Bitcoin Cash is one chain of Satoshi Nakamoto's blockchain invention which was deliberately hard-forked on August 1st, 2017. It shares the whitepaper, first block, and all bitcoin block history prior to the fork. It attempts to implement the central idea outlined in that paper.

Whitepaper TL;DR:

A person controls unspent value at some address with a secret key.
Value is transferred permissionlessly by signing a transaction with the secret key.
The network is maintained and controlled by rewarding new value to the network operators.
Tracking a list of unspent value is manageable on a global scale.

Below is a copy of the original nine page whitepaper:

Archived copy of the bitcoin whitepaper from bitcoin.org
bitcoin whitepaper via ipfs
Websites hosting the bitcoin whitepaper, with sha256 hashes calculated hourly.
Instructions and code for building the original paper encoded on the blockchain on 2013-04-06.

Projects Built on Bitcoin Cash

Shipyard

These are up and coming projects in beta:

be.cash [whitepaper] [demo] - point of sale system using stable tokens and nfc
causes.cash [src] - a site for creating your own fundraising campaign
Electron-Cash 4.1.* (CashFusion Alpha) [src] [bin]
stamp [src] - A Bitcoin Cash powered chat electron app on testnet
AnyHedge [whitepaper] [lib] - A Decentralized Hedge Solution for Arbitrary Assets on Bitcoin Cash

Shipped

All of these apps are mostly stable and active. Always check the notes of a particualar project before risking a large sum of value. Links are checked on a weekly basis, but function is not checked.

Open Source Wallets

Below are non-custodial open-source wallets that use features specific to Bitcoin Cash.

Desktop

Electron-Cash [src] - the awesome SPV wallet for Bitcoin Cash
crescent.cash [src] - a Bitcoin Cash wallet in java.

Electron-Cash Plugins

Flipstarter Plugin - plugin for crowdfunding
Mecenas Plugin - recurring payments
Last Will - dead man smart contract creation
More Comprehensive List - hosted by im_uname

Mobile

Electron-Cash - Android [src] and iOS [src] versions available with more limited functionality
crescent.cash [src] - Android wallet with SLP, BIP70 and sms features.
neutrino [src] - Android wallet with advanced privacy features.
Badger Mobile [src] - Mobile App wallet with SLP and CashID support for iOS [src] and Android [src]

Cli

bchwallet - a secure Bitcoin Cash wallet daemon written in Go (golang)
openbazaar wallet - an SPV wallet in Go (golang) developed for openbazaar2

Browser

blockparty [src] [docs] - A simple in-browser web wallet using bitox.earth
mint [src] - Non-custodial web-based tool to manage your SLP tokens.
nito [src] - Web wallet designed for easily on-boarding new users

Paper/Offline Generator

Cash Address Generator - reputable javascript random address generator suitable for offline use.
BCH Gifts - generate reclaimable preloaded paper private keys as gifts.
SLP wallet generator [src]- offline generator for Simple Ledger addresses

Network

doublespend.cash - view Bitcoin Cash double spend attempts.
tx street - transaction visualizer, updated with popular protocols.
privacy stats - recent list and totals of shuffles & fusions.
fork.lol - Site to monitor network health in relation to BTC.

read.cash - a conventionally hosted long-format blogging platform, with BCH tipping for content.
flipstarter Introduction - a crowd funding app using anyone can pay multisig transactions.
memo.cash - short message social media site with decentralized SLP token exchange.
member.cash - longer format social media platform with voting, tipping, moderation and filtering.

Decentralized Marketplace

OpenBazaar - desktop (daemon w/ electron app) p2p marketplace using multisig transactions.
Havenapp - mobile implementation of openbazaar.

Entertainment

blockchain.poker - Texas Hold'em using zero-conf for BCH deposits, BTC and BSV supported.
Satoshi dice - a provably fair dice game.
Spin BCH - Spinning wheel based gambling using zero-conf

Web

Pay Button [src] - a simple snippet to accept Bitcoin Cash on your website.

Utilities

CashAccount - Online utility for cashaccounts (address handles).
Bitcoin.com Tools - A mix of Bitcoin utilities.

