The Ecosystem

The catalog documents eighteen packages, all published at 0.0.50. The open-core expansion added quadkit-ai-llm, quadkit-ai-agents, quadkit-ai-mcp, quadkit-workflow, and quadkit-notification to the thirteen that shipped before. The catalog includes libraries you compose into an app and two tooling packages: quadkit-cli scaffolds and runs projects, while quadkit-testing boots them under test.

Package dependencies vary by family; shared interfaces belong in quadkit-contracts, and the import-boundary checks include explicit exceptions for composites and tracked edges. See Architecture and Compatibility.

Start from the CLI’s api starter, which includes the web layer; add other installed packages as needed.

uv add "quadkit-cli>=0.0.50,<0.1"
quadkit new project my-app --template api
cd my-app
quadkit run

This catalog is the same list as the package sidebar and the landing cards. Canonical URLs live under /packages/{group}/…. Ungrouped /packages/quadkit-* paths redirect here.

Foundation

The container, the lifecycle, and the contracts everything else builds on.

Package	Availability	What it does
`quadkit`	Published	Async-first core: the DI container, application lifecycle, providers, modules, typed config, and the Result model.
`quadkit-contracts`	Published	Protocols, shared types, and the exception hierarchy — zero runtime dependencies beyond typing-extensions.

Web & HTTP

ASGI, routing, middleware, and the Result-to-HTTP bridge.

Package	Availability	What it does
`quadkit-web`	Published	The async web layer: controllers with signature-based binding, middleware pipelines, a Result-to-HTTP bridge, and OpenAPI.
`quadkit-http`	Published	HTTP client with typed Result errors, retries, timeouts, and a pluggable transport for calling other services.

AI & Agents

Model providers, agent loops, tool registries, and Model Context Protocol servers & clients.

Package	Availability	What it does
`quadkit-ai-llm`	Published	Unified async LLM layer: streaming completions, structured outputs, embeddings, cost attribution, and multi-provider adapters.
`quadkit-ai-agents`	Published	Typed agent loops, `@tool` functions, handoffs, human-in-the-loop checkpoints, and structured execution traces.
`quadkit-ai-mcp`	Published	Model Context Protocol servers and clients: stdio and HTTP/SSE transports, tool/resource/prompt bridges, and DI wiring.

Data

Relational and document storage behind repositories.

Package	Availability	What it does
`quadkit-sql`	Published	Async SQL repositories: typed rows, migrations, connection pooling, and a repository base over SQLAlchemy and asyncpg.
`quadkit-cache`	Published	Cache primitives: a Cache protocol, in-memory and Redis backends, stampede-safe single-flight helpers, and TTL invalidation.
`quadkit-storage`	Published	Artifact storage: a BlobStore protocol, local and S3 backends, content-addressed keys, and signed URL helpers.

Events & Notifications

Publish, subscribe, replay, and deliver multi-channel notifications.

Package	Availability	What it does
`quadkit-events`	Published	Event bus, outbox publishing, durable subscriptions, and a timeline/replay API for auditing what happened.
`quadkit-notification`	Published	Multi-channel notifications: email, SMS, push, Slack, and webhook delivery with templates, user preferences, and digest batching.

Infra & Workflows

Background work, durable DAG workflows, and operational visibility.

Package	Availability	What it does
`quadkit-tasks`	Published	Background tasks: a queue, worker pools, retries with backoff, schedules, and an HTTP console for observing runs.
`quadkit-workflow`	Published	Durable workflows, DAG pipelines, state machines, human approval gates, and compensating sagas with checkpoint/resume.
`quadkit-monitor`	Published	Observability: counters, histograms, structured logs, health/readiness probes, and a metrics endpoint.

Security

Identity, sessions, and access control.

Package	Availability	What it does
`quadkit-auth`	Published	Authentication and authorization: API keys, MFA, RBAC, session stores, and login flows wired through the DI container.

Tooling

Scaffold, run, and test a project: the CLI and the testing harness.

Package	Availability	What it does
`quadkit-cli`	Published	The quadkit command line: project scaffolding, generators, a smart runner, and admin commands.
`quadkit-testing`	Published	Test harnesses, fakes, and fixtures that boot the real application in-process.

Choosing packages

A typical web application starts like this:

quadkit new project my-app --template api   # quadkit, quadkit-contracts, quadkit-web
quadkit add web                                 # wire the web section explicitly
uv add --dev quadkit-testing                    # test harness

quadkit add offers providers that are actually installed. A 0.0.50 PyPI install exposes all eighteen published packages.

Staged stacks: Adoption Paths. Dependency rules, extras, and runtime constraints: Compatibility.

Next Steps

Installation — uv add quadkit-cli and scaffold
Your First App — scaffold with the CLI and run
Architecture — the boundary rules that hold the ecosystem together
Adoption Paths — from a hello-world route to a tested service
Compatibility — extras, drivers, and dependency rules