Running the Server

Learn how to run and setup the JSON-RPC server on Evmos.

Important: You cannot use all JSON RPC methods unless your node stores the entire copy of the blockchain locally. Do you need archives/snapshots of our networks? Go to this section (opens new window).

Introduction

JSON-RPC is provided on multiple transports. Evmos supports JSON-RPC over HTTP and WebSocket.

Requirements

We recommend to use the server with minimum 8-core CPU and 64gb of RAM. You must have ports 8545 and 8546 open on your firewall.

Enable Server

To enable RPC server use the following flag (set to true by default).

Copy evmosd start --json-rpc.enable

Defining Namespaces

Eth,Net and Web3 namespaces are enabled by default, but for the JSON-RPC you need to add more namespaces. In order to enable other namespaces edit app.toml file.

Copy # API defines a list of JSON-RPC namespaces that should be enabled # Example: "eth,txpool,personal,net,debug,web3" api = "eth,net,web3,txpool,debug,personal"

Set a Gas Cap

eth_call and eth_estimateGas define a global gas cap over rpc for DoS protection. You can override the default gas cap value of 25,000,000 by passing a custom value in app.toml:

Copy # GasCap sets a cap on gas that can be used in eth_call/estimateGas (0=infinite). Default: 25,000,000. gas-cap = 25000000

CORS

If accessing the RPC from a browser, CORS will need to be enabled with the appropriate domain set. Otherwise, JavaScript calls are limit by the same-origin policy and requests will fail.

The CORS setting can be updated from the app.toml

Copy ############################################################################### ### API Configuration ### ############################################################################### [api] # ... # EnableUnsafeCORS defines if CORS should be enabled (unsafe - use it at your own risk). enabled-unsafe-cors = true # default false

Pruning

For all methods to work correctly, your node must be archival (store the entire copy of the blockchain locally). Pruning must be disabled. The pruning settings can be updated from the app.toml

Copy ############################################################################### ### Base Configuration ### ############################################################################### # The minimum gas prices a validator is willing to accept for processing a # transaction. A transaction's fees must meet the minimum of any denomination # specified in this config (e.g. 0.25token1;0.0001token2). # ... # default: the last 100 states are kept in addition to every 500th state; pruning at 10 block intervals # nothing: all historic states will be saved, nothing will be deleted (i.e. archiving node) # everything: all saved states will be deleted, storing only the current state; pruning at 10 block intervals # custom: allow pruning options to be manually specified through 'pruning-keep-recent', 'pruning-keep-every', > pruning = "nothing" pruning-keep-recent = "0" pruning-keep-every = "0" pruning-interval = "0"

WebSocket Server

Websocket is a bidirectional transport protocol. A Websocket connection is maintained by client and server until it is explicitly terminated by one. Most modern browsers support Websocket which means it has good tooling.

Because Websocket is bidirectional, servers can push events to clients. That makes Websocket a good choice for use-cases involving event subscription. Another benefit of Websocket is that after the handshake procedure, the overhead of individual messages is low, making it good for sending high number of requests. The WebSocket Server can be enabled from the app.toml

Copy # Address defines the EVM WebSocket server address to bind to. ws-address = "0.0.0.0:8546"

ETH Tx Indexer

The ETH Tx Indexer provides an optional indexer services for Ethereum transactions to optimize JSON RPC performance. This removes the need for Tendermint Tx Indexer to support RPCs which reduces considerably storage costs.

Enable Indexer

To enable the ETH Indexer run the following command

Copy evmosd start --json-rpc.enable-indexer

Index Historical Transactions

If the chain had already started and you need the ETH Indexer to catch up on old transactions, you could run the index-eth-tx command to index historical ETH transactions.

Copy evmosd index-eth-tx backward

After the eth indexer has finished catching up, the Tendermint indexer can be disabled for JSON RPC support.

If you need to index transactions from the last indexed block to the top of the chain, you can run

Copy evmosd index-eth-tx forward

Eth Tx Indexer and State sync

If setting up a node with state sync, you need to first start the node and index at least one block before turning on the eth tx indexer.