# Compatibility What is tested, what is supported but not tested, and what is not supported. "Tested" means a CI job or an integration test in the repository runs against it; the [Stability](https://berkcansavur.github.io/relaybus/stability) policy says how this list changes. ## Runtimes | | Status | Evidence | | ---------------------------- | ------------------------------- | -------------------------------------------------------------------------------------------------------------------- | | Node.js 22 (22.12 and newer) | tested | CI test matrix `22.x` and `24.x` | | Node.js 24 | tested | CI test matrix | | CommonJS and ESM | built and type-checked for both | every package ships `import` and `require` entry points with their own types; `publint` and `attw` check them in CI | | NestJS 11 and 12 | tested | CI job `nestjs compat` re-resolves `@nestjs/*` to each major and runs the typecheck and the `@relaybus/nestjs` tests | | Bun, Deno | untested, not supported | | ## Stores | Store | Versions | Notes | | ------------------- | --------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | PostgreSQL | 13 and newer; integration tests run on 13 and 17 | `pg` is the primary client and the only one with prepared statements. | | `pg` pool or client | tested | `PostgresEventStore({ pool })` | | Kysely | integration tested | `createKyselyExecutor` | | Knex | integration tested | | | TypeORM | integration tested | | | Drizzle | integration tested | | | Prisma | integration tested (Client 5.22, 6.19 and 7.10, `@prisma/adapter-pg`) | Full contract suite on a generated client. Give the store your `pg` pool as well for prepared statements and wake-ups at commit. | | MongoDB | 6.0 and newer, integration tests on 7 | **Replica set or sharded cluster only**: relaybus uses multi-document transactions. A single-node replica set is enough for development. Driver `mongodb` 6 or 7; Mongoose sessions work. | ## Transports | Transport | Tested | Notes | | ------------------------------------------- | --------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Kafka with `kafkajs` 2.2.x | integration tested against a real broker (`confluentinc/cp-kafka:7.5.0`), 2.2.4 | `kafkajs` is **unmaintained**. It stays supported and is the default `client`; prefer Confluent for new services. | | Kafka with `@confluentinc/kafka-javascript` | integration tested against the same broker, 1.11.0 (KafkaJS-compatible API) | **Recommended**: maintained and librdkafka based. Pass `client: 'confluent'`; the transport puts its settings in the `kafkaJS` blocks and follows the group through `rebalance_cb`. Peer range `^1.11.0`. See [Choosing a client](https://berkcansavur.github.io/relaybus/packages/kafka#choosing-a-client). | | RabbitMQ | integration tested on RabbitMQ 4 (`rabbitmq:4-alpine`); 3.13 or newer is required | **Quorum queues** are used for the queue and the dead-letter queue. `amqplib` 0.10 or newer. | ### Codecs | Codec | Kafka | RabbitMQ | | ----------------------------- | -------------------- | -------------------- | | `cloudEventsBinary` (default) | tested, golden bytes | tested, golden bytes | | `cloudEventsStructured` | tested | tested | | `jsonEnvelope({ ... })` | tested | tested | | `{ encode, decode }` (custom) | tested | tested | ## Explicitly unsupported These are not planned for the current release line; no store or transport exists for them. | | Why / what to use | | ------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | MySQL, SQL Server, SQLite | No store. relaybus needs `SELECT ... FOR UPDATE SKIP LOCKED`-style claims, advisory locks and a transactional outbox in your database; PostgreSQL and MongoDB are the stores. | | MongoDB standalone | No multi-document transactions. Use a replica set. | | Amazon SQS and SNS, NATS, Google Pub/Sub, Redis Streams | No transport. Implement the small `Transport` interface (`publish`, `subscribe`, `close`) yourself if you need one; it is not tested by relaybus. | | Bun, Deno | Untested. | ## Serverless and short-lived processes relaybus delivers from a long-running dispatcher: it claims deliveries on a poll and, on PostgreSQL, wakes on `LISTEN`/`NOTIFY`, and it holds leases while a handler runs. A process that is frozen or killed between requests cannot do that. - **Publishing from a function works**: publish inside your database transaction and let the commit make the event durable. Set `dispatcher: { enabled: false }` in the function and run the dispatcher in a long-running worker ([Tuning](https://berkcansavur.github.io/relaybus/tuning)). - **Dispatching from a function** is possible only by calling `bus.runOnce()` per invocation (one batch) and finishing before the platform freezes the process. Expect higher latency, no `NOTIFY` wake-ups, and leases that expire when an invocation is cut short, which makes the delivery run again (at-least-once holds). - Behind a connection pooler in transaction mode, use the settings in [Tuning](https://berkcansavur.github.io/relaybus/tuning) (`wakeUp: 'poll'`, `preparedStatements: false` where needed). ## Where this is checked CI (`.github/workflows/ci.yml`): `quality` (Prettier, ESLint, typecheck, performance budgets), `test` on Node 22 and 24 with 100 % coverage thresholds, `build` (all packages, `publint`, `attw`), `nestjs-compat` on NestJS 11 and 12. Integration tests start their databases and brokers with Testcontainers.