near_jsonrpc_client

Type-safe NEAR Protocol JSON-RPC client for Dart, generated from the official nearcore OpenAPI spec.

• Platform-agnostic: pure Dart — runs identically on native (AOT: mobile, desktop, server) and web (compiled to JavaScript / WASM).
• Fully generated: every request/response model (343 types) and all 38 RPC methods are produced by tool/generate.dart from the spec — no hand-written drift.
• Auto-maintained: a scheduled GitHub Action re-fetches the spec, regenerates the client, and opens a PR when nearcore changes.

import 'package:near_jsonrpc_client/near_jsonrpc_client.dart';

void main() async {
  final rpc = NearJsonRpcClient(endpoint: 'https://test.rpc.fastnear.com');

  // No-input methods take no arguments:
  final status = await rpc.status();
  print(status.chain_id);                       // testnet
  print(status.sync_info!.latest_block_height); // typed

  // Methods with params take a generated request type:
  final block = await rpc.block(
    RpcBlockRequest.fromJson({'finality': 'final'}),
  );
  print(block.header!.height);

  rpc.close();
}

How it's generated

tool/generate.dart reads tool/openapi.json (a committed snapshot of the nearcore spec) and emits:

• lib/src/models.g.dart — a Dart class for every object schema, a Dart enum for every string enum, a holder for every oneOf/anyOf union, and typedefs for aliases.
• lib/src/client.g.dart — NearJsonRpcClient with one typed method per RPC path.

Regenerate manually with:

dart run tool/generate.dart

Design notes

• Defensive decoding: every model field is nullable. nearcore's spec marks many fields required that can be null/absent in real responses, and the spec evolves — a generated client must decode without crashing.
• Unions (oneOf/anyOf, e.g. NEAR's Rust-tagged enums) are represented as holders exposing the raw decoded json; inspect it for the active variant.
• The client exposes NearJsonRpcClient.specVersion — the nearcore OpenAPI version it was generated from.

Relationship to near_dart

This package is the low-level, generated RPC layer. For transaction signing (ed25519 + Borsh), a high-level Account API, and wallet connect, see near_dart.

License

MIT