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JSON-RPC Builder

Build JSON-RPC 2.0 request envelopes with method, params, and IDs. Talk to Ethereum nodes and RPC APIs correctly — local building, free, no signup.

100% Local Browser Native

How to Use the JSON-RPC Builder

1. Enter method and params

RPC method with positional or named params.

2. Build envelope

Valid 2.0 shape with ID assigned.

3. Copy and send

Paste into client or curl for the node.

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Frequently Asked Questions

What makes valid JSON-RPC?

jsonrpc:'2.0', method string, params (array or object), and id — in that shape exactly. The builder assembles the envelope; you supply method and params.

Named vs positional params?

Both valid: arrays for positional, objects for named. Ethereum (eth_call) uses positional arrays; check your server's docs.

Batch requests?

Arrays of envelope objects with unique IDs resolve in any order — match responses by id, not position. Build batches for node efficiency.

Do built envelopes upload anywhere?

No — building runs locally in your browser. Nothing leaves your device.

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Last updated October 2026