Now in public preview · receipts v1

AI answers, proven.

Plumb is the AI platform that gives you a signed receipt for every answer. Check it yourself. Settle it on the blockchain. Never wonder which model you actually paid for.

OpenAI-compatible Self-hostable On-chain settlement
receipt
Verified
Receipt ID
c7f3e0a4-5b82-4a1c-9c8e-1d2e3f4a5b6c
You: Summarize this contract in one paragraph.
AI: This agreement is a standard NDA between …
Model
claude-sonnet-4.5
Cost
482,000 μPLMB
Time
just now
Request
0x7a1b2c9f4d8e…3b1a
Response
0xabcdef012345…c9e4
Signature (ed25519)
0x4f2e71d8c3a9b2…7f1c
Settled on Basetx 0x9c3a…4f28
What you get

AI is a black box. Plumb gives you something to hold on to.

Most AI services hand you an answer and a bill. Plumb's bet is that every answer should leave behind proof — proof you can verify yourself and no one can rewrite. Everything here is built around that idea.

Proof for every answer

Every answer comes with a signed receipt — what you asked, what you got back, which model ran it, what it cost. You check it yourself; no one can fake it or change it later.

Works with your existing code

Plumb speaks OpenAI. Swap one URL and you're done — no new library, no rewrite. The receipt comes along for free.

Backed up on the blockchain

Every couple of minutes, a batch of receipts is committed to Base. Public, permanent, independent of Plumb — so your proof outlives us if it has to.

Self-host in 30 minutes

One Linux VPS. No Docker, no Kubernetes, no vendor lock-in. Own your wallets, your users, your data. Our production instance runs off the same guide.

Smart contracts can ask AI

Pipe lets a Solidity contract request inference and receive a verifiable answer back. Opens up a whole class of AI-powered on-chain apps.

Memory you can delete

Opt-in persistent memory. See exactly what Plumb remembered, why, and when. Delete any of it, any time. No black-box profile.

How it works

Three lines of Python. A receipt you can trust.

If you've ever used an AI API, Plumb works exactly the same way — with one new superpower. Here's the whole loop.

  1. 01

    Ask a question

    Your app calls Plumb the same way it would call OpenAI — same SDK, same shape. Your session is a wallet signature, so there are no passwords to manage.

  2. 02

    Plumb generates a receipt

    The gateway signs a receipt that commits to exactly what you asked, what model ran, what it cost, and what came back. All in one atomic step — no debit without a receipt, no receipt without a debit.

  3. 03

    You verify, anyone can audit

    The receipt rides back with your answer. Check it in one line of code, click a button in the explorer, or let your users do it themselves. Two minutes later it's on-chain forever.

hello.py
# 1. Ask a question
from plumb_sdk import Client
 
c = Client(base_url="https://api.plumbtech.xyz")
resp = c.chat.completions.create(
model="anthropic/claude-sonnet-4.5",
messages=[{"role": "user", "content": "hi"}],
)
 
# 2. Fetch the receipt
rcpt = c.receipts.get(resp.id)
 
# 3. Verify it — one line of math
assert c.verify_receipt(rcpt)
✓ receipt verified — model, cost, timestamp all match
Four primitives

One stack. Four building blocks. No vendor lock-in.

Use what you need, ignore the rest. Everything is OpenAI-compatible where possible, and everything is yours to host.

Verifiable chat completions

Inference

Drop-in OpenAI-compatible endpoint. Every response signed, every batch settled on-chain.

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Content-addressed model registry

Hub

Upload ONNX, GGUF, or safetensors. Every model gets a permanent cryptographic address.

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On-chain AI oracle

Pipe

Smart contracts can request inference and receive a verifiable answer. AI meets Solidity.

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Persistent, deletable context

Memory

Opt-in memory across conversations. Inspectable, deletable, yours. No black-box profile.

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Live feed

Recent receipts

Real answers from real people, signed seconds ago. Click any one — your browser does the cryptographic check right there.

Browse all →
Verified12s ago
Model
claude-sonnet-4.5
Request
0xabcd1234…000000
0.482 PLMBVerify →
Verified47s ago
Model
gpt-4o-mini
Request
0xdeadbeef…000000
0.1285 PLMBVerify →
Verified1m ago
Model
claude-haiku-4.5
Request
0xcafebabe…000000
0.0632 PLMBVerify →

Five minutes. One receipt. Zero trust required.

The hosted version gives you free test credits the moment you sign in. Or run your own Plumb instance on a VPS for about 30 minutes of setup.