A Mermaid alternative where diagrams are validated, not just drawn

Mermaid earned its place: text in, diagram out, right inside Markdown. Chiltepin keeps that idea and changes one thing that changes everything — diagrams are typed YAML with a schema, so a validator can prove them right, an AI agent can write them reliably, and CI can fail the build when they drift.

You do not have to rewrite anything first

A ```mermaid fence is converted into a typed Chiltepin block when the file is parsed. Five grammars are covered — sequenceDiagram, flowchart / graph, erDiagram, stateDiagram and pie — and the result validates and renders identically to a hand-written block. Any other Mermaid grammar stays prose, exactly as before, and is never flagged.

So the migration is: keep your fences, run chiltepin check, and let the first structured edit rewrite each one to its canonical tag. The exact supported subset, and what is dropped, is documented rather than implied — reference/mermaid.md. DBML and Prisma fences convert the same way, and chiltepin sync sql | dbml | prisma <file> converts a whole schema file.

The same diagram, side by side

Mermaid:

sequenceDiagram
  Client->>API: POST /orders
  API-->>Client: 201 Created

Chiltepin:

```sequence
id: seq-place-order
title: Place order
actors:
  - { id: Client, name: Client }
  - { id: API, name: Orders API }
messages:
  - { from: Client, to: API, label: POST /orders, kind: sync }
  - { from: API, to: Client, label: 201 Created, kind: response }
```

Chiltepin is more explicit on purpose. Named actors, typed message kinds, and a required id are what make the block checkable: chiltepin check verifies every field, every referenced actor, and every cross-reference between blocks — and fails CI on errors, exactly like a test suite. A Mermaid string that parses is "valid" even when it's wrong.

Where the two tools differ

When Mermaid is still the right call

One diagram in a GitHub README that GitHub renders for free? Use Mermaid — it's the shortest path and we'd pick it too. Chiltepin is for the step after that: when diagrams live inside real documents that need review, validation, theming, and export — and when an AI agent is doing the writing and you need to trust the result. It's the docs-as-code workflow applied to everything visual, not just prose.

Try it without installing anything

The whole editor runs in your browser — open a prefilled template in Studio, or paste your own Markdown into the playground and watch the real pipeline render it. Nothing is uploaded, and there's no signup.