
1. Contracts

Inside each contract, library or interface, use the following order:

1. Type declarations
1. State variables
1. Events
1. Functions

### Ordering of Functions 

Functions should be grouped according to their visibility and ordered:

1. constructor
1. receive function (if exists)
1. fallback function (if exists)
1. external
1. public
1. internal
1. private

Explicitly label the visibility of functions and state variables. Functions can be specified as being `external`, `public`, `internal`, or `private`. Please understand the differences between them.

### Ordering of Modifiers

The modifier order for a function should be:

1. Visibility
1. Mutability
1. Virtual
1. Override
1. Custom modifiers

**References**
- [Code example](https://github.com/wslyvh/clean-contracts/tree/master/2-structure)
- [Solidity Style guide](https://solidity.readthedocs.io/en/latest/style-guide.html)


## Documentation & Natspec 

Solidity contracts can have a form of comments that provide rich documentation to others reading the code as well as end-users. This is called the Ethereum Natural Language Specification Format, or [NatSpec](https://solidity.readthedocs.io/en/latest/natspec-format.html).

This documentation is segmented into developer-focused messages and end-user-facing messages. These messages may be shown to the end-user (the human) at the time that they will interact with the contract (i.e. sign a transaction).

It is recommended that Solidity contracts are fully annotated using NatSpec for all public interfaces (everything in the ABI).

**References**
- [Code example](https://github.com/wslyvh/clean-contracts/tree/master/3-documentation)
- [NatSpec](https://solidity.readthedocs.io/en/latest/natspec-format.html)


## Formatting 

Reading code should be like reading this blog, an article, or a book. It should be well formatted. The Solidity style guide provides guidance for writing Solidity code. The goal for it is not to be the right or only way, but to be consistent. 

Consistency can be enforced by using a linter. This not only provides formatting and style guide validation but also includes security validation.

Linters for Solidity
- [Ethlint](https://github.com/duaraghav8/Ethlint) (formerly Solium)
- [Solhint](https://github.com/protofire/solhint) 
- [VS Code Solidity](https://github.com/juanfranblanco/vscode-solidity/)

Use a regular linter for your dapp development (e.g. eslint, depending on your language).

**References**
- [Code example](https://github.com/wslyvh/clean-contracts/tree/master/4-formatting)
- [Solidity Style guide](https://solidity.readthedocs.io/en/latest/style-guide.html)


## Contracts & Data structures 

- Contracts expose behavior and hide data (in abstraction. Not actually hiding data from others. No data on the blockchain is actually hidden, see chapter Contracts). This makes it easy to add new kinds of objects without changing existing behaviors. It also makes it hard to add new behaviors to existing objects.

- Data structures expose data and have no significant behavior. This makes it easy to add new behaviors to existing data structures but makes it hard to add new data structures to existing functions.

Clear separation of the two is important, due to the contract’s immutability. If you want to add logic or deploy new contracts, you want to be able to utilize the existing data structures. Separating the two can be done by storage contracts. We’ll cover these in more detail in another blog post. 


## Systems 

Keep it Simple Stupid ('KISS'). Complexity increases the likelihood of errors and unexpected behavior. Contracts should have one responsibility, and only one reason to change, supporting the Single Responsibility Principle. It's one of the most important concepts in OO design.

Keep your contracts small. Every line of code in a smart contract costs money to execute and storing data is expensive. A best practice is to store a pointer to data in a smart contract, rather than storing the data itself. For example, data can be stored using decentralized data storage providers such as IPFS.

Modularize your contracts to keep them small and utilize existing standards & libraries (see 'Standards & Libraries'). 

The same applies to functions. Functions should do one thing. They should do it well. They should do it only.

On blockchain everything is public. Private data and variables within a smart contract are not actually private. "Private" means within the execution scope of the contract, but the data is public and can be read by anyone. Keep this in mind when designing your programs.

Only use blockchain and smart contracts for the parts that need to be decentralized. 

> *"The first rule of functions is that they should be small. The second rule of functions is that they should be smaller than that."* - Robert C. Martin 


## Standards & Libraries 

An intrinsic feature of smart contracts is its composability. Turning every contract into a component and potential building block that others can leverage. A lot of these building blocks exist already and standards ensure the ease of use and development. The most well-known standard was created for the emerging token ecosystem and the exchanges serving it: the ERC20 standard.

Before you dive in and start writing your own, custom smart contracts, it’s wise to check if any standards or open-source components exist. If such standard contracts exist and are properly tested and audited, they can minimize the risk in your programs.

- Ethereum Improvement Proposals (EIPs) describe standards for the Ethereum platform, including contract standards. [Finalized ERC's](https://eips.ethereum.org/erc#final)
- [OpenZeppelin Contracts](https://openzeppelin.com/contracts/)


## Error handling 

Exceptions are a crucial part of modern software engineering. They require special treatment and can be extremely powerful. Instead of fighting them, we should try to leverage them, as an unhandled exception may cause unexpected behavior. 

