> ## Documentation Index
> Fetch the complete documentation index at: https://docs.helloatlas.in/llms.txt
> Use this file to discover all available pages before exploring further.

# POST /flow/init — Initialize Verification Flow

> Create a new document verification flow for a loan application. Returns a flow_uuid required in all subsequent multiupload, status, and extracts calls.

Every document verification session begins here. Call this endpoint once per application to create a flow, then use the returned `flow_uuid` in all subsequent `/multiupload`, `/status`, and `/extracts` calls.

## Endpoint

```
POST /verification/flow/init
```

## Request headers

<ParamField header="Token" type="string" required>
  JWT access token obtained from [POST /authtoken](/api-reference/auth/generate-token).
</ParamField>

## Request body

<ParamField body="product_type" type="string" required>
  The product type that governs which document set and cross-checks apply to this flow.
</ParamField>

<ParamField body="application_id" type="string" required>
  Your internal identifier for the loan application or case. Atlas echoes this value back in callback payloads.
</ParamField>

<ParamField body="auth_url" type="string" required>
  A URI that Atlas calls to authenticate its callbacks to your system before delivering results. Must be reachable from Atlas servers.
</ParamField>

<ParamField body="callback_url" type="string" required>
  A URI where Atlas POSTs the extracted OCR data and cross-check results when processing is complete. Must accept `POST` requests with a JSON body.
</ParamField>

<ParamField body="flow_params" type="object">
  An optional object for additional flow configuration. Pass an empty object `{}` if you have no extra parameters.
</ParamField>

## Response

<ResponseField name="flow_uuid" type="string">
  A UUID that uniquely identifies this verification flow. Save this value — you will pass it to every subsequent API call in this session.
</ResponseField>

## Example

<CodeGroup>
  ```bash cURL theme={null}
  curl --request POST \
    --url https://api.helloatlas.in/v3/verification/flow/init \
    --header "Token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..." \
    --header "Content-Type: application/json" \
    --data '{
      "product_type": "POC_CDL",
      "application_id": "12321321",
      "auth_url": "https://your-system.example.com/atlas/auth",
      "callback_url": "https://your-system.example.com/atlas/callback",
      "flow_params": {}
    }'
  ```

  ```json 201 Created theme={null}
  {
    "flow_uuid": "ec57821d-d766-4e24-81ef-a2768094511b"
  }
  ```
</CodeGroup>

## Error responses

| Status | Meaning                                                                                                   |
| ------ | --------------------------------------------------------------------------------------------------------- |
| `400`  | `Missing or empty required parameters: ['application_id']` — one or more required body fields are absent. |
| `401`  | `Invalid token` — the `Token` header is missing, expired, or invalid.                                     |

<Note>
  Atlas will POST the final extraction results to your `callback_url` when processing completes. Ensure that URL is publicly accessible and returns an HTTP `2xx` response. You can also poll [GET /status](/api-reference/verification/status) and fetch results manually via [GET /extracts](/api-reference/verification/extracts).
</Note>