A WireMock simulation of U.S. Bank's REST API — covering domestic transaction initiation, cancellation, reversals, and transaction lookup.
A shared instance of this template runs on a public endpoint — call it right now from curl, an SDK, or an AI agent. Responses are fixed examples and behavior can't be changed; rate limits apply.
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A running WireMock Cloud instance of this template, callable right now from a terminal, a script, or an AI agent.
Endpoints
POST Initiate Domestic ACH Transaction
curl -s -X POST 'https://227wl.wiremockapi.cloud/transactions/domestic' \
-H 'Content-Type: application/json' \
-d '{}'Spec catalog — ACH Originations API (1.3.1) · 5 endpoints
| Method | Path | Summary |
|---|---|---|
| DELETE | /transactions/{transactionID} | Cancel an Incorrectly Posted Transaction. |
| GET | /transactions/{transactionID} | Retrieve Transaction Details by Transaction ID. |
| POST | /transactions/{transactionID}/reversal | Initiate a Reversing Transaction. |
| POST | /transactions/domestic | Initiate Domestic Transactions. |
| POST | /transactions/search | Search transactions. |
Unauthenticated WireMock Cloud demo sandbox for U.S. Bank — not an official U.S. Bank sandbox, and it returns simulated example data only.
Initiating a domestic transaction stamps the moment of submission into the id itself: the response's transactionID is the letters ACH, the current date, and a time component — a fresh value on every call, echoed with status REQUEST_RECEIVED. The lifecycle verbs then operate on that id format. Cancellation answers with TRANSFER_CANCELLED for whichever ACH-format id sits in the path, modeling the recall of an incorrectly posted entry, and the reversal route responds the way ACH actually works: not by editing the original, but by minting a brand-new transaction id for the offsetting entry. Ids outside the ACH format never reach these stubs — they draw the gateway's URI-not-found envelope, numbered 404.2567.3452.
Its shape and its freshness, not its value. Two initiations a second apart produce two distinct ids sharing the ACH-date prefix, so uniqueness-per-submission can be asserted directly, and the format gives idempotency-key logic something realistic to store. Pin an exact id in a fixture file and it will never match again — the clock has moved on.
Their stubs are broken: each response template fills authorization flags from request fields that a lookup request doesn't carry, and the rendered body stops being valid JSON. No request variation fixes it. Treat the two routes as documented-but-unserved in the public sandbox, and build status-polling flows in a private WireMock Cloud copy where the lookup responses are stubs you control.
The cancel matcher checks the id's format, not a ledger — any ACH-shaped value in the path draws the TRANSFER_CANCELLED acknowledgment. That keeps the recall contract testable without requiring a prior initiation in the same session, and it means negative tests for cancelling unknown transactions belong in your own copy, where a 404-on-unknown stub takes two clicks to add.
Because in the ACH network a reversal is a new entry that offsets the old one, not a mutation of it. The mock's reversal response carries a freshly minted clock-based id with REQUEST_RECEIVED status, so reconciliation code learns the right model: track the original and the reversing entry as two records joined by your own reference, the way the settled files will show them. The returns side of that ledger — entries coming back with return reason codes — is reported in the Corporate Account Information template.
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