Services & Bots

chaintip - An on-chain non-custodial tipping bot for reddit/twitter & github.
tipbitcoin.cash - Live tipping bot for video streamers.
bitcash - A custodial tipping bot for github.
Chaintip Bounties - BCH bot for github bounties.
BCH Pizza - BCH shared bounty site for pizza shop adoption.
Satoshi Wall - a non-custodial payment wall tiered content site.

Launchpad

Awesome projects which appear to be dormant due to lack of use.

lazyfox - a Bitcoin Cash powered question and answer / tasking platform, 🚧 under revision.
stack exchange - an unsuccessful initiative to create a Bitcoin Cash stack exchange.

In the Boneyard

These ships are apparently in long term storage

SLPDEX [src] - Decentralized token exchange, errors on slp/list

Merchants and Services Accepting Bitcoin Cash

A Short List

These vendors have accepted bitcoin for years and are committed (or sympathetic) toward the idea of electronic cash payments.

Although some of these may appear to only accept Bitcoin (BTC), they do, in fact, accept Bitcoin Cash also.

Namecheap - dns, ssl and some packaged hosting.
CheapAir - for your travel needs.
items sold by Newegg - good for a great headset.
Lanieri - makes a good suit.
partsoven - for that 3rd dimension of building.
AdaFruit - hardware dodads via bitpay

Geographic lists

member map - permanent on-chain geographic tags utilizing extensions to the memo protocol.
Bitcoin.com map - website and mobile app for discovering merchants, formerly marco coino.
Greenpages map - merchant finder with advanced filtering.

Projects dedicated to listing or enabling eCommerce.

The Accept Bitcoin Cash Initiative - list of merchants and stores.
Bitpay Directory - partial and outdated list of websites using bitpay as a payment processor.
Openbazaar Listings - web preview for distributed multicoin marketplace.
Purse.io - service to privately purchase goods on Amazon.com (US) at a discount.

Some Charities and Foundations

Just some good charities for the world at large.

Save the Children - Powered by The Giving Block
Electronic Freedom Foundation
Tails

eCommerce Merchant Resources

Bitcoin Cash Open-Source plugins

CryptoWoo for WooCommerce - Bitcoin Cash integration for CryptoWoo

BCH-to-Fiat Payment Processors

BitPay developer Integrations [api docs]
Coinpayments Tools [plugins] - Integrations for coinpayments
GoCoin - GoCoin integrations, libraries & API docs.
Coinbase - Merchant integrations for coinbase

Payment Processor Status

status.coinbase.com - Dashboard with subscriptions endpoints and post-mortems
status.bitPay.com - Current status with recent incidents

Documentation

Roadmaps

Bitcoin Cash Roadmap - "official."
Detailed Specs of Proposed Improvements - an ongoing list.
Coin Dance list - with broader developments and proposals in various states from many groups

General

Full-Stack how-to - Chris Troutner's introduction to developing on Bitcoin Cash
Mastering Bitcoin Cash - Fork of Andreas M. Antonopoulos' book under Creative Commons
developers.cash - many useful resources and tools
bitcoincash.org dev docs - libraries for interacting with Bitcoin Cash
Bitcoin.com Developer Resources - Tooling and documentation developed by bitcoin.com
tutorial.cash - video tutorials
Learn Bitcoin Cash - Early general introduction to Bitcoin Cash.

Base Protocol

Base Protocol Reference - maintained by Bitcoin Unlimited

Secondary protocols

Bitcoin Cash Standards is a site dedicated to collecting, some of which are listed below:

Cashaddr - Format for Bitcoin Cash addresses
Payment Requests Specification (BIP-0070) - For dealing with invoice style payments at specific amounts.
Cash Accounts - attach a human readable name to Bitcoin Cash addresses
Memo Protocol - for the on-chain tweet style social media app
Memo with Member extensions - for creating a reddit/hn style app
Simple Ledger Protocol (SLP) [specs] - for handling ERC-20 style tokens
CashShuffle [spec] - a privacy protocol for combining transactions with others, splitting to the lowest common amount.
CashFusion [spec] - a privacy protocol for privately and trustlessly joining coin amounts.
CashID - Specification using Bitcoin Cash for secure authentication.
Avalanche [snowglobe spec] [🐉implementation (golang)] - local-state reconciliation
Price Oracle [🐉implementation] - Price oracle work in progress

Bitcoin Script

meep - a command line Bitcoin Cash script debugger.
bitauth ide [src] - an integrated development environment for bitcoin authentication.
spedn [src] - a high level smart contract language that compiles to Bitcoin Cash Script.
Cashscript - a solidity-style language that compiles to Bitcoin Cash Script.
Cashscript alt-docs - documentation for Cashscript hosted at bitcoin.com.

