Provider API Keys

( TL; DR – sign up for your own API keys with the links below to improve your application performance )

When using a Provider backed by an API service (such as Alchemy, Etherscan or INFURA), the service requires an API key, which allows each service to track individual projects and their usage and permissions.

The ethers library offers default API keys for each service, so that each Provider works out-of-the-box.

These API keys are a provided as a community resource by the backend services for low-traffic projects and for early prototyping.

Since these API keys are shared by all users (that have not acquired their own API key), they are aggressively throttled which means reties occur more frequently and the responses are slower.

It is highly recommended that you sign up for a free API key from each service for their free tier, which (depending on the service) includes many advantages:

Etherscan

Etherscan is an Ethereum block explorer, which is possibly the most useful developer tool for building and debugging Ethereum applications.

They offer an extensive collection of API endpoints which provide all the operations required to interact with the Ethereum Blockchain.

Sign up for a free API key on Etherscan

Benefits:

INFURA

The INFURA service has been around for quite some time and is very robust and reliable and highly recommend.

They offer a standard JSON-RPC interface and a WebSocket interface, which makes interaction with standard tools versatile, simple and straight forward.

Sign up for a free Project ID on INFURA

Benefits:

Alchemy

The Alchemy service has been around a few years and is also very robust and reliable.

They offer a standard JSON-RPC interface and a WebSocket interface, as well as a collection of advanced APIs for interacting with tokens and to assist with debugging.

Sign up for a free API key on Alchemy

Benefits:

Creating a Default Provider

The default provider connects to multiple backends and verifies their results internally, making it simple to have a high level of trust in third-party services.

A second optional parameter allows API keys to be specified to each Provider created internally and any API key omitted will fallback onto using the default API key for that service.

It is highly recommended that you provide an API for each service, to maximize your applications performance.

Passing API Keys into getDefaultProvider
// Use the mainnet const network = "homestead"; // Specify your own API keys // Each is optional, and if you omit it the default // API key for that service will be used. const provider = ethers.getDefaultProvider(network, { etherscan: YOUR_ETHERSCAN_API_KEY, infura: YOUR_INFURA_PROJECT_ID, alchemy: YOUR_ALCHEMY_API_KEY });