ethers.js/docs.wrm/api/providers/jsonrpc-provider.wrm

_section: JsonRpcProvider  @<JsonRpcProvider> @INHERIT<[[BaseProvider]]> @SRC<providers:class.JsonRpcProvider>

The [JSON-RPC API](link-jsonrpc) is a popular method for interacting
with Ethereum and is available in all major Ethereum node implementations
(e.g. [[link-geth]] and [[link-parity]]) as well as many
third-party web services (e.g. [[link-infura]])

_property: new ethers.providers.JsonRpcProvider([ urlOrConnectionInfo [ , networkish ] ])  @SRC<providers:constructor.JsonRpcProvider>
Connect to a JSON-RPC HTTP API using the URL or [[ConnectionInfo]] //urlOrConnectionInfo//
connected to the //networkish// network.

If //urlOrConnectionInfo// is not specified, the default (i.e. ``http:/\/localhost:8545``)
is used and if no network is specified, it will be determined automatically by querying the
node using ``eth_chainId`` and falling back on ``eth_networkId``.

_note: Note: Connecting to a Local Node
Each node implementation is slightly different and may require specific
command-line flags, configuration or settings in their UI to enable
JSON-RPC, unlock accounts or expose specific APIs. Please consult
their documentation.

_property: jsonRpcProvider.connection => [[ConnectionInfo]]
The fully formed [[ConnectionInfo]] the Provider is connected to.

_property: jsonRpcProvider.getSigner([ addressOrIndex ]) => [[JsonRpcSigner]]  @<JsonRpcProvider-getSigner> @SRC<providers/json-rpc-provider>
Returns a [[JsonRpcSigner]] which is managed by this Ethereum node, at
//addressOrIndex//. If no //addressOrIndex// is provided, the first
account (account #0) is used.

_property: jsonRpcProvider.getUncheckedSigner([ addressOrIndex ]) => [[UncheckedJsonRpcSigner]]  @<JsonRpcProvider-getUncheckedSigner> @SRC<providers/json-rpc-provider>

_property: jsonRpcProvider.listAccounts() => Promise<Array<string>>  @<JsonRpcProvider-listAccounts> @SRC<providers/json-rpc-provider>
Returns a list of all account addresses managed by this provider.

_property: jsonRpcProvider.send(method, params) => Promise<any>  @<JsonRpcProvider-send> @SRC<providers/json-rpc-provider>
Allows sending raw messages to the provider.

This can be used for backend-specific calls, such as for debugging or
specific account management.


_subsection: JsonRpcSigner  @<JsonRpcSigner> @INHERIT<[[Signer]]> @SRC<providers:class.JsonRpcSigner>
A **JsonRpcSigner** is a simple Signer which is backed by a connected
[[JsonRpcProvider]].

_property: signer.provider => [[JsonRpcProvider]]
The provider this signer was established from.

_property: signer.connectUnchecked() => [[UncheckedJsonRpcSigner]]  @<JsonRpcSigner-connectUnchecked> @SRC<providers>
Returns a new Signer object which does not perform additional checks when
sending a transaction. See [getUncheckedSigner](JsonRpcProvider-getUncheckedSigner) for more details.

_property: signer.sendUncheckedTransaction(transaction) => Promise<string<[[DataHexString]]\<32>\>>  @<JsonRpcSigner-sendUncheckedTransaction> @SRC<providers>
Sends the //transaction// and returns a Promise which resolves to the
opaque transaction hash.

_property: signer.unlock(password) => Promise<boolean>  @<JsonRpcSigner-unlock> @SRC<providers>
Request the node unlock the account (if locked) using //password//.


_subsection: JsonRpcUncheckedSigner  @<UncheckedJsonRpcSigner> @INHERIT<[[Signer]]> @SRC<providers:class.UncheckedJsonRpcSigner>
The JSON-RPC API only provides a transaction hash as the response when a
transaction is sent, but the ethers Provider requires populating all details
of a transaction before returning it. For example, the gas price and gas limit
may be adjusted by the node or the nonce automatically included, in which case
the opaque transaction hash has discarded this.

To remedy this, the [[JsonRpcSigner]] immediately queries the provider for
the details using the returned transaction hash to populate the [[providers-TransactionResponse]]
object.

Some backends do not respond immediately and instead defer releasing the
details of a transaction it was responsible for signing until it is mined.

The **UncheckedSigner** does not populate any additional information and will
immediately return the result as a mock [[providers-TransactionResponse]]-like
object, with most of the properties set to null, but allows access to the
transaction hash quickly, if that is all that is required.


_subsection: StaticJsonRpcProvider @<StaticJsonRpcProvider> @INHERIT<[[JsonRpcProvider]]> @SRC<providers:class.StaticJsonRpcProvider>

An ethers Provider will execute frequent ``getNetwork`` calls to ensure
the network calls and network being communicated with are consistent.

In the case of a client like MetaMask, this is desired as the network
may be changed by the user at any time, in such cases the cost of
checking the chainId is local and therefore cheap.

However, there are also many times where it is known the network cannot
change, such as when connecting to an INFURA endpoint, in which case,
the **StaticJsonRpcProvider** can be used which will indefinitely cache
the chain ID, which can reduce network traffic and reduce round-trip
queries for the chain ID.

This [[Provider]] should **only** be used when it is known the network
cannot change.


_subsection: Node-Specific Methods @<JsonRpcProvider--other>

Many methods are less common or specific to certain Ethereum Node implementations
(e.g. [Parity](link-parity) vs [Geth](link-geth). These include account and admin management,
debugging, deeper block and transaction exploration and other services (such as
Swarm and Whisper).

The [jsonRpcProvider.send](JsonRpcProvider-send) method can be used to access these.

- [All JSON-RPC methods](link-json-rpc) (including the less common methods) which most
  Ethereum Nodes support.
- [Parity's Trace Module](link-parity-trace) can be used to trace and debug EVM
  execution of a transaction (requires custom configuration)
- [Geth's Debug Module](link-geth-debug) can be used to debug transactions and
  internal cache state, etc.
- [Additional Geth Methods](link-geth-rpc)
- [Additional Parity Methods](link-parity-rpc)