---
title: "Create Weld"
method: POST
path: "/api/v1/parts/{part_id}/welds"
tags: ["welds"]
---

# Create Weld

`POST /api/v1/parts/{part_id}/welds`

Create a weld annotation on a part's latest CAD version.

## Path parameters

- `part_id` string, uuid, required

## Request body

- WeldCreate — Payload for ``POST /parts/{part_id}/welds``.
  - `edge_id` string, required — Topology edge ID (e.g. 'edge_7') — looked up in the topology sidecar JSON.
  - `weld_type` string, required — One of WELD_TYPES (fillet, bevel, v_groove, plug, spot).
  - `size_mm` number, required — Weld size / fillet leg length in mm.
  - `length_mm` number, nullable — Seam length; None = full edge.
  - `process` string, nullable — One of WELD_PROCESSES (TIG, MIG, spot, laser, arc) or null.
  - `side` string — ISO 2553 reference-line side (arrow, other, both).
  - `all_around` boolean — Weld wraps the full perimeter (○ symbol).
  - `notes` string, nullable

## Response `201`

Successful Response

- WeldRead — Flattened weld row — built by the service from an OutcomeEvent. Not an ORM passthrough: the source row is an ``OutcomeEvent`` with ``data = {weld_type, size_mm, ...}``; this projection flattens that payload into first-class fields and adds the computed ``is_process_mismatch`` flag.
  - `id` string, uuid, required
  - `part_id` string, uuid, required
  - `cad_file_version_id` string, uuid, nullable, required
  - `edge_id` string, required
  - `weld_type` string, required
  - `size_mm` number, required
  - `length_mm` number, nullable, required
  - `process` string, nullable, required
  - `side` string, required
  - `all_around` boolean, required
  - `notes` string, nullable, required
  - `label` string, required
  - `state` string, required
  - `source` string, required
  - `created_by` string, uuid, nullable, required
  - `created_at` string, date-time, required
  - `updated_at` string, date-time, nullable, required
  - `is_process_mismatch` boolean

## Other responses

- `422` — Validation Error

---

[API](https://skmtc.dev/prototyping/apis/prototyping-io-api.md) · [All operations](https://skmtc.dev/prototyping/apis/prototyping-io-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/prototyping/prototyping-io-api/revisions/f4a0079fbb57/schema)