web3_clientVersion

web3_clientVersion reports which software is running the Ethereum node behind your endpoint and at what version. Mainnet (chain ID 1) is served by several independent execution clients — Geth, Erigon, Reth, Nethermind, Besu — and this method returns a free-form string identifying the one you reached, along with its version and build platform. A typical answer looks like "Geth/v1.12.0-stable-e501b3b0/linux-amd64/go1.20.2". Call it against https://ethereum.therpc.io/YOUR_API_KEY when you want to know what is on the other end. It takes no parameters and the client diversity is the point: no single implementation runs the ETH network, so the string you get back depends on which node answered.

Use cases

Read the client name to decide whether a client-specific feature is worth attempting — for instance, the Erigon-only trace_* methods or Geth's txpool namespace.
Capture the node identity string in diagnostic logs so you can correlate odd behaviour with a particular Ethereum client and version when triaging incidents.

Parameters

This method takes no parameters. Pass an empty array [].

Response

Type	Description
string	Free-form version string, e.g. `"Geth/v1.12.0-stable-e501b3b0/linux-amd64/go1.20.2"`. Format varies by client implementation.

Example request

1curl https://ethereum.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "web3_clientVersion",
7    "params": [],
8    "id": 1
9  }'

Try it live in the Ethereum playground.

Errors & troubleshooting

Common pitfalls

Managed Ethereum endpoints often return a custom or redacted string rather than the raw client build, sometimes to avoid advertising the exact version to potential attackers. Do not assume the string maps to a stock client release.
Treating this as feature detection is fragile. Behind a load balancer your requests may hit different clients, and the string can change between calls. When you actually depend on a method, call it and handle method not found rather than guessing from the version banner.

Supported networks

Mainnet — Chain ID: 1
Sepolia — Chain ID: 11155111