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CAFE names the Cloudflare, Alchemy, Foldkit and Effect stack

CAFE is a named stack. Each letter has one job.¶

Read the CAFE news and browse the project directory.¶

Maxwell Brown coined the name; Justin Bennett spread it with his template on 8 October 2026. That day, Devin Jameson, Maxwell and Sam Goodwin streamed a CAFE build, and Sebastian Lorenz wrote the explainer people share.¶

A request follows one path. The Alchemy Stack declares every box on it.¶

┌─ Alchemy Stack ──────────────────────────────────┐
│                                                  │
│  Foldkit app (browser)                           │
│      │  HTTP or RPC, typed by a shared schema    │
│      ▼                                           │
│  Worker (Effect)                                 │
│      │                                           │
│      ▼                                           │
│  Durable Object or storage                       │
│                                                  │
└──────────────────────────────────────────────────┘

The browser and the Worker import the same schemas. Alchemy reads the same program to deploy and to test.¶

The canonical example

Effect-TS/cafe is a chat app from the Effect organization. Its README defines CAFE. Sam Goodwin⁷, who wrote Alchemy, built it. Maxwell Brown also commits to it.¶

It shows these patterns:¶

• @cafe/api holds the HTTP and RPC schemas. It may import only effect, so the browser can import it safely. A lint rule enforces this.¶
• The Worker serves an Effect HttpApi. PR #6 moves chat events to Effect RPC over a Cloudflare.RpcDurableObject, one per chat.¶
• The frontend is a Foldkit single-page app. Side effects are Command.define definitions. PR #2 streamed socket frames with Subscription.fromEvent; PR #6 later replaced the socket with RPC.¶
• Story tests check update, Messages, and Commands. Scene tests drive the rendered view. Both are pure.¶
• Live tests deploy the Stack with Test.make from alchemy/Test/Vitest. The end-to-end test drives Chromium through Playwright.¶
• CI deploys one stage per pull request and destroys it when the pull request closes.¶
• stacks/github.ts is an Alchemy Stack that writes the CI Cloudflare credentials as repository secrets.¶
• Configuration comes from effect/Config. Its AGENTS.md forbids process.env.¶
• The repository carries the Foldkit agent skills.¶

Other CAFE apps

Pleat treats a style as a value:¶

• Styles merge by fixed laws.¶
• Every rule compiles to atomic CSS when its module loads.¶
• Recipe variants are typed by Effect Schema¹⁷.¶
• A model that generates UI can choose styles, but it can never write CSS.¶

Jem at Manzanita Research builds actively in the CAFE space: Pleat, foldkit-dials, and foldkit-native.¶

foldkit-dials

Manzanita-Research/foldkit-dials gives a Foldkit app live tuning controls, after DialKit. It is MIT licensed, at version 0.1.0.¶

• The dials are an Effect Schema.¶
• Every dial edit is a Message.¶
• Foldkit DevTools records each edit.¶
• Time travel replays it.¶
• Story and Scene tests can drive it.¶

Its demo deploys with Alchemy. A stacks/github.ts Stack bootstraps its CI credentials, as in cafe.¶

foldkit-dials is a clear example of the Foldkit rule that every change is a Message. A tool that follows the rule gets recording, replay, and tests from the runtime.¶

Where rat-stack sits

rat-stack is a CAFE stack with the fence³⁹ around it. The table compares it with cafe at rat-stack commit 3fb103b.¶

The largest difference is the API surface²³. See one capability, every surface¹⁸ and infrastructure as effects¹⁰.¶

Sources

• Effect-TS/cafe¶
• foldhub/awesome-foldkit, Foldhub’s community list for Foldkit, announced by Taras Kornichuk¶
• Foldkit¶
• Alchemy¶
• Effect¶

Last changed 2026-10-10 in 978dccc. Source on GitHub. Change log.