Software

Full Nodes

BitcoinABC [mirror] - a full node implementation of the Bitcoin Cash protocol. The dominant mining implementation, C/C++.
BitcoinUnlimited [src] - a full node implentation focused on supporting user needs, C/C++.
bchd [src] - alternative implementation written in Go (golang)
Bitcoin Verde [src][docs] - java implementation with the goal of being interoperable with mining nodes
BCHN [src] - a descendant of the Bitcoin Core and Bitcoin ABC software projects with independant development team. C/C++.
Flowee the Hub [src] - a node supporting a suite of software focused on payment integration. C++
Knuth [src]- a high performance implementation of the Bitcoin protocol focused on applications needing extra capacity and resilience.

Full Node Development Tools

Bitcoin Cash Research - Site dedicated to technical research on Bitcoin Cash.
Difficulty Simulator - Simulator for testing algorithms for difficulty adjustment with rational miners.
Difficulty Simulator - A more up to date difficulty adjustment with rational miners.
Workgroups - Entrypoint for discussion around particular roadmap sub-projects.

Open-Source Teams Builing Upon Bitcoin Cash

If you want to go fast, go alone. If you want to go far, go together.

-- An African Proverb.

There are various groups developing software stacks & apps for the broader ecosystem.

Bitcoin.com [repos] - Prolific group developing webapps, mobile apps, and new tooling for deployed at bitcoin.com. (Typescript with some Javascript et al.)
FullStack Cash [repos] - Team building web/ipfs apps based on BitBox compatible stack. (Javascript)
gcash [repos] - Team building apps, a wallet and tooling using an alternative full node directly. (Golang)
Simple Ledger [repos] - Group leading SLP token integration. (Typescript & Python)
General Protocols [repos] - Team researching and developing protocols for non-custodial and trustless networks using BitBox. (Typescript and Javascript)
Electron Cash [repos] - Team maintaining a desktop SPV wallet with plugins and mobile app (Python)
Flowee [repos] - Team maintaining a non-mining full node and services to access the Bitcoin Cash network. (C++, NodeJs et al)

SPV servers

Fulcrum - A fast & nimble SPV Server for Bitcoin Cash
ElectronX [docs] - A reimplementation of Electrum-Server for a future with bigger blocks. ⚠️ See changlog note v1.15.0 ⚠️
Electron Cash ElectronX [docs] - Electron Cash maintained version of ElectrumX. ⚠️ See note on main branch above ⚠️

Libraries & SDKs

Javascript

bchjs [docs] - JavaScript Libraries based on BITBOX.
libcash-js - javascript library using the flowee api.
bitcore-lib-cash - javaScript library, maintained by bitpay.
bchd grpc web-client - protobuf based javascript client for interacting with bchd full nodes.
electrum-cash [docs] - JavaScript library that lets you connect with one or more Electrum servers.

Typescript

Bitbox SDK [docs] - library for interacting with BCH via rest.bitcoin.com.
Badger SDK - browser extension wallet supporting BCH and SLP on webpages.
libauth [src] - a zero-dependency, typescript bitcoin library, including WASM crypto functions, BTC, but BCH friendly. (formerly bitcoin-ts)

Python

bitcash [src] - python3 library.
bchd python bindings - sample protobuf based python client for bchd.

Java

bitcoincashj - Bitcoin Cash library for Java

PHP

cashp - Library for BCH and SLP tokens

Language Agnostic

grpc-bchrpc-star - Client libraries for bchd rpc generated from protocol buffers
BitBox OpenAPI 3 (Swagger) spec - for rest.bitcoin.com see: openapi-generator

SLP Token Specific Tools

Electron-Cash SLP Edition
slpjs - library for interacting with SLP tokens, dependent on bitbox.
SLPDB - simpleledger indexer
goslp - SLP go libraries
SLP Indexer - bitcoin.com indexer
SLP SDKs - for android and iOS.

README.md

Contents

Whitepaper