> ## Documentation Index > Fetch the complete documentation index at: https://developers.gonitro.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Forms > Extract Form Fields from PDF document The **Extract Forms** method of the Extractions endpoint allows you to retrieve form field values from a PDF document. This endpoint requires no additional parameters and automatically identifies all form fields present in the file. The endpoint returns a JSON object containing an array of form field objects, each containing the following fields: * `name`: The name assigned to the form field. * `value`: The extracted value, as a string. For checkboxes and radio buttons, this is typically the field's export value when selected (e.g., "Yes", "On", or the field's name). * `confidence`: The confidence score, ranging from 0.0 (lowest certainty) to 1.0 (highest certainty), for the extracted form field value. ### Output File Format The endpoint can return output either as JSON or as a binary file. The format depends on the `Accept` header (details below), which defaults to application/json. ### Processing When requesting JSON, you can run the operation synchronously or asynchronously. This is determined by the `Prefer` header (details below). * In sync mode, the response includes a URL pointing to the processed file. * In async mode, the request creates a Job, and the response contains the Job ID and status so you can track progress. Binary (octet-stream) responses are only available for synchronous operations. ### Custom File Delivery The endpoint supports custom file-delivery destinations through the optional delivery parameter. You can provide an upload target, such as your own PUT endpoint or a pre-signed S3 URL, and Nitro will upload the resulting file there. This works for both synchronous and asynchronous processing. * ### Sync delivery In synchronous calls, the [delivery](#body-delivery) parameter lets you direct Nitro to upload the output file to a custom URL endpoint or a pre-signed URL (e.g S3), by providing an upload url in the `uploadResultTo` or `uploadResultsTo` properties. #### Custom endpoint If implementing the upload endpoint by yourself, make sure your code or middleware configuration accepts requests without content-type headers. #### S3 delivery If you are using S3 to manage delivery uploads, follow this [AWS documentation](https://docs.aws.amazon.com/AmazonS3/latest/userguide/PresignedUrlUploadObject.html) to generate a pre-signed PUT URL. If using the AWS provided Python script, omit the `Content-Type` in Params to get the pre-signed url. For example: ```python theme={null} url = generate_presigned_url( s3_client, "put_object", { "Bucket": args.bucket, "Key": args.key, # Content-Type: "application/octet-stream" => Omit! }, 1000) ``` * ### Async delivery In asynchronous flows, you can also provide a custom URL or pre-signed S3 object via `uploadResultTo` or `uploadResultsTo`, to upload your file(s) once the Job is done processing. #### Callback For asynchronous processing, you can also include a [callback](#body-delivery-callback) URL within the delivery parameter. This callback is a POST endpoint that Nitro will call once the Job is created and running, providing details about the file-processing job. Example of Nitro’s callback request body: ```json theme={null} { "jobID": "babe2aa7-9b5d-4eb2-a679-5fc12cf0a490", "location": "https://api.gonitro.dev/jobs/babe2aa7-9b5d-4eb2-a679-5fc12cf0a490" } ``` #### Response behavior Matrix This matrix shows the expected response behavior based on content type, sync/async mode, and custom file-delivery settings. | | **JSON (`application/json`)** | **Binary (`application/octet-stream`)** | | ---------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------- | | **Synchronous** | Returns a JSON object with a file(s) URL(s). | Returns the processed file directly as binary. | | **Asynchronous (`respond-async`)** | Returns a JSON object with a Job ID and status. | Async preference ignored, returns sync binary. | | **Synchronous delivery** | File delivered to custom endpoint / Bucket, returns success confirmation. | N/A | | **Asynchronous delivery** | Returns a JSON object with a Job ID and status. The file(s) will be uploaded to the provided PUT endpoint / S3 Bucket at the end of process. If `callback` url is provided, Nitro will notify the endpoint with a JOB ID and location. | N/A | #### Limits The Platform API has the following limits: * File size: Maximum of 25 MB per request. This applies to single-file and multi-file requests. * Page count: Maximum of 250 pages per individual document. This applies to single-file and multi-file requests. Multiple documents may exceed 250 pages in total. * Retention time: Inputs and outputs are deleted approximately 15 minutes after the operation completes. ### Request ## OpenAPI ````yaml forms POST /extractions openapi: 3.0.3 info: title: Nitro API - Document Intelligence Platform description: >- Consolidated API for document intelligence operations including conversions, extractions, transformations, and job management. **Supported Operations:** - **Conversions**: PDF ↔ MS Office, Images ↔ PDF, Various formats to PDF - **Extractions**: Text extraction, PII detection, Bounding box extraction, PDF properties - **Transformations**: Rotate, Split, Merge, Flatten, Compress, Password protection, Redaction - **Jobs**: Asynchronous processing with status monitoring and result retrieval **Global Limits:** - Maximum file size: 25MB - Maximum number of pages: 200 version: 1.0.0 contact: name: Nitro API Support url: https://help.gonitro.com/support servers: - url: https://api.gonitro.dev description: API server security: [] tags: - name: Conversions description: >- Document format conversion operations including PDF to/from MS Office, images, and various other formats - name: Extractions description: >- Data extraction operations for text, metadata, PII detection, and bounding box information - name: Transformations description: >- PDF transformation operations including rotation, splitting, merging, compression, protection, and redaction - name: Jobs description: >- Asynchronous job management for monitoring, retrieving results, and canceling long-running operations paths: /extractions: post: tags: - Extractions summary: Extract Form Fields from PDF description: Extract Form Fields from PDF document parameters: - name: Accept in: header schema: $ref: '#/components/schemas/AcceptHeader' - name: Prefer in: header schema: $ref: '#/components/schemas/PreferHeader' requestBody: required: true content: multipart/form-data: schema: type: object properties: method: type: string description: 'The Extractions'' endpoint method: `extract-forms`' default: extract-forms enum: - extract-forms file: $ref: '#/components/schemas/FileUpload' delivery: $ref: '#/components/schemas/DeliverySingleFileOut' required: - method - file responses: '200': description: >- Returns either JSON or binary output depending on the Accept header (defaults to JSON). JSON responses include a file URL for synchronous tasks or a job status for asynchronous tasks. content: application/json: schema: oneOf: - $ref: '#/components/schemas/ExtractFormsResponse' - $ref: '#/components/schemas/AsyncJobResponse' application/octet-stream: schema: type: string format: binary '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '404': $ref: '#/components/responses/NotFound' '413': $ref: '#/components/responses/ContentTooLarge' '422': $ref: '#/components/responses/UnprocessableEntity' '500': $ref: '#/components/responses/InternalServerError' security: - BearerAuth: [] components: schemas: AcceptHeader: type: string enum: - application/json - application/octet-stream - '*/*' default: '*/*' description: >- Controls response format and behavior. See endpoint description above for detailed response combinations. - `application/json`: Returns JSON response with operation result - `application/octet-stream`: Returns binary file content - `*/*`: Defaults to JSON response PreferHeader: type: string enum: - respond-async description: >- Controls synchronous vs asynchronous operation. See endpoint description above for behavior details. - `respond-async`: Makes request asynchronous, returns job status for polling - No value: Synchronous response FileUpload: description: >+ The file to process. It can be provided as a binary upload or as a JSON remote file reference. oneOf: - type: string format: binary description: |- #### Binary file Standard multipart file binary upload field - type: object title: Remote file properties: URL: type: string format: uri description: URL of the remote file to process contentType: type: string description: The MIME type of the remote file example: application/pdf required: - URL - contentType description: |- #### Remote file JSON objects containing file URL and content type, sent with specific multipart encoding: `type` and `filename`. The playground **doesn't support** them. Plase test with an alternative tool (Ex: Postman). Example cURL file field for remote file: ```bash --form 'file={ "URL":"https://your-file.pdf", "contentType":"application/pdf" } ;type=application/vnd.gonitro.url+json ;filename=https://your-file.pdf' ``` DeliverySingleFileOut: type: object properties: uploadResultTo: $ref: '#/components/schemas/HTTPCall' callback: $ref: '#/components/schemas/Callback' description: >- This endpoint lets you supply your own URL to receive the single-file output. The URL may point to a custom API endpoint or a pre-signed S3 URL. The HTTP method defaults to PUT, but you can change it based on your implementation needs via the `verb` parameter. You can also provide custom headers, such as authentication headers or any others required by your endpoint. ExtractFormsResponse: type: object title: Sync - Forms properties: result: $ref: '#/components/schemas/FormResultType' required: - result AsyncJobResponse: type: object title: Async - Job properties: jobID: type: string example: 01234567-89ab-cdef-0123-456789abcdef status: type: string enum: - running progress: type: number description: Progress of the job as a float between 0.0 and 1.0 format: float default: 0 example: 0 HTTPCall: type: object properties: URL: type: string description: Your delivery endpoint URL