Introduction
Quickstart
About the docs
Concepts
Rationale HTTP Lenses Serverless WebSockets Server-Sent Events
Tutorials
Your first http4k app Deploying an http4k app to AWS Lambda Going native with Graal on AWS Lambda TDDing http4k
How-to guides
Overview Basic: Server as a function Basic: Client as a function Basic: Use a Server backend Basic: Different test-types Basic: Simple routing Basic: Nestable routes Basic: Arrange Filters into Stacks Attach context to a request Configure an OAuth Server Create a custom JSON marshaller Customise a Server backend Deploy WebJars Integrate with OpenAPI Leverage GraphQL Lookup a User Principal Monitor http4k Record & replay HTTP traffic Serve Server-Sent Events Serve Websockets Structure your logs with Events Test using Service Virtualisation Typesafe your API with lenses Secure and auth HTTP services Use a custom OAuth Provider Use a templating engine Use HTML forms Use Multipart forms Self document systems with tests Use Auto Content Negotiation Redoc and Swagger UI Make JSON Faster Make parallel HTTP calls
Reference
Overview Core Server backend Serverless backend HTTP & Websocket clients Typesafe contracts (OpenAPI3) JSON handling Templating Multipart forms Typesafe Configuration Cloud Native Extensions Cloud Events Micrometer OpenTelemetry Resilience4J Failsafe AWS Azure OAuth Digest GraphQL htmx DataFrame Webhooks JSON RPC XML handling YAML handling Testing
Overview Approval Testing Chaos Testing Hamkrest Kotest Service Virtualisation Strikt Tracer Bullet WebDriver
Blog
Overview Meet http4k Typesafe Websockets Typesafe 12-factor config Documenting http4k apps with OpenApi3 Retrospective on v3 Nanoservices Toolbox: Guns for show, knives for a pro http4k v4 - 17 platforms and counting... http4k Platform v5 - New Servers, Loom, TracerBullet, OpenAI plugin SDK and more JCenter Shutdown
Changelog
http4k in action
Performance
FAQ
Getting support
Contribute/support http4k
Code of Conduct
Source Code

http4k Modules overview¶

Core functionality¶

Core Multipart Forms Typesafe Configuration

API styles¶

OpenAPI Contracts GraphQL

HTTP Server Backends¶

Apache 4 & 5 Java-WebSocket Jetty & JettyLoom Helidon (Loom) Ktor CIO & Netty Netty Ratpack SunHttp & SunHttpLoom Undertow

HTTP Serverless Backends¶

Alibaba Function Compute Apache OpenWhisk AWS Lambda Azure Functions Google Cloud Functions Tencent Serverless Cloud Functions

HTTP Clients¶

Apache4 Sync & Async Apache5 Sync & Async Java Fuel Helidon Jetty OkHttp Websocket

Messaging formats¶

Argo DataFrame Gson Gson XML Jackson Jackson XML Jackson YAML JSON RPC Klaxon KondorJson KotlinX Serialisation Moshi

Templating libraries¶

Freemarker Handlebars Pug4j Rocker Pebble Thymeleaf

SDK integrations¶

Security¶

Digest Auth OAuth

Observability & Metrics¶

Micrometer OpenTelemetry

Web Technologies¶

Cloud-Native/Misc¶

Cloud Native extensions Cloud Events Resilience4J FailSafe Webhooks

Testing¶

Approval Testing Chaos Testing Hamkrest Kotest Playwright Strikt Servirtium WebDriver Tracer Bullet