@effect/platform-node

Patch Changes

• Add typed connection options to NodeHttpClient for unix sockets and mutual TLS.

• Redact sensitive query values in HTTP spans, request inspection and error messages. Also redact URL credentials in client spans, request inspection and errors. Request URLs sent over the wire are unchanged.

  Move AWSAccessKeyId, Signature, sig and X-Goog-Signature from Headers.CurrentRedactedNames to the new UrlParams.CurrentRedactedNames. A custom list replaces these defaults. Add UrlParams.isRedactedName, UrlParams.redact and UrlParams.redactUrl for explicit redaction.

Patch Changes

• Ignore a leading UTF-8 BOM when decoding Node HTTP request and response text, so json no longer fails on BOM-prefixed bodies.

Patch Changes

• Accept address inputs in Dns.reverse and name server inputs in the platform Dns services, and add Dns.nameServerFromInput.

• Add experimental Host, Dns, and AddressResolver modules to effect/net for host parsing, DNS queries, and endpoint resolution, with Node, Bun, and Deno services. DNS operations accept and normalize domain-name strings; endpoint resolution also accepts host:port strings. Add scoped IPv6 literals and host and DNS record schemas, including JSON codecs for records.

  Provide the services explicitly; they are not included in the platform *Services layers. Use NodeAddressResolver.layer.pipe(Layer.provideMerge(NodeDns.layer)) to provide both Node services.

• Add DatagramSocket for UDP on Node, Bun, and Deno, and NetAddress.inetAddressFromNativeUnsafe for runtime-reported addresses.

• Esc now ends terminal key input by default, cancelling CLI prompts with Terminal.QuitError. To keep Esc non-cancelling, pass a shouldQuit predicate to make, such as (input) => input.key.ctrl && (input.key.name === "c" || input.key.name === "d") to quit only on Ctrl+C or Ctrl+D.

• Allow WebSocket clients on Node and Bun to send handshake headers alongside subprotocols through socket constructors, channels, and layers. Preserve browser-compatible constructor calls when headers are not supplied.

Patch Changes

• Tag every module and directly importable export with an explicit @stability. @stability stable follows strict semver, and @stability unstable may receive breaking changes in minor releases.

• Report the 101 status of a successful WebSocket upgrade to server middleware such as HttpMiddleware.logger and HttpMiddleware.tracer, instead of the handler's discarded response status.

• Fix keep-alive requests hanging during graceful HTTP server shutdown.

Patch Changes

• Fix duplex socket readers throwing when a pull is interrupted or its scope closes during a read. Preserve consumed bytes in order across pull interruption and normal EOF, while discarding them when the reader scope closes.

• Create Node HTTP file response streams lazily and destroy them when body consumption ends, avoiding unused open streams when conditional or range handling discards a response.

• Fail refused WebSocket upgrades with SocketError instead of hanging the request fiber, and skip HTTP response writes on destroyed sockets.

Patch Changes

• Close server WebSockets with 1000 on success, 1001 on interruption, or 1011 on failure, while preserving explicit close codes. HTTP request scopes retain the handler's failure exit through response handling and middleware.

• Effect 4.0 is the first stable release of Effect v4. It replaces the 4.0.0 beta and release-candidate series, whose per-release notes remain below under the 4.0.0-beta.* and 4.0.0-rc.* headings. To upgrade from Effect 3, follow the migration guide.

  Packaging and versioning

  • All Effect packages share one version number and are released together. Use the same version of effect and every @effect/* package.

  • @effect/platform, @effect/rpc, @effect/cluster, @effect/cli, @effect/ai, @effect/sql, @effect/workflow, @effect/experimental and similar packages are merged into effect. Separate packages remain only for platforms (@effect/platform-*), SQL drivers (@effect/sql-*), AI providers (@effect/ai-*), framework bindings (@effect/atom-*), OpenTelemetry, Vitest and tooling.

  • Modules such as effect/http, effect/http-api, effect/rpc, effect/cluster, effect/workflow, effect/ai, effect/cli, effect/sql and effect/schema import from effect/<area>. APIs tagged @stability unstable may have breaking changes in minor releases. APIs without a stability tag follow semver.

  • APIs that expose a third-party dependency are tagged @stability unstable, because that dependency's releases can change them. This covers NodeRedis, DenoRedis, BunRedis, @effect/platform-node/Undici and the undici dispatcher APIs, the ws options and re-exports in the platform packages, driver-specific options and clients in @effect/sql-clickhouse, @effect/sql-d1, @effect/sql-libsql, @effect/sql-mssql, @effect/sql-mysql2, @effect/sql-pglite and @effect/sql-sqlite-do, the provider clients, models and generated schemas in the @effect/ai-* packages, @effect/opentelemetry, and the vitest re-export in @effect/vitest.

