TOLLMINT

An API that quotes its own price and takes payment in the same request. An agent asks what something costs, decides, and pays — in one round-trip. No account. No invoice. Nobody signs up.

IThe gate

Four messages, no humans.

This is the actual exchange, not a diagram of one. The price arrives in the refusal, which is what lets a machine decide without reading documentation first.

1Ask

POST /v1/psych/dark-pattern-detect
{ "html": "<html>…</html>" }

2Price

402 Payment Required
{ "maxAmountRequired": "30000",   // $0.030, in micro-USD
  "payTo":  "0x40Cea136…9703DC9",
  "asset":  "USDC",  "network": "base-sepolia" }

3Pay

POST /v1/psych/dark-pattern-detect
X-PAYMENT: <signed authorization>   // EIP-3009

4Deliver

200 OK
{ "data": { "patterns": [ … ], "regulations": [ … ] },
  "_meta": { "cost": { "quoted": 30000, "charged": 30000 },
             "receipt_id": "rcpt_…", "confidence": 0.86 } }

IIThe ledger

Everything for sale, and what it costs.

Read live from the catalog this site's own API serves, so these prices cannot drift from the ones you are charged. Class B is a dataset we built; C is public data we normalise and stand behind.

Product	Returns	Class	Evidence	Per call
Reading the catalog…

IIIFor machines

Four ways in. All of them free to read.

Discovery never costs anything and never touches our database, so it keeps working through our own outages. An agent that cannot find out what something costs is an agent that buys nothing.

Model Context Protocol

api.tollmint.com/mcp

Remote MCP over Streamable HTTP. 13 tools, every description carrying its own price. Nothing to install.

Machine catalog

/v1/agent/catalog

Every product with price, input schema, cache policy and latency budget. One request, no key.

OpenAPI 3.1

/openapi.json

Generated from the same manifests that serve the calls, so the spec cannot describe a route that does not exist.

Plain language

/llms.txt

The catalog written for a model reading it cold, with the guarantees stated in full.

IVAssay

What is actually true today.

Written plainly because the buyer here is a machine that cannot read between lines, file a complaint, or ask a salesperson what was meant.

TESTNETNOT REAL MONEY

Settlement: Base Sepolia. Testnet USDC has no value. Real payment needs a mainnet facilitator, which is not yet chosen.
Card payment: None. The credit ledger is built and tested; there is no route to buy credits with money yet.
Products live: 11, all deterministic. Two model-backed products are finished but withheld rather than advertised while they have no inference budget.
Failed calls: Never charged. An upstream failure voids the hold. Every error says whether it billed you.
Quoted price: Never exceeded. Metered products hold the ceiling and capture only what was used.
Retries: Never double-charged. Idempotency-Key returns the original response.
Corpus: 61 behavioural effects, each carrying its replication status. Findings that failed to replicate are served labelled, not hidden.
Personal data: None. Company-level only. No person-level contact records, by design and not by omission.