When an exception is thrown in Solidity code, all state changes are rolled back and further execution is halted. Luckily, exception handling is built into Solidity (since 0.6). This is only available for external calls. 

Provide enough context with your exception to determine the source and cause of your error. 

Try to write tests that throw these exceptions.

Don’t return null. Don’t pass null to functions.

Guard Checks can help that the behavior of a smart contract and its input parameters are as expected.

Use `assert()`, `require()`, `revert()` properly. **assert** should be used to test for internal errors, and check invariants.
**require** should be used to test that inputs, contract state variables, or return values from external contracts are valid. 

If a transaction doesn’t have enough gas to execute, the out of gas error is not caught.


## Testing 

![Test my code](../assets/images/test-my-code.jpeg)

The same rules for clean code, apply to testing. Clean tests are tests that are easy to read. Easy to understand. And easy to maintain. Tests help you keep your code flexible, maintainable, and reusable. They validate the behaviors, reduce the risks of making unintended changes, and save time debugging and writing your code. 

### F.I.R.S.T

- **Fast** — Test should fast enough so that you want to run them frequently. It should help speed up your development process, not hinder it
- **Independent** — Tests should be independent of each other and able to run in any order
- **Repeatable** — Tests should be repeatable in any environment
- ** Self-validating** — Tests should a clear (boolean) output if it passes. 
- **Timely** — Tests need to be written in a timely fashion. Just before the production code. 

### AAA

The AAA (Arrange-Act-Assert) pattern is one of the most common standards in software testing. It suggests dividing your tests into the corresponding sections: arrange, act, and assert. Each one of them is responsible for the part in which they are named after.

- **Arrange** - The code required to set-up your test
- **Act** - Invocation of the method being tested
- **Assert** - Check whether the expectations are met

Use only one assert per test.

### Separation of tests 

- **Unit tests** determine whether an individual unit of source-code is fit for use. This is typically a single function, tested with different parameters to ensure it returns the expected values.
- **Integration tests** determine if independently developed units of software work correctly when they are connected. For smart contracts, this means interactions between different components of a single contract, or across multiple contracts.

### Test coverage 

Writing good tests to ensure your app is working as intended is not enough. If you're not measuring anything, it's hard to say exactly how much of your code is being tested. Test coverage (or code coverage) is a useful tool for finding untested parts of a codebase. 

There is much debate over how much should be covered. Just your best judgment, but aim for as high as possible. Untested code could do anything and result in unexpected behavior.

### Testing Tools 

- [Buidler](https://buidler.dev/) -  A task runner for Ethereum smart contract developers that allows you to deploy your contracts, run your tests and debug your code
- [OpenZeppelin Test environment](https://docs.openzeppelin.com/test-environment/) - Test Environment is a smart contract testing library: it provides utilities that help you write tests, but it doesn’t run your tests for you. Works with Mocha 
- [Brownie](https://github.com/eth-brownie/brownie) - A Python-based development and testing framework for smart contracts targeting the Ethereum Virtual Machine
- [Truffle](https://www.trufflesuite.com/truffle) - A development environment, testing framework and asset pipeline for blockchains using the Ethereum Virtual Machine (EVM)
- [Ganache](https://www.trufflesuite.com/ganache) - A personal blockchain for Ethereum development you can use to deploy contracts, develop your applications, and run tests
- [Solidity-coverage](https://github.com/sc-forks/solidity-coverage) (formerly Solcover) - Code coverage for Solidity smart-contracts


## Security & code analysis 

Static code analysis is the analysis of software that is performed without actually executing the program. In most cases the analysis is performed on some version of the source code. Anlaysis is usually performed by an automated tool (e.g. Sonarqube).

Analysis tools for smart contracts help identify smart contract vulnerabilities. These tools run a suite of vulnerability detectors and print out a summary of any issues found. 

### Analysis Tools

- [Echidna](https://github.com/crytic/echidna) - Ethereum smart contract fuzzer
- [Manticore](https://github.com/trailofbits/manticore) - Symbolic execution tool
- [Mythril](https://github.com/ConsenSys/mythril) - Security analysis tool for EVM bytecode
- [Oyente](https://github.com/melonproject/oyente) - An Analysis Tool for Smart Contracts
- [Slither](https://github.com/crytic/slither) - Static Analyzer for Solidity

### Gas Optimization

Optimizing gas costs can be a worthwhile endeavor, to reduce costs both for your own deployments, as well as for your end-users. Network usage is progressively increasing, with current gas costs at its peak. As the ecosystem continues to grow, so too will the value of gas optimization. We’ll cover these in more detail in another blog post. 

