Supported Languages

OpenBerth auto-detects the language and framework from your project files.

Detection order: Go → Python → Node.js → Static HTML (first match wins).

Node.js

Detection: package.json exists with a start script or a recognized framework dependency.

Default version: Node 20 (override with .nvmrc, .node-version, or engines.node in package.json).

Recognized frameworks:

Framework	Detection	Default Port
Next.js	`next` in dependencies	3000
Nuxt	`nuxt` in dependencies	3000
SvelteKit	`@sveltejs/kit` in dependencies	3000
Vite	`vite` in dependencies	4173
Create React App	`react-scripts` in dependencies	3000
Vue CLI	`@vue/cli-service` in dependencies	8080
Angular	`@angular/cli` or `@angular/core` in dependencies	4200
Generic Node	`start` script in package.json	3000

Package managers: npm, yarn, and pnpm are supported. OpenBerth detects the lock file and uses the correct installer.

Python

Detection: Any of these files: requirements.txt, pyproject.toml, Pipfile, setup.py, setup.cfg, app.py, main.py, manage.py.

Default version: Python 3.12 (override with .python-version, requires-python in pyproject.toml, or runtime.txt).

Recognized frameworks:

Framework	Detection	Default Port
Django	`manage.py` exists	8000
FastAPI	`fastapi` in requirements/pyproject	8000
Flask	`flask` in requirements/pyproject	8000
Generic Python	`app.py` or `main.py` exists	8000

Go

Detection: go.mod exists.

Default version: Go 1.22 (reads the go directive from go.mod).

Build: CGO_ENABLED=0 go build produces a static binary. Runtime uses a minimal debian:bookworm-slim image.

Default port: 8080. Use the PORT environment variable in your code.

Static HTML

Detection: index.html exists (and no other language matched first).

Served directly by Caddy (Alpine). No build step. Supports the /_data/* REST API for storing data without a backend.

Single-file deploy

The CLI can deploy individual files directly — no project setup needed. These are scaffolded client-side into full projects before uploading:

Extension	What happens
`.jsx`, `.tsx`	Scaffolded into a Vite + React project with Tailwind CSS
`.vue`	Scaffolded into a Vite + Vue project with Tailwind CSS
`.svelte`	Scaffolded into a Vite + Svelte project with Tailwind CSS
`.html`	Deployed as static HTML
`.md`	Rendered to a styled static HTML page
`.ipynb`	Rendered to a static HTML page with code cells and outputs

Usage: berth deploy notes.md or berth deploy analysis.ipynb. The scaffolder parses imports to detect npm dependencies and detects Tailwind from class names.

Overriding detection with .berth.json

If auto-detection picks the wrong framework or your project uses a framework OpenBerth doesn’t recognize, you can override detection by adding server-side fields to your .berth.json file:

Field	What it does
`language`	Forces language provider: `node`, `python`, `go`, or `static`
`build`	Overrides the build command
`start`	Overrides the production start command
`install`	Overrides the dependency install command
`dev`	Overrides the dev server command (sandbox mode)

Two modes:

Patch mode — Detection succeeds but you want to change specific commands. Just add the fields you want to override and they’ll be applied on top of the detected result.
Fallback mode — Detection fails entirely. Provide at least language and start, and OpenBerth will construct a working configuration from language defaults plus your overrides.

These fields coexist with CLI fields (name, ttl, memory, port, etc.) in the same .berth.json file. The CLI reads its fields client-side; the server reads the override fields server-side from the uploaded code.