Producing messages with the Node.js SDK

Last updated: October 17, 2026

Build the canonical envelope with EnvelopeCodec.make, encode it to JSON with EnvelopeCodec.encode, then publish the bytes with your own broker client.

import { EnvelopeCodec } from "@babelqueue/core";

const env = EnvelopeCodec.make(
  "urn:babel:orders:created",
  { order_id: 1042, amount: 99.90 },
  { queue: "orders" },
);

const body = EnvelopeCodec.encode(env); // compact UTF-8 JSON string
// await redis.rpush("queues:orders", body);
//   /  channel.sendToQueue("orders", Buffer.from(body));

CommonJS works too: const { EnvelopeCodec } = require("@babelqueue/core").

encode produces the canonical schema_version: 1 envelope, with meta.lang set to "node":

{
  "job": "urn:babel:orders:created",
  "trace_id": "7b3f9c2a-e41d-4f88-9b2a-1c0d5e6f7a8b",
  "data": { "order_id": 1042, "amount": 99.90 },
  "meta": { "id": "f1e2d3c4-b5a6-4789-90ab-cdef01234567", "queue": "orders", "lang": "node", "schema_version": 1, "created_at": 1749132727000 },
  "attempts": 0
}

Extension (meta) keys

Pass your own meta keys through the meta option of EnvelopeCodec.make:

const env = EnvelopeCodec.make(
  "urn:acme:orders:created",
  { order_id: 1042 },
  { queue: "orders", meta: { ext: { acme: { tier: "gold" } } } },
);

make throws InvalidEnvelopeKeyError when meta collides with a core key (id, queue, lang, schema_version, created_at) or a forbidden key (meta.max_retries, meta.attempts, meta.source, meta.ts); its pointer holds the RFC 6901 pointer of the key. encode throws the same error for any non-canonical key still on the envelope (top-level timestamp or urn, or a forbidden meta key).

Keep vendor data under a single meta.ext.<vendor> block and use snake_case keys (ADR-0031). The entries are written next to the core meta keys and survive every retry, dead-letter and redrive hop. See Extension keys in the envelope spec.

Next: Consuming messages.