Analyzing your code can be done by using [eth-gas-reporter](https://github.com/cgewecke/eth-gas-reporter). It prints estimates of gas costs per function, or of each deployed contract. 



## Continuous Integration 

While not part of the clean code principles, continuous integration (‘CI’) has become a fundamental practice for any type software development. One of the key benefits of integrating regularly is that you can detect errors quickly and locate them more easily. 

It is based on a set of key principles.

- Keep a single repository where all the code lives and where anyone can obtain the current and previous versions (e.g. Git)
- Automate the build process so that anyone can use it to build directly from the sources (e.g. Truffle teams, Travis CI)
- Automate your tests so that anyone can run a full test suite at any time (see chapter Testing)
- Make sure anyone can view the results and get the latest executable from the build process

> *"Continuous Integration doesn’t get rid of bugs, but it does make them dramatically easier to find and remove."* - Martin Fowler

![Ship all the code](../assets/images/ship-all-the-code.jpeg)


## Further Reading 

Check out my [Clean Contracts](https://github.com/wslyvh/clean-contracts) repo for supporting code example from each chapter.

- [Clean Code](https://amzn.to/30RsoKk), Robert C. Martin
- [Solidity Patterns](https://fravoll.github.io/solidity-patterns/), Fravoll 
- [Ethereum Smart Contract Best Practices](https://consensys.github.io/smart-contract-best-practices), ConsenSys
- [Best Practices for Smart Contract Development](https://yos.io/2019/11/10/smart-contract-development-best-practices/), Yos Riady

Blockchain and smart contract development require solid engineering practices, rigorous testing, and a strong security mindset. This guide covers several patterns, practices, and principles to reduce the risks associated with it.

Clean Contracts - a guide on smart contract patterns & practices


Web3 is about the next evolution of the web. A web that is more open, transparent and permissionless and runs on decentralized infrastructure such as blockchains. Global and decentralized applications (DApps) that anyone can interact with. They often have native assets integrated (such as Ether) to transact value, but are not just about money or payments. These decentralized applications offer a range of digitial services, such as storage, bandwidth and computation without any risk of downtime, censorship, fraud, or 3rd-party interference.

## Benefits

- **Open** - in that they are built from open-source software, by an open and accessible community of developers and executed in full view of the world. 
- **Trustless** - in that the network itself allows participants to interact publicly, or privately without a trusted third party
- **Permissionless** - in that anyone, both users and suppliers, can participate without authorisation from a governing body


## Opportunities

- Financial Tools (payments, fund raising, lending, borrowing,..)
- Identity solutions (self-sovereign, decentralized identifiers,..) 
- More secure voting and governance mechanisms
- Efficient resources management (CO2 tracking, smart grid’s,..)
- Digital ownership registries (e.g. land, collectibles, NFT’s,..)
- Supply chain tracking


## Web3 Development

[useWeb3](https://www.useweb3.xyz/) is a learning platform for developers to explore and learn about Web3. Whether you’re a new dev getting your hands dirty for the first time, or a seasoned developer making the transition into the Web3 space. 

Explore the latest resources, tutorials, challenges, tools, courses and boilerplates and start learning. Once you’re ready, browse the job board to land a job at some of the leading companies that work on core, open-source infrastructure, products, tools, frameworks, DAO's, etc.


## Further reading

- [A Cyberphunk's Manifesto](https://www.activism.net/cypherpunk/manifesto.html), Eric Hughes
- [The Meaning of Decentralization](https://medium.com/@VitalikButerin/the-meaning-of-decentralization-a0c92b76a274), Vitalik Buterin
- [Why decentralization matters](https://onezero.medium.com/why-decentralization-matters-5e3f79f7638e), Chris Dixon
- [What Is Web 3.0 & Why It Matters](https://medium.com/fabric-ventures/what-is-web-3-0-why-it-matters-934eb07f3d2b), Max Mersch and Richard Muirhead
- [What exactly is Web3?](https://youtu.be/l44z35vabvA), Juan Benet (VIDEO)


Web3 is about the next evolution of the web. A web that is more open, transparent and decentralized.

What is Web3


This is a video from Rekt, the dark web of DeFi journalism.


A dystopian view of the new financial world emerging from crypto

Hopium Diaries

Devs Do Something


We are not shy about getting technical during the discussion and feel long form conversation is the best way to share information. We hope you enjoy!

Hashing It Out is a podcast that dives into the weeds of technology and how it impacts society.

Hashing it Out


Sina Habibian previously led engineering at a Layer 2 protocol and worked on ecosystem development at the Ethereum Foundation.

Into the Bytecode is a podcast about the ideas shaping crypto.

Into the Bytecode


Exploring the intersection of society, culture, and crypto.

