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RPC and Runtime API (Overview for Integrators)

This document describes ways to interact with the Taler node through standardized RPC and specific Runtime APIs.

Node and Protocols

  • Protocols: HTTP/WS JSON-RPC (jsonrpsee)
  • Endpoints exposed by node binary (node/src/rpc.rs)
  • Example of running with open RPC: see node-setup.md

Common RPC (substrate)

  • system_*: chain information, version, events
  • state_*: storage reading, subscriptions
  • author_*: signing/sending extrinsics
  • chain_*: blocks, hashes, finalization subscriptions

Example of getting network name: 

const chain = await api.rpc.system.chain();

Payment and Fees

  • transactionPayment_queryInfo — fee estimation for call.
const info = await api.rpc.payment.queryInfo(txHex);
console.log(info.partialFee.toString());

Runtime API (example areas)

  • Staking Runtime API (pallets/staking/runtime-api): quota/reward calculations.
  • Assets/NFT Runtime APIs (if connected): metadata and balance retrieval.

Calling Runtime API via api.rpc.state.call: 

// method name and SCALE-encoded input structure depend on specific runtime-api
const resultHex = await api.rpc.state.call('StakingApi_methodName', paramsAsHex);

Types and Metadata

  • Use api.registry to register custom types (if there are local types).
  • Metadata version v14+ contains information about pallets/extrinsics/events.

Security

  • In production, restrict RPC: --rpc-methods Safe, CORS/hosts.
  • Don't expose private nodes with Unsafe methods publicly.

Debugging

  • Runtime logs: -lruntime=debug.
  • Event subscriptions: api.query.system.events.

See also: - external-developers.md for dApp examples - partner-pallets.md for integrating custom runtime APIs