Markline

Open-source, self-hostable documentation framework with first-class OpenAPI, full-text search, and an interactive API playground. A fully open alternative to Scalar and Mintlify.

markline.dev — built with Markline.

Quickstart

npm create @markline@latest my-docs   # scaffold a new project
cd my-docs
npm install
npm run dev                           # preview at http://localhost:3000

Or add Markline to an existing project:

npm install @markline/markline
npx markline init      # scaffold markline.json + sample content in the current dir
npx markline dev

Your project holds only content + config:

my-docs/
├── markline.json      # navigation, theme, branding, API settings
├── docs/              # your pages (*.mdx)
│   ├── index.mdx
│   └── quickstart.mdx
└── api/
    └── openapi.json   # rendered as an interactive API reference

CLI

Command	Description
markline init [dir]	Scaffold a new docs project.
markline dev	Start the dev server against ./markline.json.
markline build	Build a production Node server bundle (Docker / Vercel).
markline start	Serve a production build.
markline export	Build a static HTML site into ./out (any CDN / GitHub Pages / S3).

Hosting

markline init scaffolds ready-to-use deploy configs (Dockerfile, netlify.toml, .github/workflows/deploy.yml).

Static (any CDN / GitHub Pages / Netlify / S3)

markline export   # → ./out

Upload out/ to any static host. The API playground runs in direct-fetch mode (set api.playground.proxy to "never" if your API lacks CORS).

• GitHub Pages — the scaffolded workflow exports and deploys on push to main. Project sites are served under /<repo>, so it builds with MARKLINE_BASE_PATH=/<repo>. For a user/org root site or custom domain, remove that env.
• Netlify — netlify.toml sets command = "npm install && npx markline export" and publish = "out".
• Sub-path hosting — set MARKLINE_BASE_PATH=/prefix so assets and the search bundle resolve correctly.

Node server (Docker / Vercel — full features)

markline build && markline start   # serves on :3000

Enables the playground's server-side proxy for APIs without CORS. The scaffolded Dockerfile builds and serves the site:

docker build -t my-docs . && docker run -p 3000:3000 my-docs

Configuration (markline.json)

Config is read from markline.json (a docs.json is also accepted, for Mintlify-style projects). theme.appearance sets the default color scheme — "dark", "light", or "system" (follows the OS; the default).

{
  "name": "My API",
  "theme": {
    "logo": { "light": "/logo-light.svg", "dark": "/logo-dark.svg", "text": "My API" },
    "colors": { "primary": "#4f46e5", "primaryDark": "#818cf8" },
    "appearance": "system"
  },
  "topbar": {
    "links": [{ "label": "GitHub ↗", "href": "https://github.com/me/repo" }],
    "cta": { "label": "Get started", "href": "/quickstart" },
    "width": "full",        // docs + API reference topbar: "full" (edge-to-edge) | "contained" (centered max-width)
    "homeWidth": "contained" // homepage topbar — independent (defaults to "contained")
  },
  "navigation": {
    "tabs": [
      { "id": "docs", "label": "Documentation", "href": "/", "match": ["__default__"],
        "groups": [{ "group": "Get started", "pages": [{ "href": "/", "label": "Intro" }] }] },
      { "id": "api", "label": "API reference", "href": "/api-reference",
        "match": ["/api-reference"], "openapi": true }
    ]
  },
  "api": {
    "baseUrl": "https://api.example.com",
    "playground": { "mode": "full", "proxy": "auto" }
  },
  "editUrl": "https://github.com/me/repo/edit/main",
  "analytics": { "plausible": { "domain": "docs.example.com" } },
  "feedback": { "endpoint": "https://example.com/api/docs-feedback" },
  "seo": { "title": "My API", "description": "..." }
}

• topbar.width / topbar.homeWidth — topbar layout: "full" spans edge-to-edge; "contained" centers it to the content max-width. width governs docs + the API reference (default "full"); homeWidth governs the homepage independently (default "contained", so the marketing nav aligns with the hero).
• api.playground.mode — the "Try it" experience: "full" (inline param inputs + live console + API Explorer modal), "inline" (Mintlify-style, no modal), "explorer" (read-only docs + console + Explorer modal, Stripe-style), or "off" (static cURL panel).

Ask AI (BYOK)

Opt-in AI assistant for the API reference — a docked chat panel with "Ask about this section" and source citations. Bring your own key; Markline never ships one. Omit the ai block (or set enabled: false) and there is no AI route, no client weight, and no UI — the framework is unchanged.

