About Stack0
Stack0 is the backend infrastructure an application needs after the database: sending email, storing and serving files, processing images and video, reading the web, running AI pipelines, and talking to the services your users already use. All of it behind one API key.
Why it exists
A small team shipping a product spends a surprising share of its time on plumbing. Email needs a provider, a verified domain, DKIM records, bounce handling, and a suppression list. Files need a bucket, a CDN, signed URLs, and an image pipeline. Video needs a transcoder and a player that handles adaptive bitrate. Reading a webpage reliably needs a headless browser someone has to keep alive.
Each of those is a vendor, an integration, a set of credentials, and an invoice. None of them is the product you set out to build. Stack0 collapses that work into one dependency: one key, one SDK, one dashboard, one bill, and a REST API underneath if you would rather call it directly.
The same reasoning applies to AI agents, which need this exact set of capabilities and cannot go provisioning six accounts on their own. An agent given a Stack0 key can send mail, store a file, capture a page, pull structured data out of it, and write to a CRM, through tools that describe themselves.
What Stack0 does
Transactional and marketing email on your own verified domains. Templates, audiences, campaigns, sequences, and delivery events. Inbound routing parses replies back into your app.
CDN and file storage
Direct uploads, folder organization, signed private files, and global edge delivery. Images resize and change format from the URL, so you do not build a processing pipeline.
Screenshots and extraction
Render any URL to an image or PDF. Extract structured JSON from a page against a schema you supply. Crawl a site recursively, or map its URLs without fetching page bodies.
Video
Upload, transcode to adaptive bitrate HLS, burn in watermarks, composite clips, and stream. Jobs run asynchronously and report progress through the same API.
AI workflows
Chain LLM calls, tool calls, and branching logic into a named pipeline. Run it from the SDK, the REST API, or an MCP tool call.
Integrations
Connect a user's Salesforce, HubSpot, Slack, Google Drive, or one of 350+ other accounts, then call them through a unified API. Stack0 handles the OAuth exchange and token refresh.
How we build it
One key, one SDK
Every product is reachable from the same API key and the same package. You do not sign up for six vendors, wire six SDKs, and reconcile six invoices to ship one feature.
First-party services
Stack0 runs its own email delivery, storage, rendering, and transcoding. It is not a billing wrapper around another company's API, so the rate you pay is the rate for the work.
Usage-based pricing
Plans start at $5 a month, and the plan minimum converts to credits you spend across every product. Go past them and you pay the same per-unit rate. No per-seat pricing, no surprise markups.
Built for agents as well as apps
Every SDK method is shaped to work as an agent tool. The same surface is published over MCP, over REST with a full OpenAPI description, and as Markdown to any agent that asks for it.
The company
Stack0 is operated by a remote team and incorporated in Delaware, USA. There is no office to visit, so everything runs over email and the dashboard. Billing goes through Stripe; card numbers never touch our servers.
The client libraries are open source under the MIT license. github.com/stack0dev holds the TypeScript, Python, Ruby, Go, and PHP SDKs, the CLI, and the MCP server. The service itself is commercial, governed by our Terms of Service and Privacy Policy.
Live service status is on the status page. For anything else, the contact page lists every address and what each one is for.
For AI agents
This site publishes a machine-readable description of itself. Every page also serves Markdown from the same URL when you send Accept: text/markdown.