> ## Documentation Index > Fetch the complete documentation index at: https://docs.chariot.in/llms.txt > Use this file to discover all available pages before exploring further. # Create a batch > Submit one or more recordings for durable asynchronous transcription. > [!NOTE] > > Attach **one file** per request, or submit up to **100 URL inputs**. You can mix one upload with up to 99 URLs. Default limits are **3 hours** and **1 GiB per recording**, with a **512 KiB manifest**. See [Batch limits](https://docs.chariot.in/guides/speech-to-text/async-transcription.md#batch-limits) for request limits and per-file failure behavior. ## OpenAPI ````yaml api-reference/openapi.json POST /v1/asr/batches openapi: 3.1.0 info: title: Chariot API version: '1' description: >- Chariot is a voice AI platform built for Indian and English languages. Convert text into natural-sounding speech over a simple REST call, an HTTP audio stream, or a low-latency WebSocket, and transcribe speech to text over a streaming WebSocket or from a prerecorded file (Beta). This reference documents the public, API-key-authenticated endpoints. contact: name: Chariot Support email: support@chariot.in url: https://chariot.in servers: - url: https://api.chariot.in description: Production security: - APIKeyHeader: [] tags: - name: Text to Speech description: Convert text into speech synchronously or as a stream. - name: Speech to Text description: >- Transcribe prerecorded files (Beta) and review streaming speech-to-text sessions. - name: Voices description: Browse the voice catalog. - name: Account description: Inspect your credit balance and usage. paths: /v1/asr/batches: post: tags: - Speech to Text summary: Create a batch description: >- **Beta.** Submit up to 100 independent recordings using audio_url inputs, or attach one file with file_index: 0 and optionally add up to 99 URL inputs. Default limits: 3 hours and 1 GiB per recording, 2 GiB per multipart request, and 512 KiB per manifest. Audio URLs may contain up to 4,096 characters and are downloaded by the async worker after acceptance, with a 5-minute download timeout per attempt. Invalid manifests reject the whole submission; processing failures after acceptance affect only the individual transcription. See the [Async transcription guide](/guides/speech-to-text/async-transcription#batch-limits) for details. Returns 202 after acceptance, before transcription completes. Save the items mapping of custom_id to transcription id and poll for results. Matching idempotent retries preserve those IDs. CSV manifests are not supported. operationId: createASRBatch parameters: - name: Idempotency-Key in: header required: false schema: type: string maxLength: 128 description: >- Reuse the same key and identical manifest and file bytes to recover the original batch after a submission timeout. A changed request with the same key returns 409. requestBody: required: true content: application/json: schema: additionalProperties: false properties: inputs: items: additionalProperties: false properties: custom_id: maxLength: 128 minLength: 1 title: Custom Id type: string audio_url: anyOf: - maxLength: 4096 type: string - type: 'null' default: null title: Audio Url file_index: anyOf: - maximum: 0 minimum: 0 type: integer - type: 'null' default: null description: >- Use 0 to reference the single uploaded file. Omit for audio_url inputs. title: File Index language: description: >- Requested transcription languages supported by ASR; not output translation. enum: - en - hi - none - bn - gu - kn - ml - mr - or - pa - sa - ta - te title: ASRLanguage type: string default: none model_type: description: >- Public streaming ASR ``model_type`` values, the same parameter name TTS uses. A product name, never the checkpoint or serving name behind it: the upstream's served name is configuration and is never sent to a caller. enum: - chariot-1-asr-realtime title: ASRModelType type: string default: chariot-1-asr-realtime mode: description: >- File transcription always uses the high accuracy deployment. enum: - high_accuracy title: ASRFileMode type: string default: high_accuracy style: description: >- How code-mixed speech is written out. ``codemix`` writes borrowed words (usually English) in their own script, "मेरी meeting cancel हो गई", and is what the current deployment produces. ``native`` writes everything in the spoken language's script, "मेरी मीटिंग कैंसल हो गई". Only a deployment that advertises ``native`` can honour it. enum: - codemix - native title: ASRStyle type: string default: codemix include_timestamps: default: false title: Include Timestamps type: boolean required: - custom_id title: BatchInput type: object maxItems: 100 minItems: 1 title: Inputs type: array webhook_url: anyOf: - maxLength: 2048 type: string - type: 'null' default: null title: Webhook Url webhook_events: items: enum: - transcription.completed - transcription.failed - transcription.cancelled - batch.completed - batch.partially_completed - batch.failed - batch.cancelled type: string title: Webhook Events type: array required: - inputs title: BatchSubmission type: object multipart/form-data: schema: type: object required: - manifest properties: manifest: type: string description: >- JSON BatchSubmission with up to 100 inputs. Use file_index: 0 for the single optional uploaded file; use audio_url for other inputs. Manifest limit: 512 KiB. files: type: array maxItems: 1 description: >- At most one uploaded file per request, referenced exactly once by file_index: 0. Optional for URL-only submissions. Default limits: 1 GiB and 3 hours per recording; 2 GiB for the complete multipart request. items: type: string format: binary responses: '202': description: Accepted. content: application/json: schema: $ref: '#/components/schemas/ASRAsyncBatchAccepted' example: id: 1f4b3eed-2fdf-4495-b988-2b7145127058 status: queued created_at: '2026-10-27T08:41:44Z' started_at: null finished_at: null cancel_requested_at: null counts: total: 1 queued: 1 items_url: /v1/asr/history?batch_id=1f4b3eed-2fdf-4495-b988-2b7145127058 items: - id: 9cb6f4c5-b2bf-4d75-96e3-716f6f87d994 custom_id: meeting-1 webhook_signing_secret: null '401': $ref: '#/components/responses/Unauthorized' '403': description: ASR is not available for this workspace. content: application/json: schema: $ref: '#/components/schemas/Error' '409': description: Idempotency key was reused with a different request. content: application/json: schema: $ref: '#/components/schemas/Error' '413': description: >- Too many attached files (at most one), or upload/manifest exceeds its byte-size limit. content: application/json: schema: $ref: '#/components/schemas/Error' '415': description: Use application/json or multipart/form-data. content: application/json: schema: $ref: '#/components/schemas/Error' '422': description: Invalid parameters or input. content: application/json: schema: $ref: '#/components/schemas/Error' '429': description: Too many pending asynchronous transcriptions. Retry with backoff. content: application/json: schema: $ref: '#/components/schemas/Error' '503': description: >- Asynchronous transcription, a requested mode or webhook delivery is unavailable. content: application/json: schema: $ref: '#/components/schemas/Error' security: - APIKeyHeader: [] components: schemas: ASRAsyncBatchAccepted: properties: id: format: uuid title: Id type: string status: enum: - queued - processing - cancelling - completed - partially_completed - failed - cancelled title: Status type: string created_at: format: date-time title: Created At type: string started_at: anyOf: - type: string format: date-time - type: 'null' title: Started At finished_at: anyOf: - type: string format: date-time - type: 'null' title: Finished At cancel_requested_at: anyOf: - type: string format: date-time - type: 'null' title: Cancel Requested At counts: additionalProperties: type: integer title: Counts type: object items_url: title: Items Url type: string items: description: >- Input-to-transcription ID mapping in submission order. Preserved on matching idempotent retries. items: $ref: '#/components/schemas/ASRAsyncBatchItemReference' title: Items type: array webhook_signing_secret: anyOf: - type: string - type: 'null' default: null title: Webhook Signing Secret required: - id - status - created_at - started_at - finished_at - cancel_requested_at - counts - items_url - items title: BatchAccepted type: object Error: type: object description: Standard error envelope returned by all endpoints. properties: statusCode: type: integer description: HTTP status code, echoed in the body. error: type: string description: Machine-readable error class name. message: type: string description: Human-readable description of what went wrong. required: - statusCode - error - message ASRAsyncBatchItemReference: properties: id: description: >- Transcription ID for polling and cancellation; matches webhook transcription_id. format: uuid title: Id type: string custom_id: description: Customer-supplied identifier, unique within this batch. title: Custom Id type: string required: - id - custom_id title: BatchItemReference type: object responses: Unauthorized: description: Authentication failed. The API key is missing, invalid, or expired. content: application/json: schema: $ref: '#/components/schemas/Error' examples: missing: summary: No credentials provided value: statusCode: 401 error: UnauthorizedException message: No API key or user credentials provided invalid: summary: Invalid or unknown API key value: statusCode: 401 error: UnauthorizedException message: Invalid API Key or user credentials securitySchemes: APIKeyHeader: type: apiKey in: header name: chariotai-api-key description: >- Your Chariot API key, generated from the dashboard. Send it in the `chariotai-api-key` header on every request. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.