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Changelog

API changelog

Within /v1, WALT only makes additive changes — new endpoints, optional fields, enum values and event types — so your code must ignore unknown fields and tolerate unknown enum values. Breaking changes ship as a new major version with 12 months’ notice. Newest entries first.

v1 in the sandbox, error pages, New Build Additive

Partner API v1 is available in the sandbox on request; production access is by arrangement. Base URLs and credentials are provided at onboarding.

  • New Build Residential. asset_type accepts new_build_residential, and properties accept an optional floor_area_sqft (gross internal area in sq ft, 1–1,000,000) on create and update. A new build is valued against local £/sq ft comparables. Tolerate the new enum value when you read properties.
  • API reference synced with the API’s own OpenAPI export: the two fields above, the 413 descriptions on document and call-transcript uploads, and the upload file schema (format: binary). The Postman collection is regenerated from it.
  • Error pages. Every problem type (https://www.underwritinguk.ai/developers/errors/<code>) now opens a page with the HTTP status, what the code means and what to do. All codes are listed on Error codes.
  • Integration guide 1.0. Documents 400 idempotency_key_required, 409 idempotency_in_progress and 409 idempotency_result_unavailable; PDF reports need pii:read as well as reports:read; a JSON body must be sent with Content-Type: application/json; money ranges; sanctions, PEP and adverse-media screens and borrower ID verification are never reused by a re-assessment; decision guard-rails; borrower steps expire after 14 days; the /events settle window; 409 case_closed and 409 conflict; and the detail of the rate limits. The source-of-funds step is marked as not available yet.

v1 specification draft Draft

First public draft of the Partner API, ahead of the sandbox.

  • Published the integration guide (document version 1.0-draft): authentication, conventions, the end-to-end flow, the Decision object, webhooks, borrower actions, sandbox personas, connector methodology and the go-live checklist.
  • Published the OpenAPI 3.1 document exported from the API itself (the same document as GET /v1/openapi.json), including call transcripts, subject reads and the type filter on /events.
  • Published a Postman collection generated from that document: the end-to-end flow with automatic OAuth token handling, plus a request for every operation.
  • The sandbox will run on WALT’s dev environment at https://dev-api.underwritinguk.ai/v1 (DNS pending — your onboarding email gives the current sandbox URL). Production: https://api.underwritinguk.ai/v1.

Field names and behaviours may still change before general availability. Each change will be listed here.