"ai": {
  "enabled": true,
  "provider": "openrouter",          // openai · openrouter · together · groq · fireworks · local · openai-compatible
  "baseUrl": null,                   // required for "openai-compatible"
  "model": "anthropic/claude-3.5-sonnet",
  "mode": "proxy",                   // "proxy" (operator key, server) | "byok" (reader key, browser)
  "label": "Ask AI",
  "maxTokens": 1024,
  "rateLimit": { "perMinute": 10 }
}

• mode: "proxy" (Node/Docker/Vercel) — the key lives only on the server in MARKLINE_AI_KEY (never markline.json, never NEXT_PUBLIC_*). Requests go through the built-in /api/ai route, which is dropped in static export. ⚠️ A public site with a proxy is an open relay to your paid LLM — the route ships with origin checks and a per-IP rate limit, but enabling proxy mode on a public site spends your budget; tune rateLimit and maxTokens.
• mode: "byok" — the reader pastes their own key (stored in their browser) and calls the provider directly. Works on pure-static hosting; the operator spends nothing.
• One transport speaks the OpenAI /chat/completions shape, so any OpenAI-compatible vendor works via the provider preset or a baseUrl.

API reference content (MDX overlays)

The reference is generated from api/openapi.json, but you can layer authored MDX on top — full components (callouts, tables, tabs) included:

api/
├── openapi.json
├── introduction.mdx              # replaces the auto API landing page
├── sections/<tag>.mdx            # rich summary for an OpenAPI tag/resource
└── operations/<operationId>.mdx  # extra prose on a single operation page

• sections/<tag>.mdx renders as the resource intro on the reference landing (Stripe-style), overriding the OpenAPI tag description. The filename is the slugified tag (e.g. Payment Methods → payment-methods.mdx).
• operations/<operationId>.mdx renders between the endpoint path and the auto-generated parameters on that operation's page.
• editUrl — adds an "Edit this page" link; the page's content-relative path is appended (e.g. docs/quickstart.mdx).
• analytics — opt-in plausible, googleAnalytics (measurementId), or posthog (apiKey, apiHost).
• feedback.endpoint — the "Was this page helpful?" widget POSTs { answer, reason, comment, path } here (logs to console when unset).

Versioning

Declare multiple versions to get a version switcher in the topbar. The first version is the default and is served unprefixed; others are served under their id and read content from <id>/docs/.

"versions": [
  { "id": "v2", "label": "v2 (latest)" },
  {
    "id": "v1",
    "label": "v1",
    "navigation": { "tabs": [ /* hrefs prefixed with /v1 */ ] }
  }
]

my-docs/
├── docs/            # v2 (default)  -> /quickstart
└── v1/
    └── docs/        # v1            -> /v1/quickstart

Localization (i18n)

Identical mechanism to versioning, via i18n.locales. The first locale is the default (unprefixed); others are served under their id with content in <id>/docs/ and their own (translated) navigation. A topbar language switcher appears automatically. A project uses versions or locales (not both).

"i18n": {
  "locales": [
    { "id": "en", "label": "English" },
    { "id": "es", "label": "Español", "navigation": { "tabs": [ /* /es hrefs */ ] } }
  ]
}

my-docs/
├── docs/            # en (default)  -> /quickstart
└── es/
    └── docs/        # es            -> /es/quickstart

Features

• Config-driven navigation, theming, and branding — no code to fork.
• MDX content with server-side syntax highlighting (Shiki).
• First-class OpenAPI: operation pages, schema tables, sample requests/responses.
• Interactive API playground ("Try it") on every endpoint.
• Static full-text search (Pagefind) — zero search infrastructure.
• Dark mode, table of contents, responsive layout.

Authoring components

Available in any MDX page without an import:

• Callouts — <Note>, <Info>, <Tip>, <Check>, <Warning>, <Danger>
• Layout — <Card>, <CardGroup cols={2}>, <Steps> / <Step title>
• Interactive — <Tabs> / <Tab title>, <AccordionGroup> / <Accordion title>
• API — <ParamField path|query|header|body type required>, <ResponseField>

<Note>Heads up — this is worth knowing.</Note>

<Steps>
  <Step title="Install">Run `npm install @markline/markline`.</Step>
  <Step title="Develop">Run `markline dev`.</Step>
</Steps>

License

MIT