From a test key to a verified receipt.

Sign in with Google or email and create a key. It negotiates with the sandbox store only and cannot reach a real store or move money.

One command: a sample buyer opens a session, bids, reaches an agreement, checks the signed receipt on your machine, and prints a link to see it in the verifier.

export VALYZEN_API_KEY=vz_pk_test_…   # from step 1

# A sample buyer negotiates the Demo Monitor, verifies the receipt, prints a verify link
uvx valyzen try

# or: pip install valyzen && valyzen try

TypeScript or JavaScript (Node 20 or later, browsers, Deno, Bun)

npm install @valyzen/sdk

import { GatewayClient, verifyReceipt, verifyLink } from '@valyzen/sdk'

const client = new GatewayClient(process.env.VALYZEN_API_KEY, { baseUrl: 'https://api.valyzen.ai' })
const session = await client.openSession('DEMO-MONITOR-27', { agentId: 'my-first-bot' })
while (!session.finished) {
  const edge = session.fairEdgeMinor
  const standing = session.merchantOfferMinor
  if (standing !== null && standing <= edge) await session.accept()
  else await session.offer(edge, { inclusions: session.tableInclusions })
}
const receipt = await session.receipt()
const result = await verifyReceipt(receipt, { allowTest: true }) // sandbox receipts are test mode
console.log(result.ok, result.signedTerms, await verifyLink(receipt, 'https://api.valyzen.ai'))

export VZ_KEY=vz_pk_test_…   # from step 1

# What the sandbox store will negotiate over
curl -s -H "Authorization: Bearer $VZ_KEY" https://api.valyzen.ai/v1/catalogue

# Open a session on the Demo Monitor; the merchant makes the first offer
curl -s -X POST https://api.valyzen.ai/v1/sessions \
  -H "Authorization: Bearer $VZ_KEY" -H "Content-Type: application/json" \
  -d '{"sku":"DEMO-MONITOR-27","buyer":{"agent_id":"my-first-bot"}}'

# Keep session_id and session_token from the reply, then take the offer
export SID=… VZ_ST=vz_st_test_…
curl -s -X POST https://api.valyzen.ai/v1/sessions/$SID/messages \
  -H "Authorization: Bearer $VZ_ST" -H "Content-Type: application/json" \
  -d '{"type":"accept"}'

# The signed receipt
curl -s -H "Authorization: Bearer $VZ_ST" https://api.valyzen.ai/v1/sessions/$SID/receipt > receipt.json

Open the link the trial prints, or paste receipt.json into the verifier. It checks the signature in your browser against the key inside the receipt and Valyzen's published keys; nothing is sent anywhere. Sandbox receipts are marked as test mode: anyone with a test key can make one, so they show the loop works, not that a purchase happened.

Connect an MCP host to https://api.valyzen.ai/mcp and sign in with the same account, then ask it to negotiate the Demo Monitor.

Claude Code

claude mcp add --transport http --client-id 2a7kinrpg29uuc7503j10qqsr7 --callback-port 33418 valyzen https://api.valyzen.ai/mcp

Claude: Settings, Connectors, add a custom connector with that URL; under Advanced settings set the OAuth client id orqs263f7h1feiqhaanq8bli8.

ChatGPT (developer mode): add an MCP server with that URL and OAuth client id 61ojs6dpfsqk62vrttg1hob1b4.

A buyer can send a commitment to its private limit when it opens a session. When you do, the limit stays on your machine and you reveal it only after the session ends. When you do not (the plain requests above, or a chat host), the gateway records the commitment on your behalf, and the receipt says which of the two happened. The sample buyer never sends its limit at all: it only ever sends offers.

The SDKs are open source, Apache-2.0: valyzen-sdk on GitHub.