Node gRPC API

For services that need to process a large volume of blocks or transactions, the node’s gRPC API is faster to consume than the REST API: it returns Protobuf-serialized binary messages instead of JSON, and supports server-streaming for large result sets.

Important

There is no public gRPC endpoint. The public nodes mainnet-node.decentralchain.io and testnet-node.decentralchain.io expose only the REST API over HTTPS; the gRPC ports (6870, 6877) and the BlockchainUpdates port (6881) are not reachable from the internet (checked 2026-10-18). To use gRPC, run your own node with the gRPC extension enabled (see Node Extensions) and connect to it. For the Testnet, see Join the Public Testnet.

Warning

The TypeScript client @decentralchain/node-api-grpc is not published to npm yet (npm view @decentralchain/node-api-grpc returns E404, checked 2026-10-18). This page describes the API in its source (monorepo packages/sdk/node-api-grpc, v2.0.0) so you can see what it will offer. The examples below do not run until it is published.

Installing (once published)

npm install @decentralchain/node-api-grpc

Requires Node.js >= 24 and an ESM environment ("type": "module").

Connecting

Point the client at a node you run yourself. localhost below is that node.

import { mkDefaultChannel, mkTransactionsApi } from '@decentralchain/node-api-grpc';

const channel = mkDefaultChannel('localhost'); // defaults to port 6870
const txApi = mkTransactionsApi(channel);

for await (const tx of txApi.getTransactions({ sender: '31...' })) {
  console.log(tx);
}

mkDefaultChannel(host, options?) accepts a bare hostname (defaults to port 6870), a host:port pair, or a full http(s):// or grpc(s):// URL. Pass Connect transport options (TLS, interceptors, timeouts) as the second argument. If your node’s dcc.grpc.port is not 6870 (the public Testnet’s own nodes use 6877), pass host:port.

APIs

Client factory	Service	Methods
mkAccountsApi(channel)	AccountsApi	getBalances, getScript, getActiveLeases, getDataEntries, resolveAlias
mkAssetsApi(channel)	AssetsApi	getInfo, getNFTList
mkBlockchainApi(channel)	BlockchainApi	getActivationStatus, getBaseTarget, getCumulativeScore
mkBlocksApi(channel)	BlocksApi	getBlock, getBlockRange
mkTransactionsApi(channel)	TransactionsApi	getTransactions, getTransactionSnapshots, getStateChanges, getStatuses, getUnconfirmed, sign, broadcast

Request and response types are re-exported from the protobuf schema package (published today as @decentralchain/protobuf-serialization; the monorepo is renaming it to protobuf-schemas), so importing @decentralchain/node-api-grpc alone is enough.

Blockchain Updates

The BlockchainUpdates API streams block-level events (appends, rollbacks, microblocks) in real time — useful for indexers and services that need to react to chain state as it happens, without polling. It runs on a separate port, 6881, from the rest of the gRPC API. Blockchain Updates explains how to enable it, what each update contains and how to consume the stream reliably.

import { mkDefaultBlockchainUpdatesChannel, mkBlockchainUpdatesApi } from '@decentralchain/node-api-grpc';

const channel = mkDefaultBlockchainUpdatesChannel('localhost'); // defaults to port 6881
const updatesApi = mkBlockchainUpdatesApi(channel);

for await (const event of updatesApi.subscribe({ fromHeight: 1 })) {
  console.log(event);
}

Method	Purpose
getBlockUpdate	Fetch the update for a single height
getBlockUpdatesRange	Fetch updates for a height range
subscribe	Server-streaming subscription to new updates as they happen

See Node Extensions for enabling the gRPC server on a node you operate. BlockchainUpdates is a separate extension in the same module and must be enabled on its own.