---
title: "Stage a private attachment without sending a message"
method: POST
path: "/api/v1/verify_messages/runs/{scenario_run_id}/uploads"
tags: ["verify_messages"]
---

# Stage a private attachment without sending a message

`POST /api/v1/verify_messages/runs/{scenario_run_id}/uploads`

## Request

- Base URL: `https://composal.com` (the document declares no server; this is the origin it was published from)
- URL: `https://composal.com/api/v1/verify_messages/runs/{scenario_run_id}/uploads`
- Auth: API key in cookie `__Host-verify_messages`

## Path parameters

- `scenario_run_id` string, required

## Headers

- `X-Messages-CSRF-Token` string, required

## Request body

- object

## Response `200`

Attachment staged

- VerifyMessagingUpload
  - `upload_id` string, required
  - `attachment` VerifyMessagingAttachment, required
    - `id` string, required
    - `name` string, required
    - `content_type` string, required
    - `byte_size` integer, required
    - `url` string, required
    - `download_url` string: Original file; url may be a JPEG preview for HEIC
    - `kind` 'image' | 'video' | 'audio' | 'file', required

## Other responses

- `201`: Attachment staged for this actor and conversation for one day
- `401`: Session required
- `403`: Origin, CSRF or permission refused
- `404`: Not found
- `422`: Invalid attachment or conversation unavailable
- `502`: Bad gateway

---

[API](https://skmtc.dev/composal/apis/vex-api.md) - [All operations](https://skmtc.dev/composal/apis/vex-api/llms.txt) - [OpenAPI document](https://skmtc.dev/composal/apis/vex-api/revisions/74298a24e040?raw)