How do I mock the Xero Accounting API locally?

Install stunt, add a one-service block to stunt.yaml (adapter: embedded:xero-style), and run stunt up. You get a local, stateful stand-in for Xero Accounting API 2.0 — 15 routes over rest — with no remote account, no network, and no bills.

Is the Xero Accounting API mock data synthetic?

Yes — entirely. The adapter returns generated data only; stunt's adapter lint rejects real-looking secrets and PII at build time. It simulates the shape and behavior of Xero Accounting API (routes, status codes, pagination, webhooks), never real records.

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xero-style

simulates Xero Accounting API 2.0

restadapter v0.1.015 routes

verification

VMVM tier — no SDK suite yet· surface 15 · not implemented 6 · differs 5

use it

# add to stunt.yaml
services:
  xero:
    adapter: embedded:xero-style

# then
$ stunt up

The embedded: source extracts this adapter from the binary — no git clone, fully offline.

how to mock the Xero Accounting API locally

Install stunt, paste the service block above into stunt.yaml, run stunt up — then point your client at localhost instead of Xero Accounting API. It works offline, keeps state across requests and restarts, and every response is synthetic: the route shapes, status codes, pagination, and webhook delivery follow the real Xero Accounting API 2.0 surface — the data is fake, the behavior is real.

backing stores

contactsinvoicesaccounts

api surface (15)

generated from the adapter manifest — exactly what boots, nothing more · covers 4% of the real API's 235 routes (derived from spec Xero-OpenAPI xero_accounting @ 17.0.0)

15 routes

GET/connections

GET/api.xro/2.0/Contacts

PUT/api.xro/2.0/Contacts

GET/api.xro/2.0/Contacts/{id}

PUT/api.xro/2.0/Contacts/{id}

GET/api.xro/2.0/Invoices

PUT/api.xro/2.0/Invoices

GET/api.xro/2.0/Invoices/{id}

DELETE/api.xro/2.0/Invoices/{id}

POST/api.xro/2.0/Invoices/{id}/Payments

GET/api.xro/2.0/Accounts

GET/api.xro/2.0/BankTransactions

GET/api.xro/2.0/Items

GET/api.xro/2.0/TrackingCategories

POST/webhooks

VM-verified behaviors (29)

✓a missing or unknown bearer gets the same 401 TokenExpired envelope; the seeded static token passes
✓GET /connections needs only the bearer and lists the two demo tenants
✓api.xro calls without xero-tenant-id are 400 TenantRequired, and the header matches case-insensitively
✓the seeded static token expires on the virtual clock, and the bearer gate outranks the tenant gate
✓PUT /Invoices sums every line into the totals and echoes each computed LineAmount
✓a single-object body creates one invoice with clock-derived Date and DueDate defaults
✓GET /Invoices/{id} round-trips the stored invoice; unknown ids are the 404 envelope
✓payments accumulate on the ledger and are echoed with their own PaymentID
✓a negative amount is a refund bounded by what was paid
✓over-payment (and an over-refund) is Xero's validation error and leaves the ledger untouched
✓the invoice flips to PAID exactly at a zero balance and then refuses further payments
✓DRAFT invoices are not payable and unknown ids are the 404 envelope
✓DELETE voids to 204 and the record survives with Status VOIDED and a zeroed balance
✓the voided invoice stays listable via the Statuses filter
✓re-voiding, voiding a PAID invoice, and unknown ids are rejected
✓PUT /Contacts creates with Xero defaults and reads back by id
✓the Contacts array upserts by ContactID and ContactNumber, merging over the stored record
✓duplicate active names are Xero's real validation error, in Elements
✓archive is an update: the contact stays readable and releases its name
✓invalid statuses and unknown ids are the plain ValidationError / NotFound envelopes
✓where ANDs clauses in Xero's grammar, and Statuses/InvoiceNumber/ContactID filter the invoice list
✓order sorts by any field in both directions (dates sort as instants)
✓contacts search matches name and email case-blind, while where Name.Contains is case-sensitive
✓the seeded chart of accounts and the static catalogs speak the same grammar
✓page/pageSize walk every contact exactly once, with nextPage only between pages
✓without pageSize paging is off; a page past the end is an empty 200 page
✓a malformed page falls back to page 1 (as-is: no 400)
✓a delivery signed with base64(HMAC-SHA256(key, raw bytes)) is accepted
✓missing, tampered, and wrong-key signatures all answer the 401 envelope Xero requires

Not implemented (6)

No Credit Notes, Quotes, or standalone Payments endpoints
No Journals, Bank Transfers, Employees, or Expense Claims
No Organisations, Currencies, or TaxRates endpoints
Accounts, Items, TrackingCategories, BankTransactions are read-only (GET only)
No attachments or history/notes endpoints
No invoice update, email, or repeating-invoice endpoints

Differs from the real API (5)

No tax-rate registry; line tax is the given TaxAmount, not computed from TaxType
Responses carry a sim-only nextPage field; real Xero signals the last page by item count
GET /connections wraps entries in {connections:[...]} with tenantName; real Xero returns a bare array without it
Malformed page falls back to page 1; real Xero answers 400
nextPage envelope field is a simulator extension; 401 ErrorNumber is the string TokenExpired, not numeric

full scorecard →

want more of the Xero Accounting API surface? adapters are YAML + Starlark — the authoring guide covers adding routes, fixtures, and state machines. Open an issue for anything big first, or just file a PR — merged routes ship in the next release.