The lodestone

Every design decision in Relaystation is judged against one use case:

An AI agent makes one HTTPS call with a payload and a payment, gets back a result, and never created an account.

We call that the lodestone. It is the case that points the way; if a feature would make it harder, the answer is no.

Why it matters

The agent economy does not look like the SaaS economy. An agent has no inbox to confirm, no phone to verify, no browser to click through a checkout. It has a process, a config, and a private key. Anything that demands interactive identity verification is a wall the agent cannot climb.

Most infrastructure was not built for that. A monthly plan does not fit a script that runs once. An OAuth signup does not fit a program with no human attached. Pay-per-call with a wallet does.

What the lodestone buys you

The wallet is the identity. You do not register; you sign. The signature on the payment authorization proves who you are, and the same wallet address ties together everything you do later — every file you convert, every document you send for signature, every baton you create, every charge on your ledger. Come back a month later with the same key and your history is intact.

It also means you pay only for what you use. One call, one charge, no relationship.

The shape of a lodestone call

One POST to any product endpoint — a PDF op, a media convert, an LLM task, a baton create — carries three things: the payload (whatever that op accepts), a signed payment header (a USDC or EURC authorization), and an Idempotency-Key (so a retry is safe). The response carries the result and a PAYMENT-RESPONSE receipt. No prior call, no session, no account.

That is the whole contract — and it holds across the platform: files over 4 MB ride the free scratch tier with the same wallet identity, and nothing on this path ever requires an account or a storage product. Developers who prefer a balance and an API key can have that too — see Authentication modes — but the lodestone is the path everything else is measured against.

How sub-cent calls settle (the sawtooth)

On-chain settlement costs gas — more than a sub-cent call is worth — so Relaystation doesn’t settle every penny-scale call on its own transaction. Instead:

• Every x402 call carries a signed authorization for a settlement chunk of $0.01 (the 402 challenge advertises this as maxAmountRequired).
• A call priced at or above $0.01 settles on-chain individually, on its own authorization.
• A call priced below $0.01 draws down from an already-settled chunk off-chain — no new on-chain transaction, no gas, no nonce consumed. When that chunk’s residual is exhausted, the next call settles a fresh $0.01 chunk on-chain, and subsequent sub-cent calls draw from it.

You authorize $0.01 with each call, but you are charged exactly the sum of your actual call prices — never $0.01 per call. On-chain settlement is batched at the chunk; your charges are exact. We call the pattern the sawtooth: settle a chunk, draw it down, settle the next. On common sub-cent ops, a single penny covers around 50 calls before the next chunk settles. Each chunk and draw-down is a ledger row you can audit.