Build, deploy, and understand your app.
Pylon gives you the application framework. Stack0 Build creates the project. Stack0 Cloud runs it. Stack0 Analytics connects product use to revenue. Stack0 APIs add the services that your app needs.
Database, auth, permissions, an API, and live queries in one runtime. MIT licensed and free to self-host.
Generate a real Pylon project that you can download, edit, and deploy through Stack0 Cloud.
Deploy a Pylon project with one command. Cloud provides its URL, database, sign-in, and operations.
Connect pageviews to signups and payments without tracking cookies by default.
Screenshots, web extraction, and 350+ integrations too, through one SDK and one bill.
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What is Stack0?
Most applications need the same things before they need anything specific: somewhere to put data, a way to sign people in, rules about who sees what, and a URL. Pylon is a realtime framework that covers all of it, with the database and sync written in Rust, and Stack0 Cloud runs it for you when you would rather not.
Stack0 Build turns a description into a real Pylon project, not a preview you cannot leave with. It uses Stack0 Cloud for deployment but remains a separate product. Stack0 Analytics connects pageviews, signups, and payments so you can see which channels produce revenue.
Stack0 APIs covers email, file storage and delivery, video, screenshots, web extraction, and 350+ integrations. None of it is a package deal. Pylon runs without Cloud, Analytics works with any stack, and the APIs work from TypeScript, Python, Ruby, or Go.
How it works
Four steps from an empty project to email sending, files on a CDN, and a workflow running in production.
Install one package
Add @stack0/sdk to a TypeScript project, or the equivalent package for Python, Ruby, Go, or PHP. There is nothing to self-host, no bucket to provision, and no separate service to stand up for each capability. The CLI ships separately as @stack0/cli if you would rather drive Stack0 from a terminal or a shell script.
Authenticate once
Create one API key in the dashboard and pass it when you construct the client. That single key covers email, storage, image processing, screenshots, extraction, video, workflows, and every integration. Keys are scoped to an organization and to a sandbox or production environment, so test traffic never touches live data.
Call the service you need
Every product follows the same shape: a typed method, a plain object of arguments, and a typed result. Long-running work such as video transcoding or a site crawl returns a job you can poll, or wait on with a single call. Errors carry a stable code alongside the HTTP status, so retry logic stays simple.
Watch usage in one place
The dashboard shows per-request logs, delivery events, storage totals, and spend for every product on one screen. Billing is usage-based on top of a plan minimum that converts to credits, so an idle month costs the minimum and a busy one is priced at the same per-unit rate.
Built for agents, not just apps
An AI agent needs the same capabilities an application does, and cannot go and open six vendor accounts on its own. Stack0 is one credential that covers all of them, described in formats an agent can read.
Tools that describe themselves
Every SDK method maps to a tool with a JSON Schema for its input and a description of what it does. An LLM can build a function-calling definition straight from the schema, with no hand-written adapter in between and no guessing at argument names.
An MCP server to point a client at
Stack0 speaks the Model Context Protocol over Streamable HTTP at api.stack0.dev/mcp, authenticated with the same bearer key. Claude, ChatGPT, Cursor, and any other MCP client can call 41 tools across email, storage, screenshots, extraction, video, workflows, and integrations without an SDK.
A REST API with a full OpenAPI description
If MCP is not an option, the same surface is REST. The OpenAPI 3.1 document at /openapi.json describes every operation with a unique operation ID, typed parameters, response schemas, error responses, and the rate-limit headers each response carries.
Markdown instead of markup
Every page on this site serves Markdown from the same URL to any client that sends Accept: text/markdown, or appends .md to the path. An agent reading the docs gets the prose, not the navigation, the styles, and the hydration payload.
Everything you need. One SDK.
Pay only for what you use. Plans start at $5/month. No surprises, no long-term contracts.
All services through a single @stack0/sdk import.
Open Source SDKs
Use Stack0 in any language. Every SDK is open source on GitHub.
MCP Server
Give any AI agent access to Stack0 through the Model Context Protocol. Connect it to Claude, Cursor, Windsurf, or any MCP-compatible client.
Install
npx @stack0/mcp
The MCP server exposes every Stack0 service as a tool. Your agent can send emails, upload files, take screenshots, extract data, and call 350+ integrations — all through natural language.
It works with any MCP client: Claude Desktop, Claude Code, Cursor, Windsurf, VS Code, and custom agent frameworks. Just point your client at the server and your agent gains real-world capabilities.
Available tools
FAQ
What is Stack0?
Stack0 is a unified backend SDK that gives you email, file storage, CDN, video processing, screenshots, data extraction, and 350+ third-party integrations through a single package.
What languages and frameworks are supported?
TypeScript, Python, Ruby, and Go. Works with Next.js, Express, Hono, Deno, Bun, FastAPI, Rails, and any AI agent framework that supports tool calling.
How does pricing work?
Plans start at $5/month with usage-based pricing per service. You only pay for what you use. No long-term contracts, cancel anytime.
Can AI agents use Stack0?
Yes. Every SDK method works as an agent tool. Your LLM can send emails, upload files, take screenshots, and call third-party APIs through Stack0.
Do I need separate API keys for each service?
No. One API key, one SDK import. All services are available through the same @stack0/sdk package.
Is there a free tier?
Every plan includes $5 in free credits to get started. No credit card required to sign up.
Start building today
The complete backend for apps and AI agents. One SDK, one bill.
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