http4k Files

Distribution notice - from 1 October 2026, Maven Central receives http4k releases approximately quarterly. maven.http4k.org continues on the normal 1-2 week cadence. Both channels are supported. Background and current status: DISTRIBUTION.md (www.http4k.org)

Changelog:

• http4k-*: Upgrade versions, including possibly breaking OpenTelemetry upgrade (see below)
• http4k-core: [Break - Java only] Body.EMPTY is no longer a static field. Java callers should use Body.getEMPTY() instead.
• http4k-connect-ai-openai-*: [Break] OpenAIModels updated to current models.
• http4k-ops-opentelemetry: [Possible Break] OpenTelemetry 1.67 returns no-op tracers when the SdkTracerProvider has no span processors (including when no tracer provider is set at all), so the tracing filters will silently produce no spans. Fix: register a span processor.
• http4k-core: [Possible Break] PriorityList.preferred() (and so content negotiation routing) now follows RFC 9110: options weighted q=0 are never selected, an explicit range overrides a * wildcard, and options of equal weight are selected- http4k-postbox: New ScheduledPostboxProcessing replaces the now-deprecated PostboxProcessing. More testable and allows for external scheduler to be used (eg. time4k DeterministicScheduler for tests).
• http4k-template-thymeleaf: [Unlikely break] ThymeleafTemplates.Caching/HotReload now canonicalize the resolved template path.
• http4k-core: [Fix [#1630]] Class initialization deadlock between Body and MemoryBody
• http4k-ai-llm-typesafe: [New module!] Decide implementation backed by the TypeSafe AI "System One" API.
• http4k-ai-llm-core: New Decide interface for structured decisions (choice, score, yes/no questions with probabilities) evaluated against a piece of state.
• http4k-connect-ai-openai-*: Support for the Decisions API (POST /v1/decisions, gpt-6-luna) in the client and FakeOpenAI, with a pluggable DecisionAnswerer.
• http4k-ai-llm-openai: Decide implementation backed by the OpenAI Decisions API, including image input.
• http4k-ai-llm-core: ModelParams gains an optional reasoningEffort (new ReasoningEffort value type in http4k-ai-core).
• http4k-realtime-core: Fix SSE so that routed requests are passed through to the Sse objcet
• http4k-realtime-core: ServerFilters.CatchAllSse (and so PolyFilters.CatchAll) now also catches exceptions thrown by the SSE consumer. in server (offered) order rather than client header order.
• http4k-testing-webdriver: PageBehaviour can be built from the browser's handler
• http4k-testing-webdriver-datastar: Supports data-init, page-relative action URLs, cookies on actions, and live (unbounded) event streams.