Uploads API

Overview

The Uploads API accepts base64-encoded file payloads from clients, stores them on the server, and returns a fetchable URL. The agent-chat bridge forwards the returned URL to the runtime as a file message part. Uploads are commonly used by the Allternit mobile composer to stage photos or documents before sending.

Base URL

https://api.allternit.com/v1/uploads

All endpoints require a valid Bearer token in the Authorization header. See Authentication for details.

Endpoints

Method	Path	Description
POST	`/uploads`	Upload a base64-encoded file.
GET	`/uploads/:id`	Download a stored upload.

Upload file

POST /api/v1/uploads

Request body:

{
  "name": "architecture.png",
  "mediaType": "image/png",
  "dataBase64": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8BQDwAEhQGAhKmMIQAAAABJRU5ErkJggg=="
}

Limits:

Maximum decoded payload: 20 MB.
Upload IDs are alphanumeric and extensionless; the sidecar stores the original filename and media type.

Response:

{
  "uploadId": "abc123upload",
  "url": "/api/v1/uploads/abc123upload"
}

Download upload

GET /api/v1/uploads/abc123upload

The response returns the stored bytes with the original Content-Type. If the sidecar is missing, application/octet-stream is used.

Error codes

Status	Code	Description
200	—	Success.
201	—	Upload created.
400	`invalid_base64`	`dataBase64` is not valid base64.
400	`empty_upload`	The decoded payload is empty.
400	`invalid_upload_id`	Upload ID is empty or contains non-alphanumeric characters.
401	`unauthorized`	Missing or invalid authentication.
404	`upload_not_found`	Upload does not exist.
413	`too_large`	Decoded payload exceeds 20 MB.
500	`storage_error`	Failed to write upload or sidecar to disk.

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Base URL

Endpoints

Upload file

Download upload

Error codes

​Overview

​Base URL

​Endpoints

​Upload file

​Download upload

​Error codes

​Related links

Overview

Base URL

Endpoints

Upload file

Download upload

Error codes

Related links