# tuppence.ai

> Tuppence is a payments API for developers and AI agents, built on Stripe: UK card payments through hosted checkout, payment links and subscriptions, plus metered usage billing from prepaid credit (meters, auto top-up, HTTP 402) and an MCP server. Amounts are integers in pence; every POST takes an Idempotency-Key. Pricing is set by the merchant's country of registration: UK from 0.79% per card payment (Amex +1%, commercial +2%, foreign-issued +2%, surcharges stack; no fixed fee), US 2.49% + 20¢ on every US-issued card (foreign +1.5%); other territories on the rate card. No monthly fee or minimum. Holding a Tuppence card adds cashback (UK 0.89%, US 1%). In early access: test mode is open, live payments by waitlist.

## For agents

- [SKILL.md](https://tuppence.ai/skill.md): how an agent should use Tuppence — rules, auth, and the common tasks with exact requests.
- [Docs index for LLMs](https://app.tuppence.ai/docs/llms.txt): every docs page, one line each.
- [Full docs for LLMs](https://app.tuppence.ai/docs/llms-full.txt): the whole documentation as one text file.

## Product

- [Online payments](https://tuppence.ai/payments/): checkout, payment links and subscriptions.
- [Checkout](https://tuppence.ai/payments/checkout/): hosted pay pages and the Payments API.
- [Payment links](https://tuppence.ai/payments/links/): a URL or QR code that takes a payment.
- [Subscriptions](https://tuppence.ai/payments/subscriptions/): plans, trials, proration and retries.
- [Metered AI](https://tuppence.ai/metered-ai/): meters, prepaid credit, HTTP 402, MCP and agent tooling.
- [UK pricing](https://tuppence.ai/pricing/) · [US pricing](https://tuppence.ai/pricing/us/) · [Rate card, every territory](https://tuppence.ai/pricing/rates/)

## Docs

- [Quickstart](https://app.tuppence.ai/docs/quickstart/)
- [API reference](https://app.tuppence.ai/docs/reference/)
- [MCP server](https://app.tuppence.ai/docs/mcp/)
- [HTTP 402](https://app.tuppence.ai/docs/http-402/)