Ethereum JSON-RPC API

Name: Ethereum JSON-RPC API API
Brand: Ethereum JSON-RPC API
Availability: InStock

★ Only Publicly Available OpenAPI DocumentDeveloper ToolsMonitoring Observabilitynone1 EndpointsREST

For Agents

Talk to any Ethereum execution client over JSON-RPC 2.0 to read chain state, query transactions, call smart contracts, and broadcast signed transactions.

Quickstart

Get started with Ethereum JSON-RPC API in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"make an Ethereum JSON-RPC call"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with Ethereum JSON-RPC API API.

Query the current block number, block contents, and chain ID from any Ethereum node

Read account balances, transaction counts (nonce), and contract storage at a specific block

Call read-only smart contract methods via eth_call without spending gas

Estimate gas for a pending transaction with eth_estimateGas

GET STARTED

Start building with Ethereum JSON-RPC API API

Explore with Jentic

View OpenAPI Document

Jentic publishes the only available OpenAPI document for Ethereum JSON-RPC API, keeping it validated and agent-ready.

Jentic publishes the only available OpenAPI specification for Ethereum JSON-RPC API, keeping it validated and agent-ready. The Ethereum JSON-RPC API is the standard interface for talking to an Ethereum execution client — Geth, Erigon, Nethermind, Reth, or a hosted node provider such as Infura or Alchemy. All node functionality (querying blocks, transactions, balances, calling contracts, broadcasting signed transactions) is invoked by POSTing a JSON-RPC 2.0 envelope to the node endpoint with a method name like eth_blockNumber, eth_getBalance, eth_call, or eth_sendRawTransaction.

Use Cases

Patterns agents use Ethereum JSON-RPC API API for, with concrete tasks.

★ Wallet balance and transaction history dashboard

A wallet UI assembles balances and recent activity by sending eth_blockNumber, eth_getBalance, and eth_getTransactionByHash JSON-RPC calls to the node URL. ERC-20 balances are read by encoding a balanceOf(address) call and POSTing it via eth_call. Because the JSON-RPC envelope is uniform, the same client speaks to any execution client.

POST {jsonrpc:2.0, method: eth_getBalance, params:[wallet_address, 'latest'], id:1} to / to fetch the wallet's ETH balance, then post an eth_call with the encoded balanceOf(address) data for each ERC-20 holding.

Smart contract event indexer

Indexers replay a smart contract's history by calling eth_getLogs over chunked block ranges with the contract address and topic filter. Each batch returns the logs that match, which the indexer parses into a database to power dashboards or trigger downstream workflows. New blocks are caught up by polling eth_blockNumber or subscribing to newHeads on a WebSocket node.

POST eth_getLogs with fromBlock/toBlock chunks of 5000 and the Transfer topic filter for the target ERC-20 contract, then upsert each log into the indexer's transfers table.

Programmatic transaction submission for a custodial wallet

A custodial wallet signs an Ethereum transaction off-chain and broadcasts it by POSTing eth_sendRawTransaction with the hex-encoded signed payload. The wallet then polls eth_getTransactionReceipt to confirm inclusion and bumps the nonce returned by eth_getTransactionCount before signing the next transaction. Gas is sized via eth_estimateGas to avoid underpricing.

POST eth_sendRawTransaction with the hex-encoded signed transaction, capture the returned hash, then POST eth_getTransactionReceipt(hash) until a non-null receipt is returned.

AI agent answering on-chain questions over JSON-RPC

A research agent answers questions like 'what's the latest balance of vitalik.eth?' by resolving the ENS name off-chain, then posting eth_getBalance and eth_blockNumber JSON-RPC calls through Jentic. The node URL is held in the Jentic vault, so the agent can be pointed at a private RPC provider without exposing the URL or any associated key.

Search Jentic for 'Ethereum JSON-RPC call', execute the operation with method eth_getBalance and the resolved address, then summarise the wei value as ETH.

Key Endpoints

1 endpoints — jentic publishes the only available openapi specification for ethereum json-rpc api, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

POST

Make a JSON-RPC 2.0 call (eth_blockNumber, eth_getBalance, eth_call, eth_sendRawTransaction, eth_getLogs, etc.)

POST

Make a JSON-RPC 2.0 call (eth_blockNumber, eth_getBalance, eth_call, eth_sendRawTransaction, eth_getLogs, etc.)

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

The Ethereum node URL — including any embedded provider key — is stored encrypted in the Jentic vault. Agents call the JSON-RPC endpoint with a scoped execution token; the raw URL never enters the agent's prompt or logs.

Intent-based discovery

Agents search Jentic with intents like 'get an ETH balance' or 'broadcast an Ethereum transaction' and Jentic returns the JSON-RPC POST operation with a schema for the method and params, so the agent does not need to read the execution-API spec by hand.

Time to first call

Direct integration: half a day to wire up JSON-RPC envelope handling, error parsing, and gas/nonce management. Through Jentic: minutes — search, load, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Complementary

Alchemy API

Alchemy hosts Ethereum JSON-RPC nodes plus enhanced data APIs on top of the same protocol.

Use Alchemy when the team wants a managed, low-latency JSON-RPC endpoint with enhanced indexing on top.

Alternative

EtherDelta / ForkDelta API

EtherDelta was a legacy DEX layered on top of Ethereum JSON-RPC; archived and not recommended for new builds.

Use EtherDelta only for historical DEX research; for live exchange access pair Ethereum JSON-RPC with a current DEX.

Complementary

Binance API

Binance can settle off-chain trades whose results are mirrored on Ethereum via JSON-RPC.

Use Binance alongside Ethereum JSON-RPC when an agent has both centralized-exchange and on-chain data needs.

FAQs

Specific to using Ethereum JSON-RPC API API through Jentic.

Why is there no official OpenAPI spec for Ethereum JSON-RPC API?

The Ethereum project does not publish an OpenAPI specification — the JSON-RPC interface is defined in the Ethereum execution-API standards rather than as an OpenAPI document. Jentic generates and maintains this spec so that AI agents and developers can call Ethereum JSON-RPC API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does the Ethereum JSON-RPC API use?

The Ethereum JSON-RPC standard itself does not define authentication; whether you need a key depends entirely on the node host. A self-run Geth/Erigon/Nethermind/Reth node is unauthenticated, while hosted providers such as Infura, Alchemy, or QuickNode require a project ID embedded in the node URL. Through Jentic, the node URL (and any embedded key) is held in the vault.

Can I broadcast a signed transaction with this API?

Yes — POST a JSON-RPC envelope with method eth_sendRawTransaction and the hex-encoded signed transaction as the single param. The response contains the transaction hash, which you can then feed into eth_getTransactionReceipt to wait for confirmation.

What are the rate limits for the Ethereum JSON-RPC API?

Limits depend on the node provider, not on Ethereum itself: a self-run node has no limits beyond hardware, while Infura, Alchemy, and similar set per-second compute-unit ceilings on free and paid tiers. Always check the chosen provider's pricing page and back off on HTTP 429 responses.

How do I read an ERC-20 balance through Jentic?

Search Jentic for 'Ethereum JSON-RPC call'. Jentic returns POST /. Execute it with method 'eth_call', a 'to' field set to the ERC-20 contract address, and a 'data' field containing the ABI-encoded balanceOf(address) call. The response is the hex-encoded uint256 balance, which you decode client-side.

Does this API support WebSocket subscriptions?

This OpenAPI document covers the HTTP JSON-RPC surface only. WebSocket subscriptions (eth_subscribe with newHeads or logs) are supported on most node providers but are out of scope for an HTTP OpenAPI spec; for those, connect directly to the provider's wss:// endpoint.