Get started with Metamask, an Ethereum wallet that you’ll need to start building your decentralized applications. We teach you how to install, configure, and fund your Metamask wallet with Ropsten LINK and ETH.

Documentation for setting up Metamask: https://docs.chain.link/docs/install-metamask

Chainlink is a decentralized oracle network that enables smart contracts to securely access off-chain data feeds, web APIs, and traditional bank payments. Chainlink is critical to connecting the blockchain ecosystem to the rest of the world.

Metamask download: https://metamask.io/download.html

NOTE: Ropsten is currently down, please use Kovan or another testnet instead:
Kovan LINK faucet: https://kovan.chain.link/
Kovan ETH faucet: https://faucet.kovan.network/
Kovan LINK address: 0xa36085F69e2889c224210F603D836748e7dC0088

Ropsten ETH faucet: https://faucet.ropsten.be/
Ropsten LINK faucet: https://ropsten.chain.link/
Ropsten LINK contract address: 0x20fE562d797A42Dcb3399062AE9546cd06f63280

Learn more about Chainlink
Documentation: https://docs.chain.link/docs/getting-started
Discord: https://discordapp.com/invite/aSK4zew Very active and developer focused!
Website https://chain.link
Building DeFi Applications: https://defi.chain.link/
Twitter https://twitter.com/chainlink
Telegram https://t.me/chainlinkofficial

Get introduced to the solidity programming language, which is used to build smart contracts on the Ethereum blockchain. We will also walk through Remix, the web IDE for solidity. This will be an example walkthrough using Chainlink, where you will learn how to deploy, fund, and interact with a Chainlink node.

Chainlink is a decentralized oracle network that enables smart contracts to securely access off-chain data feeds, web APIs, and traditional bank payments. Chainlink is critical to connecting the blockchain ecosystem to the rest of the world.

NOTE: Ropsten is currently down, please use Kovan instead:
Kovan Remix Code from video: https://remix.ethereum.org/#version=soljson-v0.6.7+commit.b8d736ae.js&optimize=false&evmVersion=null&gist=2324e6830b66ea954b674748b7676c58

Ropsten Remix Code from the video (with notes): https://remix.ethereum.org/#version=soljson-v0.6.2+commit.bacdbe57.js&optimize=false&gist=9507bdea4570e56067a0ab0ecb351b67&evmVersion=null
Remix Link without Code: https://remix.ethereum.org/
Chainlink Example Walkthrough Docs: https://docs.chain.link/docs/example-walkthrough

Other resources for learning to develop in solidity:
Dapp University: https://www.youtube.com/watch?v=3681ZYbDSSk
Cryptozombies: https://cryptozombies.io/en/course/
Solidity Docs: https://solidity.readthedocs.io/en/v0.6.11/
Udemy Course: https://www.udemy.com/course/ethereum-and-solidity-the-complete-developers-guide/

Learn more about Chainlink :
Documentation: https://docs.chain.link/docs/getting-started
Discord: https://discordapp.com/invite/aSK4zew Very active and developer focused!
Website https://chain.link
Building DeFi Applications: https://defi.chain.link/
Twitter https://twitter.com/chainlink
Telegram https://t.me/chainlinkofficial

Understand what Blockchain Oracles are, and the challenges that they face in the Oracle Problem. Understand why your smart contracts and blockchain platforms can’t themselves make API calls as part of their consensus. Then, understand how Chainlink solves each one of these.

Chainlink is a decentralized oracle network that enables smart contracts to securely access off-chain data feeds, web APIs, and traditional bank payments. Chainlink is critical to connecting the blockchain ecosystem to the rest of the world.

Oracles & the Oracle Problem:
More on Oracles: https://blog.chain.link/oracles-the-key-to-unlocking-smart-contracts/
The Oracle Problem: https://blog.chain.link/what-is-the-blockchain-oracle-problem/
Why can’t blockchain smart contracts make API calls: https://ethereum.stackexchange.com/questions/301/why-cant-contracts-make-api-calls

Learn more about Chainlink :
Documentation: https://docs.chain.link/docs/getting-started
Discord: https://discordapp.com/invite/aSK4zew - Very active and developer focused!
Website https://chain.link
Building DeFi Applications: https://defi.chain.link/
Twitter https://twitter.com/chainlink
Telegram https://t.me/chainlinkofficial

Smart contracts need to be able to connect to real world data & APIs. Chainlink is the middleware that enables blockchain to be connected to the real world. This video describes how to get data from httpget requests, httppost requests, and a number of other methods into your smart contract. It also goes into exactly how it plays out on the Ethereum chain.

