eth_protocolVersion — Polygon JSON-RPC

Status: Available

Returns the current EVM protocol version of the Polygon node as a hex string constant.

POSThttps://triport.io/polygon

Network: Polygon
Scope: polygon_read_rpc
Auth: x-token: $TRIPORT_API_KEY (or Authorization: Bearer)
Rate limit: free — 15 rps · basic — 20 rps · pro — 100 rps · business — 250 rps

Endpoint and plans: Polygon RPC endpoint.

Request

cURLJavaScriptPython

curl https://triport.io/polygon \
  -H "Authorization: Bearer $TRIPORT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_protocolVersion",
    "params": []
  }'

const res = await fetch("https://triport.io/polygon", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.TRIPORT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "jsonrpc": "2.0",
    "id": 1,
    "method": "eth_protocolVersion",
    "params": []
  }),
});
const data = await res.json();
console.log(data);

import os


import requests


resp = requests.post(
    "https://triport.io/polygon",
    headers={
        "Authorization": f"Bearer {os.environ['TRIPORT_API_KEY']}",
        "Content-Type": "application/json",
    },
    json={
        "jsonrpc": "2.0",
        "id": 1,
        "method": "eth_protocolVersion",
        "params": [],
    },
)
data = resp.json()
print(data)

Response

JSON

Example

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": "0x42"
}

eth_protocolVersion returns the protocol version advertised by the Polygon execution layer. On Polygon mainnet (chain ID 0x89 / 137) the underlying client is Bor, which reports a small hex constant — typically 0x42 (66) or 0x41 (65).

The value is effectively static: it only changes across a node software upgrade, so clients may cache it indefinitely after the first successful response. It is most often used as a lightweight capability/identity check during connection setup, not on a hot path.

This is a read method included in the Free trial (polygon_read_rpc) and takes no parameters. One quirk worth knowing: this method is noticeably slower than its sibling network-state reads (eth_chainId, net_version) — the backend recomputes the value rather than serving it from cache — so prefer to call it once and reuse the result.

Parameters

eth_protocolVersion takes no parameters. Pass an empty params array.

——optional

This method accepts no parameters.

Response

Response fields

Field	Type	Description
`jsonrpc`	string	JSON-RPC version, always `"2.0"`.
`id`	number \| string	Echoes the `id` from the request.
`result`	string	EVM protocol version as a hex-encoded integer (e.g. `0x42`).

Errors

Errors use the standard JSON-RPC envelope; see errors.md for the full shape and handling guidance.

Code	Meaning	When it happens
`401`	`trial_expired`	The trial window for the API key has ended.
`403`	`tier_insufficient`	The key's tier is below what this method requires.
`429`	`rate_limited`	The tier's RPS limit (with burst) was exceeded.
`401`	`subscription_expired`	The key's paid subscription has lapsed.
`401`	`unauthorized`	Missing or invalid `Authorization` bearer token.
HTTP `403`	`method_unknown`	Method not found / not enabled for this key.

Examples

JavaScript (fetch)

JavaScript

const res = await fetch("https://triport.io/polygon", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.TRIPORT_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    jsonrpc: "2.0",
    id: 1,
    method: "eth_protocolVersion",
    params: [],
  }),
});


const { result } = await res.json();
console.log(result); // "0x42"

Notes

Cache indefinitely. The value only changes on a node upgrade. Fetch it once per connection and reuse it; avoid calling it in a loop.
Not cached. The backend does not serve this from cache — one more reason to call it once and reuse it.
Related methods: eth_chainId (0x89 for Polygon mainnet) and net_version ("137" as a decimal string) are the better choices for chain-identity checks.
Decoding: parse with parseInt(result, 16) in JS or int(result, 16) in Python.