  • effect has no runtime dependencies.

  • New packages in v4: @effect/platform-deno, @effect/sql-pglite, @effect/ai-openai-compat, @effect/ai-typesafe, @effect/atom-react, @effect/atom-solid, @effect/atom-vue, @effect/openapi-generator and @effect/doctest. @effect/docgen now lives in this repository.

  Core

  • The fiber runtime was rewritten for lower memory use and faster execution, with smaller bundles and better tree-shaking.

  • Services are defined with Context.Service, FiberRef is replaced by Context.Reference, Cause has a flat structure, and many combinators were renamed. See the migration guide for the full list.

  • Software transactional memory is built into Effect.tx, with TxRef, TxQueue, TxHashMap, TxPubSub, TxSemaphore and related Tx* data types.

  • Clock separates wall-clock time from monotonic time.

  • New modules include Semaphore, Latch, LayerRef, ErrorReporter, ByteSize, Newtype and Crypto. Arbitrary is now a native property-based testing module and no longer depends on fast-check.

  Schema

  • Schema v4 is a new implementation with faster parsing, class-based schemas, make constructors on every schema, and effectful decoding with services.

  • SchemaRepresentation powers JSON Schema (Draft-04, Draft-07, 2020-12 and OpenAPI 3.0/3.1) import and export, TypeScript code generation, and AI structured output.

  • SchemaBinary provides a compact binary codec and is the default wire format for cluster transports.

  • Optional JIT and AOT schema compilers are available as experimental modules.

  Platform, HTTP and RPC

  • HttpApi supports typed response headers, streaming and SSE responses, the HTTP QUERY method, HttpApiTest for in-memory testing, and much faster type checking for large APIs.

  • The HTTP modules add static file serving, response compression, rate-limited clients and graceful server shutdown.

  • Socket has a pull-based reader with backpressure and STARTTLS support. Network addresses are modeled by effect/net.

  • RPC serialization is schema-aware and supports server-originated requests and notifications.

  • @effect/platform-deno adds full Deno support. The Node, Bun, Deno and browser packages all provide the platform Crypto service, and the browser package adds IndexedDB support.

  Cluster and Workflow

  • Workflows can be declared with class syntax, and DurableQueue and an in-memory WorkflowEngine are available.

  • Runner memory can be bounded with ShardingConfig limits. Shutdown, entity movement and persisted replies are more reliable.

  SQL

  • @effect/sql-pg uses a built-in PostgreSQL client with pipelining, prepared statements and binary codecs, and no longer depends on pg.

  • @effect/sql-sqlite-node uses Node's built-in node:sqlite and requires Node 22.16 or newer.

  • SqlError exposes structured reasons such as UniqueViolation.

  AI

  • effect/ai adds EmbeddingModel, the DecisionModel classification and rating API, dynamic tools and tool approvals.

  • The MCP server supports protocol versions 2024-11-05 through 2026-07-28, including elicitation, sampling with tools, resource subscriptions and typed tool output.

  • Provider packages cover Anthropic, OpenAI, OpenAI-compatible APIs and OpenRouter.

  CLI, Atom, observability and testing

  • effect/cli adds global flags, command aliases and examples, an interactive wizard mode, and shell completions for Bash, Zsh and Fish.

  • effect/reactivity and the @effect/atom-* bindings add SSR hydration, stale-while-revalidate atoms and serializable RPC and HttpApi queries.

  • The OTLP exporters can be configured with standard OpenTelemetry environment variables, and @effect/opentelemetry aligns logs and spans with the OpenTelemetry specification.

  • @effect/vitest runs property tests with the native Arbitrary module and supports Vitest fixtures.

  Requirements

  • TypeScript 5.9 or newer. TypeScript 7 is recommended.

  • @effect/vitest and @effect/doctest require Vitest 5.

  • @effect/atom-react requires React 19.

  • @effect/platform-deno requires Deno 2.8.3 or newer.

Patch Changes

• Close server-side WebSockets with a code that reflects how the socket run loop exited: 1000 on success, 1001 on interruption, and 1011 on failure.

Patch Changes

• Prevent NodeHttpServer from writing the route's HTTP response onto a connection that was upgraded to a WebSocket connection because stricter clients will interpret those bytes as WebSocket frames, logging "Invalid frame header" and failing the connection with an untyped 1006 error instead of the actual close code that the server sent.