# The three operations

> Enrich a transaction, read an enrichment back and declare observation coverage: one page per API operation.

The API exposes three operations, one page each, best read in this order. [Enrich a transaction](https://developer.noryo.app/en-GB/transaction-intelligence/enrich-a-transaction) covers `POST /transactions/v1/enrichments`: the `TransactionInput` body and its closed schema, the `Idempotency-Key` header, the difference between `201` and `200`, and the `signals` and `resolution.policy` blocks to read first.

[Read an enrichment](https://developer.noryo.app/en-GB/transaction-intelligence/read-an-enrichment) explains `GET /transactions/v1/enrichments/{enrichment_id}`: reading back for 30 days, the single `404`, and what is recomputed on read (relationships and series) as opposed to the resolution, which stays immutable.

[Observation coverage](https://developer.noryo.app/en-GB/transaction-intelligence/observation-coverage) presents `POST /transactions/v1/coverage-windows`: declaring what you supplied for an account over a period, so that a missing due date can be read as a miss rather than as an unknown.

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Canonical page: https://developer.noryo.app/en-GB/transaction-intelligence/api-operations