nullable: false format: uri verb: type: string description: The HTTP method default: PUT enum: - GET - POST - PUT - DELETE - PATCH headers: type: array nullable: true description: Headers your file delivery endpoint might need (Optional) items: $ref: '#/components/schemas/Header' required: - URL - verb Callback: type: object description: >- POST endpoint that will get JOB ID and location when processing starts only on async processesing (see example above) properties: URL: type: string description: Your POST endpoint callback URL. nullable: false format: uri headers: type: array description: Headers your callback endpoint might need items: $ref: '#/components/schemas/Header' required: - URL FormResultType: type: object title: Form Fields properties: fields: type: array items: $ref: '#/components/schemas/FormField' description: Array of extracted form fields from the document averageConfidence: type: number format: float minimum: 0 maximum: 100 example: 96.5 description: Average confidence score for all form fields required: - fields - averageConfidence BadRequestProblemDetail: type: object description: Bad Request error details example: type: https://developers.gonitro.com/docs/build-nitro/errors#400-bad-request title: Bad Request status: 400 detail: Request validation failed instance: /platform/transformations allOf: - $ref: '#/components/schemas/ErrorResponse' UnauthorizedProblemDetail: type: object description: Unauthorized error details example: type: >- https://developers.gonitro.com/docs/build-nitro/errors#401-unauthorized title: Unauthorized status: 401 detail: Missing or invalid Authorization header instance: /platform/transformations allOf: - $ref: '#/components/schemas/ErrorResponse' NotFoundProblemDetail: type: object description: Not Found error details example: type: https://developers.gonitro.com/docs/build-nitro/errors#404-not-found title: Not Found status: 404 detail: Resource not found instance: /platform/transformations allOf: - $ref: '#/components/schemas/ErrorResponse' ContentTooLargeProblemDetail: type: object description: Content too large error details example: type: >- https://developers.gonitro.com/docs/build-nitro/errors#413-content-too-large title: Content too large status: 413 detail: Uploaded document exceeds the file size limit instance: /platform/transformations allOf: - $ref: '#/components/schemas/ErrorResponse' UnprocessableEntityProblemDetail: type: object description: Unprocessable Entity error details example: type: >- https://developers.gonitro.com/docs/build-nitro/errors#422-unprocessable-entity title: Unprocessable Entity status: 422 detail: The request was well-formed but could not be processed instance: /platform/transformations allOf: - $ref: '#/components/schemas/ErrorResponse' InternalServerErrorProblemDetail: type: object description: Internal Server Error details example: type: >- https://developers.gonitro.com/docs/build-nitro/errors#500-internal-server-error title: Internal Server Error status: 500 detail: An unexpected error occurred instance: /platform/transformations allOf: - $ref: '#/components/schemas/ErrorResponse' Header: type: object properties: name: type: string value: type: string required: - name - value FormField: type: object properties: name: type: string description: The name of the form field. value: type: string description: The extracted value of the form field. confidence: type: number format: float minimum: 0 maximum: 100 example: 97.65 description: Confidence score for the form field extraction. required: - name - value - confidence ErrorResponse: type: object properties: type: type: string description: A URI reference that identifies the problem type title: type: string description: A short, human-readable summary of the problem type status: type: integer format: int32 description: The HTTP status code detail: type: string description: A human-readable explanation specific to this occurrence instance: type: string description: A URI reference that identifies the specific occurrence responses: BadRequest: description: Bad Request - Invalid request parameters content: application/problem+json: schema: $ref: '#/components/schemas/BadRequestProblemDetail' Unauthorized: description: Unauthorized - Invalid or missing Authorization header content: application/problem+json: schema: $ref: '#/components/schemas/UnauthorizedProblemDetail' NotFound: description: Not Found - Resource not found content: application/problem+json: schema: $ref: '#/components/schemas/NotFoundProblemDetail' ContentTooLarge: description: Content Too Large - File size exceeds limit content: application/problem+json: schema: $ref: '#/components/schemas/ContentTooLargeProblemDetail' UnprocessableEntity: description: Unprocessable Entity - Request cannot be processed content: application/problem+json: schema: $ref: '#/components/schemas/UnprocessableEntityProblemDetail' InternalServerError: description: Internal Server Error - An unexpected error occurred content: application/problem+json: schema: $ref: '#/components/schemas/InternalServerErrorProblemDetail' securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: JWT ````