Agentic Payments (MPP)

Get an API key and credits with no human, no signup, no dashboard — pay per top-up with MPP.

Agents can obtain an API key and credits without a human — no signup, no dashboard. Pay a credit top-up over MPP (Machine Payments Protocol) and get an API key back, then use it against the standard OpenAI-compatible API.

The amount is your choice: it defaults to $5.00, and you can pay as little as $1.00 by passing amount_cents in the request body (e.g. {"amount_cents": 100}). The challenge call and the paid retry must quote the same amount — MPP binds the credential to it.

The top-up endpoint offers two payment rails — pay whichever your wallet supports:

• method="tempo" — on-chain USDC on Tempo (chain id 4217)

• method="stripe" — Stripe card / Link Shared Payment Token

Fastest path (Tempo wallet)

If you have a Tempo wallet (tempo wallet login):

tempo request -X POST https://api.lightningrod.ai/v1/mpp/topup

This pays the default $5.00 USDC-on-Tempo challenge and returns credits + an API key automatically. Pass -d '{"amount_cents": 100}' to top up a different amount (min $1.00). Any other MPP-aware client (mppx, link-cli) works the same way — point it at the same URL.

Manual flow (raw HTTP, any MPP client)

1. Request a challenge (no payment)

curl -s -X POST https://api.lightningrod.ai/v1/mpp/topup

Returns 402 with two WWW-Authenticate: Payment header instances — pay whichever rail you can:

WWW-Authenticate: Payment id="...", realm="api.lightningrod.ai", method="stripe", intent="charge", request="<base64url>", expires="2026-01-01T00:00:00Z", description="Lightning Rod Labs credit top-up ($5.00)"
WWW-Authenticate: Payment id="...", realm="api.lightningrod.ai", method="tempo", intent="charge", request="<base64url>", expires="2026-01-01T00:00:00Z", description="Lightning Rod Labs credit top-up ($5.00)"

request is base64url-encoded JSON per the MPP spec (draft-ietf-httpauth-payment); decode it for the exact recipient/amount, or read the machine-readable offers (amount, currency, decimals) in x-payment-info at https://api.lightningrod.ai/openapi.json.

2. Pay and retry with the credential

Your wallet/CLI builds and signs the credential for you. Retry with Authorization: Payment <credential>:

curl -s -X POST https://api.lightningrod.ai/v1/mpp/topup \
  -H 'Authorization: Payment <credential-from-step-2>'

Returns 200:

{"organization_id": "org_mpp_...", "credited_cents": 500, "api_key": "sk_...", "api_key_id": "key_..."}

api_key is minted once — save it.

3. Use the key, and refill when credits run out

Use it as Authorization: Bearer sk_... on POST /v1/openai/chat/completions:

curl -s https://api.lightningrod.ai/v1/openai/chat/completions \
  -H 'Authorization: Bearer sk_...' \
  -H 'Content-Type: application/json' \
  -d '{"model": "foresight-v4", "messages": [{"role": "user", "content": "Will the Fed cut interest rates in 2026?"}]}'

When credits run out, that endpoint returns 402. Call /mpp/topup again with the same key in X-API-Key to refill without minting a new org:

tempo request -X POST https://api.lightningrod.ai/v1/mpp/topup \
  -H 'X-API-Key: sk_...'

See also

• OpenAI API — everything you can do once you have a key

• API reference: Agentic Payments — the /mpp/topup schema