> ## Documentation Index > Fetch the complete documentation index at: https://docs.varg.ai/llms.txt > Use this file to discover all available pages before exploring further. # Upload bytes to an upload session > Second step of the large-file flow started by `POST /files/upload-session`. Send the raw file bytes as the request body (not multipart) with the `Content-Type` from the session. Maximum size is 200 MB. A session accepts one upload and expires after 1 hour. This endpoint needs no API key: the unguessable `session_id` is the credential, and CORS allows any origin so browser widgets can call it. The file is registered in your account automatically; `registered` is `false` only if registration failed after the bytes were stored, in which case call `POST /files/import` with `public_url`. ## OpenAPI ````yaml /openapi.yaml put /files/upload/{session_id} openapi: 3.1.0 info: title: varg API version: 2.0.0 description: | Unified REST API for AI media generation at `api.varg.ai/v2`. One API key, ~80 models across 8 providers, async jobs, stable output URLs on `s3.varg.ai`, files with lineage, and transparent credit billing (1 credit = 1 cent = $0.01). **The async job pattern:** every generation request returns `202 Accepted` with a job object (`status: queued`). Poll `GET /jobs/{id}` until the job reaches a terminal status (`completed`, `failed`, or `cancelled`), then read `output.outputs[0].url`. Alternatively, set `options.webhook_url` in the request to receive an HMAC-signed callback when the job finishes. servers: - url: https://api.varg.ai/v2 security: - bearerAuth: [] tags: - name: Generation description: >- Create generation jobs (image, video, speech, music, transcription, ffmpeg, render, pipeline) - name: Tools description: Discover tools, their schemas, and call any tool generically - name: Jobs description: Poll and manage job lifecycle - name: Files description: Upload, import, probe, and manage files - name: Folders description: Group files into folders and file generated output automatically - name: Lineage description: Resolve which job produced a file - name: Presets description: Browse and apply reusable parameter values — voices, styles - name: Templates description: Browse, publish, use and render community templates - name: Pricing description: Estimate costs and browse the price catalog - name: Billing description: Balance, usage, and transaction history - name: Analytics description: >- Spend, runs and files over time — summaries, time series, breakdowns, activity - name: Account description: Identity and API key management paths: /files/upload/{session_id}: put: tags: - Files summary: Upload bytes to an upload session description: > Second step of the large-file flow started by `POST /files/upload-session`. Send the raw file bytes as the request body (not multipart) with the `Content-Type` from the session. Maximum size is 200 MB. A session accepts one upload and expires after 1 hour. This endpoint needs no API key: the unguessable `session_id` is the credential, and CORS allows any origin so browser widgets can call it. The file is registered in your account automatically; `registered` is `false` only if registration failed after the bytes were stored, in which case call `POST /files/import` with `public_url`. operationId: uploadFileToSession parameters: - name: session_id in: path required: true description: The `session_id` from `POST /files/upload-session` schema: type: string example: file_abc123 requestBody: required: true content: application/octet-stream: schema: type: string format: binary '*/*': schema: type: string format: binary responses: '200': description: Bytes stored content: application/json: schema: $ref: '#/components/schemas/UploadSessionResult' examples: stored: value: ok: true public_url: https://s3.varg.ai/files/acc_x/file_abc123.mp4 size: 48234112 media_type: video/mp4 file_id: file_abc123 registered: true '400': description: Empty body (`empty_body`) or missing session id (`missing_session`) content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '410': description: >- Session not found, expired, or already used (`session_expired`). Create a new session. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '413': description: File larger than 200 MB (`file_too_large`) content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '500': description: Storing the file failed (`upload_failed`) content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' security: [] components: schemas: UploadSessionResult: type: object required: - ok - public_url - size - media_type - registered properties: ok: type: boolean public_url: type: string size: type: integer description: Bytes stored media_type: type: string file_id: type: - string - 'null' description: Null when registration failed (`registered` is false) registered: type: boolean description: Whether the file was added to your Files ErrorResponse: type: object properties: error: type: object properties: code: type: string example: model_not_found message: type: string example: 'Unknown model: flux-shnell' details: {} securitySchemes: bearerAuth: type: http scheme: bearer description: | varg API key (`varg_...`). Get one at [app.varg.ai](https://app.varg.ai) or run `bunx vargai login`. App sessions may alternatively send a Supabase JWT. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.