@proofmeter/sdk

Signed usage receipts for AI systems. Patent Pending.

ProofMeter signs what an AI system used (tokens, API calls, compute), then lets authorized parties apply the correct cost view — public estimates, private contract rates, usage-only mode, or future invoice reconciliation.

Install

npm install @proofmeter/sdk

Quick start

import { ProofMeter } from '@proofmeter/sdk';

const meter = new ProofMeter({
  apiKey: process.env.VS_API_KEY!,
  namespaceId: process.env.VS_NAMESPACE!,
});

// Record a usage event — get a signed receipt
const receipt = await meter.spend({
  provider: 'openai',
  model: 'gpt-4o',
  inputTokens: 1200,
  outputTokens: 300,
});

console.log(receipt.receipt_id);    // rcpt_7f3a...
console.log(receipt.proven_usage);  // { provider, model, units, ... }
console.log(receipt.event_hash);    // sha256:...

// Verify a receipt
const result = await meter.verify({ receiptId: receipt.receipt_id });
console.log(result.valid);          // true

What a receipt proves

• Resource usage was recorded in a structured event
• The receipt payload matches its hash and signature
• The receipt chain and sequence are intact
• The declared price book hash matches the valuation

What a receipt does not prove by default

• The provider's internal bill (unless invoice data is reconciled)
• The customer's private contract rates (unless an authorized price book is applied)
• Actual billed cost (until reconciliation is connected)

API

new ProofMeter(options)

Option	Type	Required	Description
apiKey	string	Yes	VerifiedState API key
namespaceId	string	Yes	Namespace to scope receipts
baseUrl	string	No	API base URL (default: https://api.verifiedstate.com/v1)

meter.spend(options)

Record a usage event. Returns a signed SpendReceipt.

Option	Type	Required	Description
provider	string	Yes	Provider ID (e.g., openai, anthropic)
model	string	Yes	Model name
inputTokens	number	No	Input token count
outputTokens	number	No	Output token count
units	UsageUnit[]	No	Custom usage units (images, compute, etc.)
endpointClass	string	No	Endpoint type (default: chat)
taskId	string	No	Task/run ID for grouping
capabilityId	string	No	Budget capability to debit
metadata	object	No	Arbitrary metadata

meter.verify(options)

Verify a receipt's signature and chain integrity. Returns a VerifyResult.

meter.receipts(filters?)

List receipts for the namespace.

Links

• Receipt Specification
• Trust Boundaries
• Verify a Receipt
• Python SDK (pip install benchd-harness)
• GitHub

License

MIT