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Attesso is a server-to-server authorization and evidence layer for asynchronous agent actions. Your backend creates a bounded mandate. The end user approves it with a passkey. Attesso evaluates the concrete action your system proposes and signs the result into independently verifiable evidence. Attesso does not execute an action or move money. You keep your own payment provider and bind each authorization to it.

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The complete flow

1

Create a mandate

Convert authenticated end-user intent into a deterministic policy with fixed action, attribute, payment, and time bounds.
2

Collect approval

Create a five-minute approval session and redirect the user to Attesso’s hosted passkey ceremony.
3

Evaluate one action

Submit the exact action your system intends to perform. DENY and INDETERMINATE always fail closed.
4

Execute and close

Execute through your own systems before execute_before. Commit after acceptance, or cancel only after execution is impossible.
5

Verify the record

Retrieve and verify the signed evidence envelope independently of the Attesso dashboard.

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Responsibility boundary

Run the quickstart

One command from a test key to verified evidence.

Understand the model

Mandate states and the single-use guarantee.

Define a policy

The exact v1 constraint language.

Read the API reference

Endpoints, media types, and environments.