_section: Providers @<providers>

A **Provider** is an abstraction of a connection to the
Ethereum network, providing a concise, consistent interface
to standard Ethereum node functionality.

The ethers.js library provides several options which should
cover the vast majority of use-cases, but also includes the
necessary functions and classes for sub-classing if a more
custom configuration is necessary.

Most users should use the [[providers-getDefaultProvider]].


_subsection: Default Provider @<providers-getDefaultProvider>

The default provider is the safest, easiest way to begin
developing on //Ethereum//, and it is also robust enough
for use in production.

It creates a [[FallbackProvider]] connected to as many backend
services as possible. When a request is made, it is sent to
multiple backends simultaneously. As responses from each backend
are returned, they are checked that they agree. Once a quorum
has been reached (i.e. enough of the backends agree), the response
is provided to your application.

This ensures that if a backend has become out-of-sync, or if it
has been compromised that its responses are dropped in favor of
responses that match the majority.

_property: ethers.getDefaultProvider([ network, [ options ] ]) => [[Provider]]
Returns a new Provider, backed by multiple services, connected
to //network//. If no //network// is provided, **homestead**
(i.e. mainnet) is used.

The //network// may also be a URL to connect to, such as ``http:/\/localhost:8545``
or ``wss:/\/example.com``.

The //options// is an object, with the following properties:

_table: Option Properties

$Alchemy:     [[link-alchemy]] API Token
$Etherscan:   [[link-etherscan]] API Token
$Infura:      [[link-infura]] Project ID or ``{ projectId, projectSecret }``
$Pocket:      [[link-pocket]] Application ID or ``{ applicationId, applicationSecretKey }``
$Quorum:      The number of backends that must agree
              //(default: 2 for mainnet, 1 for testnets)//

|    **Property**    |  **Description**  |
|    //alchemy//     | $Alchemy          |
|   //etherscan//    | $Etherscan        |
|    //infura//      | $Infura           |
|    //pocket//      | $Pocket           |
|    //quorum//      | $Quorum           |

_note: Note: API Keys

It is highly recommended for production services to acquire
and specify an API Key for each service.

The default API Keys used by ethers are shared across all users,
so services may throttle all services that are using the default
API Keys during periods of load without realizing it.

Many services also have monitoring and usage metrics, which are
only available if an API Key is specified. This allows tracking
how many requests are being sent and which methods are being
used the most.

Some services also provide additional paid features, which are only
available when specifying an API Key.

_subsection: Networks

There are several official common Ethereum networks as well as custom
networks and other compatible projects.

Any API that accept a [[providers-Networkish]] can be passed a common
name (such as ``"mainnet"`` or ``"goerli"``) or chain ID to use that
network definition or may specify custom parameters.

_property: ethers.providers.getNetwork(aNetworkish) => [[providers-Network]]

Returns the full [[providers-Network]] for the given standard
//aNetworkish// [[providers-Networkish]].

This is useful for functions and classes which wish to accept [[providers-Networkish]]
as an input parameter.

_code: @lang<javascript>

//_hide: const getNetwork = ethers.providers.getNetwork;

// By Chain Name
//_result:
getNetwork("homestead");
//_hide: delete _._defaultProvider;
//_log:

// By Chain ID
//_result:
getNetwork(1);
//_hide: delete _._defaultProvider;
//_log:

_heading: Custom ENS Contract

One common reason to specify custom properties for a [[providers-Network]] is to override
the address of the root ENS registry, either on a common network to intercept
the [ENS Methods](Provider--ens-methods) or to specify the ENS registry on a
dev network (on most dev networks you must deploy the ENS contracts manually).

_code: Example: Override the ENS registry @lang<script>

const network = {
    name: "dev",
    chainId: 1337,
    ensAddress: customEnsAddress
};


_subsection: Provider Documentation

_toc:
    provider
    jsonrpc-provider
    api-providers
    other
    types