---
title: "Upload registration attachment"
method: POST
path: "/v1/registrations/{registration_id}/attachments"
tags: ["Registrations"]
---

# Upload registration attachment

`POST /v1/registrations/{registration_id}/attachments`

Upload an attachment for a specific registration.

## Path parameters

- `registration_id` string, required

## Headers

- `x-organization-id` string, nullable, required — The unique identifier for the organization making the request

## Response `200`

Successful Response

- Attachment
  - `id` string
  - `created_at` string, date-time — Timestamp when transaction was created in Kintsugi.
  - `updated_at` string, date-time, nullable — Timestamp when transaction was last updated.
  - `related_entity_id` string, required — The unique identifier of the exemption associated with the attachment.
  - `related_entity_type` 'EXEMPTION' | 'REGISTRATION' | 'FILING' | 'FILING_PAYMENT', required
  - `organization_id` string, required
  - `file_name` string, required
  - `mime_type` string, required
  - `file_size_bytes` integer, required
  - `file_location` string, required
  - `file_location_type` 'S3' | 'LOCAL', required

## Other responses

- `422` — Validation Error

## Changes

- **2026-08-29** `6ba4f4c774c3` — 1 info
  - endpoint added
  - …this revision’s changelog is incomplete

[Change history](https://skmtc.dev/trykintsugi/apis/tax-platform/changes/v1/registrations/:registration_id/attachments/post.md)

---

[API](https://skmtc.dev/trykintsugi/apis/tax-platform.md) · [All operations](https://skmtc.dev/trykintsugi/apis/tax-platform/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/trykintsugi/tax-platform/revisions/0be736131b5a/schema)