Chainlink is a decentralized oracle network that enables smart contracts to securely access off-chain data feeds, web APIs, and traditional bank payments. Chainlink is critical to connecting the blockchain ecosystem to the rest of the world.

Resources from the video:
Note: Ropsten is currently broken, please use Kovan or other testnet: https://remix.ethereum.org/#version=soljson-v0.6.7+commit.b8d736ae.js&optimize=false&evmVersion=null&gist=2324e6830b66ea954b674748b7676c58
Remix Code from the video (with notes): https://remix.ethereum.org/#version=soljson-v0.6.2+commit.bacdbe57.js&optimize=false&gist=9507bdea4570e56067a0ab0ecb351b67&evmVersion=null
Node listing service: https://market.link/

Learn more:
Chainlink Documentation for this video: https://docs.chain.link/docs/request-and-receive-data
Connect any API to your smart contract : https://blog.chain.link/apis-smart-contracts-and-how-to-connect-them/
Adapters documentation: https://docs.chain.link/docs/adapters
Initiators documentation: https://docs.chain.link/docs/initiators

Learn more about Chainlink :
Documentation: https://docs.chain.link/docs/getting-started
Discord: https://discordapp.com/invite/aSK4zew - Very active and developer focused!
Website https://chain.link
Building DeFi Applications: https://defi.chain.link/
Twitter https://twitter.com/chainlink
Telegram https://t.me/chainlinkofficial

Chainlink is an infrastructure designed to be unlimited in how customizable it can be. External adapters are open sourced packages that allows Chainlink nodes to transform and receive data however they like. With external adapters you can do:
1. API Authentication (keep private API password keys private)
2. Private, low latency, and/or high throughput off-chain computation to save gas.
3. Write data to other blockchains (interoperability).
4. Any desired functionality that isn’t covered with the core adapters
This allows your solidity smart contracts to have access to data that they never would have before.

This video goes over:
1. What an external adapter is
2. How to build one
3. Who should host it
4. How to use one

Blog post: https://blog.chain.link/build-and-use-external-adapters/

Chainlink is a decentralized oracle network that enables smart contracts to securely access off-chain data feeds, web APIs, and traditional bank payments. Chainlink is critical to connecting the blockchain ecosystem to the rest of the world.

Code setup:
Install Yarn: https://classic.yarnpkg.com/en/docs/install/
Install nodejs: https://nodejs.org/en/download/
Nodejs External Adapter Template: https://github.com/PatrickAlphaC/CL-EA-NodeJS-Template
Nodejs External Adapter Template with the completed weather API code: https://github.com/PatrickAlphaC/CL-EA-NodeJS-Template/tree/weather-api
External adapter documentation: https://docs.chain.link/docs/external-adapters
Learn more about Environment Variables: https://www.twilio.com/blog/2017/01/how-to-set-environment-variables.html

Remix (kovan) from ending:
https://remix.ethereum.org/#version=soljson-v0.6.6+commit.6c089d02.js&optimize=false&gist=f856530b20943e92ed6cc69c1285cdfe&evmVersion=null

Important Commands/APIs:
curl -X POST -H "content-type:application/json" "http://localhost:8080/" --data '{ "id": 0, "data": { "from": "ETH", "to": "USD" } }'

API:
https://min-api.cryptocompare.com/data/price?fsym=ETH&tsyms=USD

Node Listing Service:
Market.link: https://market.link/

APIs used:
OpenWeatherMap: https://openweathermap.org/
Alpha Vantage: https://www.alphavantage.co/
CryptoCompare: https://www.cryptocompare.com/

Learn more about Chainlink :
Documentation: https://docs.chain.link/docs/getting-started
Discord: https://discordapp.com/invite/aSK4zew - Very active and developer focused!
Website https://chain.link
Building DeFi Applications: https://defi.chain.link/
Twitter https://twitter.com/chainlink
Telegram https://t.me/chainlinkofficial