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Welcome to Plumb

Plumb is an AI platform that gives you something most AI services don't: a receipt for every answer. A receipt is a small signed record that proves the AI gave you exactly the answer it gave you, at the price it said, from the model it claimed — nothing swapped, nothing changed.

You don't have to take our word for it. You can check the receipt yourself with a few lines of code, or click a button in the explorer and let your browser check it for you.

Pick your starting point

I just want to try it. → Quickstart. Five minutes, one Python script, a real answer with a real receipt.

I want to understand what the pieces are. → How Plumb works. A tour of the platform in plain English.

I want to know what a receipt actually proves. → Receipts explained. What's inside one, why it matters.

I want to run my own Plumb. → Self-hosting. Plumb is open source — you can run your own copy on any Linux server.

The four things Plumb does

Plumb has four parts. You can use any of them, ignore any of them, and they don't interfere with each other.

  • Inference — Ask an AI a question, get an answer. Same interface as the OpenAI SDK, so existing code works with a one-line change.
  • Hub — Upload your own AI models, get a permanent link to them, optionally register them on a public ledger so the world knows they're yours.
  • Memory — Tell Plumb to remember things from one conversation so the next one picks up where you left off. Off by default. You can delete any memory any time.
  • Verification & Pipe — Check that a receipt is real. And if you're building on a blockchain, call Plumb from inside a smart contract.

Who Plumb is for

  • Developers building apps on top of AI who want to prove to their users (or auditors, or each other) that the AI actually said what it said.
  • Businesses with compliance concerns — regulated industries, financial audit trails, legal discovery — where "ChatGPT told me so" isn't good enough.
  • Researchers who want reproducible outputs pinned to specific model versions.
  • Blockchain developers who want AI-powered smart contracts without trusting a single oracle operator.
  • Anyone who wants a self-hostable, OpenAI-compatible AI gateway they can run on a $10 VPS.

What's on the rest of this site

  • Quickstart — try it
  • Architecture — what the pieces are and how they fit
  • Concepts — plain-English explainers for the main ideas
    • Receipts — what the receipt is and why it matters
    • Verification — how anyone can check a receipt
    • Settlement — why receipts end up on a blockchain
    • Pipe — how smart contracts can ask Plumb for an AI answer
  • Python SDK — the reference if you're writing code
  • Self-hosting — run your own
  • API — the developer reference for raw HTTP calls
  • Contracts — the on-chain side

The short version

You've used AI services where you send a prompt, get a response, and have no way to prove that response ever existed. If the provider disappears, changes the model, or denies what it said — you're stuck.

Plumb adds one thing: a signed receipt for every response. The receipt is a small piece of cryptography that says "yes, this answer was produced, by this model, at this cost, at this time." The signature can't be forged. You keep the receipt. Anyone can verify it independently.

That's the whole idea. Everything else on this site is explaining how that simple thing is built and how you use it.