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API reference / Changelog

API changelog

Every change to the Kintsugi API and every release, newest first. Breaking changes carry the Breaking change mark. Tenanted releases are dated, and you choose one with the Api-Version header.

Changes

2026-10-05

Breaking changes
Requires a unique name when a portfolio creates an organizationBreaking change
Breaking changeOrganizations

When a portfolio credential creates an organization with POST /organizations, the name must now be unique, ignoring letter case. A name already in use answers 409 with code conflict and the message An organization with this name already exists. Before, the 2026-07-21 release accepted any name, including one already in use or one that differed only in letter case, such as acme beside Acme. Creating an organization from a user session without a portfolio is unchanged.

What to do
  • Handle 409 with code conflict by asking for a different name.
  • Do not retry a refused name with different letter case: it is refused the same way.
Sets a billing mode and business websites when a portfolio creates an organization
NewOrganizations

With a portfolio credential, POST /organizations accepts two optional fields. billingMode, PARTNER_MANAGED or CLIENT_MANAGED, sets how the new organization is billed; a portfolio that already has a billing type passes it on and the field is ignored, as it is for a test portfolio. businessWebsites lists the organization's websites: an address without a scheme is saved as https, blank entries and duplicates are dropped, and only http and https addresses are accepted. An invalid address or more than 10 unique addresses answers 422. Sending either field from a user session that is not acting for a portfolio also answers 422.

Adds filing metrics to the organizations list
NewOrganizations

GET /organizations accepts expand=filingMetrics, which adds a filingMetrics object to each organization: totalFilings, filed, pendingApproval (unfiled returns not yet past their due date), overdue (unfiled returns past their due date) and liabilityByCurrency, one { currency, amount } entry per currency. Returns marked do not file are left out of pendingApproval and overdue. Currencies are listed in code order, with returns that have no currency yet last as currency: null, and amounts are decimal strings that are never converted between currencies. An organization with no returns gets zero counts and an empty liabilityByCurrency. Without expand the response is unchanged, an unknown expand value answers 422, and a cursor stays valid with or without expand.

What to do
  • Pass expand=filingMetrics to get each organization's filing status in the same call as the list.

Releases

2026-07-21

LatestTenanted API

Introducing the Tenanted API

A fresh foundation for building on Kintsugi. The Tenanted API is versioned by date, and you choose the release you build against. It speaks one consistent dialect from end to end: clean paths, camelCase fields, exact decimal amounts, and a single error format. And it is built for scale, with one credential reaching every organization it owns.

Compared with v1

Topicv12026-07-21
VersioningThe /v1 path prefixThe Api-Version header, dated YYYY-MM-DD. Optional; without it, a request runs against the launch release
Paths/v1/transactions/transactions
Authenticationx-api-keyApi-Key. Endpoints that manage people accept a signed-in session token instead
Choosing an organizationx-organization-id, required on almost every requestOne credential reaches every organization it owns. Narrow a request with Organization-Id, Connection-Id, or Entity-Id
Field namessnake_casecamelCase
Money and ratesDecimal strings out, numbers or strings inDecimal strings at a fixed scale: amounts to 2 places, rates to 9
TimestampsNo single documented formatRFC 3339 in UTC, always ending in Z
ErrorsShapes vary by endpointOne envelope everywhere: code, message, requestId, and errors
PortfolioNot availablePortfolio and Portfolio Reseller endpoints, for partner accounts

Moving an integration from v1

  1. Send Api-Version: 2026-07-21 with every request, so your integration stays on this release until you decide to move.
  2. Drop /v1 from your paths.
  3. Send your key as Api-Key, and replace x-organization-id with Organization-Id wherever you target one organization.
  4. Rename fields to camelCase, and read every amount as a decimal string, never a float.
  5. Branch on the error code, not the message or the HTTP status, and quote requestId when you contact support.

Creating a transaction answers 202 Accepted straight away, and tax is calculated just after. Check processingStatus before you read the tax totals.

v1

Legacy

The original Kintsugi API, versioned in the path. It remains the default in these docs and is documented exactly as before, so existing integrations can keep running with confidence. New integrations should start on the Tenanted API.

Kintsugi API Changelog