On The Other Side


An experimental new show - shadowy super coders. Great conversations with the people building the future of Web3.

Shadowy Super Coders


ConsenSys, the market-leading blockchain technology company, presents "SIGNAL," a podcast to empower the technology ecosystem through stories from the people that are participating in the next generation of the internet. Hear from the most captivating Ethereum insiders—from technologists and entrepreneurs to designers and creatives from all around the world—and join us for inspiring conversations on the future of finance, crypto, and what's making the Web3 world.

a podcast to empower the technology ecosystem through stories from the people that are participating in the next generation of the internet.

SIGNAL


Vitalik Buterin, creator of Ethereum, on understanding Ethereum, ETH vs. BTC, ETH2, scaling plans and timelines, NFTs, future considerations, life extension, and more (ft. Naval Ravikant)

Vitalik Buterin provides a short overview of Ethereum and how it compares to Bitcoin and other platforms.

Vitalik Buterin on the Tim Ferris podcast


[boilr3](https://github.com/Envoy-VC/boilr3) is a comprehensive starting point for building decentralized applications using [Next.js](https://nextjs.org/) and [TypeScript](https://www.typescriptlang.org/).

**Tech Stack**

- Next.js
- TypeScript
- TailwindCSS
- RainbowKit
- wagmi


An open-source all-in-one Next.js + Typescript based dApp boilerplate featuring RainbowKit, TailwindCSS and wagmi.

boilr3


The complete toolbox to create full-stack web3 applications!


The complete toolbox to create web3 applications.

Create Web3 Dapp


**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


a16z Crypto Startup School is a series of lectures and discussions given by experts to help technologists learn how to build crypto companies.


DeFi is one of the most interesting and fastest growing movements with an amazing potential of completely disrupting traditional finance. Although I believe DeFi is the future, it can be quite difficult for newcomers as it combines a lot of elements from two poorly understood subjects: finance and technology. I started Finematics to make it easier to understand this new, fascinating world.

Educational videos on DeFi (Decentralized Finance).

Finematics


The Buidl Guidl is a curated group of Ethereum builders creating products, prototypes, and tutorials with scaffold-eth.

Buidl Guidl


If you could learn about anything in this space, what would it be? Whether you're interested in NFTs, crypto, the blockchain, or Web3 as a whole - no topic is off limits for our incredible experts.

Ask any web3 question – get an answer within 24h.

curious.xyz


Nowadays there are countless well-made resources on how to learn blockchain development of all kinds and with different specializations in mind, however, it is still very hard to get guidance and personalized suggestions based on your interests. I am writing this guide in order to provide an aggregator of all the resources that I’ve found over the years, plus give some opinionated commentary on how to approach them and how to use them in order to maximize learning and practical understanding in order to get building cool things in the space as soon as possible.

This guide will focus on the Ethereum ecosystem as that’s where most developers and applications are. If you are interested in other ecosystems that are non-EVM compatible and are not L2s on Ethereum, then check out their respective documentation or guides written by their developer communities. Examples of other non-EVM compatible blockchains that are popular are Solana (Rust/Anchor), Polkadot (Rust/Substrate), Cosmos, Terra, and others. Most of these blockchains do or will support the EVM stack through various initiatives like Neon EVM (Solana), Moonbeam/Moonriver (Polkadot/Kusama), EVMOS (Cosmos), etc.

I really want this guide to become a community-sourced public good that everyone will be able to take advantage of. I will do my best to present it to the wider blockchain developer community to get constructive feedback, proofreading help, and insight into how to make it the best available guide available.

devpill.me


lil web3 aims to build really simple, intentionally-limited versions of web3 protocols & apps. By distilling them to their roots, we can better understand how they work.

- lil ENS
- lil OpenSea
- lil Fractional
- lil JuiceBox
- lil Flash Loan
- lil Gnosis
- lil Superfluid


Simple, intentionally-limited versions of web3 protocols & apps.

lil web3


This is my exhaustive personal opinions, brain dump, examples, guide, curated resources on web2/3 development.

No matter you're complete newbie to even web2 or web2/3 dev with some experience, hope you'll find this doc helpful to get comfortable with web3 development.


A very exhaustive third brain (personal opinions, examples, guide, curated resources) on web2/3 development / security

thirdbrain


Web3 is an idea for a new iteration of the World Wide Web based on blockchain technology, which incorporates concepts including decentralization and token-based economics.

Web3 by Example is a hands-on introduction to web3 development using annotated example programs. 

Web3 by Example is a hands-on introduction to web3 development using annotated example programs.

Web3 by Example


The starter pack is split into 4 crypto concepts (web3, DAOs, NFTs & DeFi).

#web3

📚 The Cryptopians

📚 Token Economy

🏗️ Nexth Starter kit

🌐 devpill.me

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