Kafka

Lightweight, dependency-free Kafka broker emulator speaking the Kafka binary wire protocol, so the standard kafkajs client can connect.

Default Connection

parlel-bridge:9092

Supported APIs

Usage

Add the parlel/bridge sidecar to your test compose file. It exposes Kafka at parlel-bridge:9092 and your app connects with the unmodified real kafkajs client — no Parlel code in the app.

include:
  - path: parlel-bridge.yml          # image: parlel/bridge
services:
  app:
    build: .
    env_file: test.env
    depends_on:
      parlel-bridge: { condition: service_healthy }

PARLEL_API_KEY=pk_... docker compose -f docker-compose.test.yml up

Then connect with the real client against the parlel-bridge hostname:

import { Kafka } from "kafkajs";

const kafka = new Kafka({ brokers: ["parlel-bridge:9092"] });

const admin = kafka.admin();
await admin.createTopics({ topics: [{ topic: "events", numPartitions: 3 }] });

const producer = kafka.producer();
await producer.connect();
await producer.send({ topic: "events", messages: [{ value: "hello" }] });

const consumer = kafka.consumer({ groupId: "g1" });
await consumer.subscribe({ topic: "events", fromBeginning: true });

Access via Parlel Sandbox

Kafka uses a binary wire protocol, so parlel_execute does not drive it — point a native client (e.g. kafkajs) at it instead. The parlel/bridge sidecar exposes Kafka at parlel-bridge:9092, tunneling the raw protocol as TCP over the sandbox HTTPS preview proxy via WebSocket, so kafkajs connects to parlel-bridge:9092 unmodified — with just an API key (or localhost if you run the bridge outside Docker and publish ports). No SSH tunnel and no daytona CLI. Because Kafka advertises its broker as parlel-bridge:9092 in metadata (and clients reconnect there), the bridge listens on 9092 so that reconnect lands correctly. A real kafkajs producer and consumer group produce and consume end-to-end.

Surface coverage

This emulator faithfully replicates the API surface most application code and agents exercise. Anything below the supported lines is either an intentional design choice for a fast, zero-cost local emulator (✓ By design) or a candidate for a future release (⟳ Roadmap) — never a silent inaccuracy.

Legend: ✅ fully supported · ◐ accepted (stored, not strictly enforced) · ✓ by design · ⟳ on the roadmap.