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GuidesAPI ReferenceChangelogModel Versioning
GuidesAPI ReferenceChangelogModel Versioning
    • Getting Started
        • Generate Edit Schema
        • Edit File
      • Batch Processing
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On this page
  • Tutorial and explanation video
  • Quick Start
  • Conditional Form Editing
  • Endpoints
  • POST /edit_runs
  • GET /edit_runs/{id}
  • DELETE /edit_runs/{id}
  • Configuration Options
  • Instructions
  • Schema Generation Instructions
  • Schema
  • Schema Types
  • Schema Properties
  • Example Schema
  • Signature Image Fills
  • Combed Fields
  • Advanced Options
  • Status Values
  • Error Handling
  • Error Codes
  • Examples
  • Filling a Simple Form with Schema
  • Async Processing with Polling
  • Best Practices
Core Document ProcessingEditing

Edit File

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The Edit endpoint allows you to programmatically edit PDF documents by detecting form fields and filling them with provided data. This endpoint is ideal for:

  • Automatically filling out PDF forms
  • Pre-populating documents with customer data
  • Generating filled documents at scale

If you need Extend to detect the form fields and generate a starter schema first, use Generate Edit Schema.

Tutorial and explanation video

Quick Start

1import { ExtendClient } from "extend-ai";
2
3const client = new ExtendClient({ token: "YOUR_API_KEY" });
4
5// client.edit() is for testing, we recommend using webhooks or polling with client.editRuns.createAndPoll() in production
6const result = await client.edit({
7  file: {
8    url: "https://example.com/documents/form.pdf",
9  },
10  config: {
11    instructions: "Fill out the form with the provided data",
12    advancedOptions: {
13      flattenPdf: true
14    }
15  }
16});
17
18console.log("Document edited successfully:", result);
19// Download the filled PDF
20const downloadUrl = result.output?.editedFile?.presignedUrl;

Conditional Form Editing

Edit schemas support root-level JSON Schema conditionals, so you can make fields required or optional based on other form values. Supported keywords include dependentRequired, if / then / else, allOf, oneOf, anyOf, and not.

1{
2  "type": "object",
3  "properties": {
4    "employmentType": {
5      "enum": ["FULL_TIME", "CONTRACTOR"],
6      "extend_edit:field_type": "dropdown"
7    },
8    "contractEndDate": {
9      "type": ["string", "null"],
10      "extend_edit:field_type": "text"
11    }
12  },
13  "if": {
14    "properties": {
15      "employmentType": {
16        "enum": ["CONTRACTOR"]
17      }
18    }
19  },
20  "then": {
21    "required": ["contractEndDate"]
22  }
23}

This is useful for forms where follow-up fields only apply to a subset of users. If you do not already have a schema for the form, you can generate one with the Generate Edit Schema API and then refine the conditional logic.

Endpoints

POST /edit_runs

Create an edit run to edit a PDF document. All edit operations are asynchronous - the endpoint returns immediately with an edit run ID that can be used to poll for results.

Request Body

FieldTypeRequiredDescription
fileobjectYesFile to edit
file.namestringNoName of the file
file.urlstringYes*URL to download the file
file.idstringYes*Existing Extend file ID
configobjectYesConfiguration for the edit operation

*One of url or id must be provided.

Response

1{
2  "object": "edit_run",
3  "id": "edr_xK9mLPqRtN3vS8wF5hB2cQ",
4  "file": {
5    "object": "file",
6    "id": "file_Zk9mNP12Qw4yTv8BdR3H",
7    "name": "form.pdf",
8    "type": "PDF"
9  },
10  "status": "PROCESSING",
11  "failureReason": null,
12  "config": {
13    "instructions": "Fill out the form with the provided data"
14  },
15  "output": null,
16  "metrics": null,
17  "usage": null
18}

GET /edit_runs/{id}

Retrieve the status and results of an edit run. Poll this endpoint until status is PROCESSED or FAILED.

Path Parameters

ParameterTypeDescription
idstringThe edit run ID

Response (Processing)

1{
2  "object": "edit_run",
3  "id": "edr_xK9mLPqRtN3vS8wF5hB2cQ",
4  "file": { ... },
5  "status": "PROCESSING",
6  "failureReason": null,
7  "config": { ... },
8  "output": null,
9  "metrics": null,
10  "usage": null
11}

Response (Completed)

1{
2  "object": "edit_run",
3  "id": "edr_xK9mLPqRtN3vS8wF5hB2cQ",
4  "file": {
5    "object": "file",
6    "id": "file_Zk9mNP12Qw4yTv8BdR3H",
7    "name": "form.pdf",
8    "type": "PDF"
9  },
10  "status": "PROCESSED",
11  "failureReason": null,
12  "config": { ... },
13  "output": {
14    "editedFile": {
15      "id": "file_Ab3cDE45Fg6hIj7KlM8nO",
16      "presignedUrl": "https://extend-ai-files.s3.amazonaws.com/..."
17    },
18    "filledValues": { ... }
19  },
20  "metrics": { "processingTimeMs": 1234 },
21  "usage": { "credits": 1 }
22}

DELETE /edit_runs/{id}

Delete an edit run and all associated data. This operation is permanent and cannot be undone.

Path Parameters

ParameterTypeDescription
idstringThe edit run ID

Response

1{
2  "id": "edr_xK9mLPqRtN3vS8wF5hB2cQ"
3}

Configuration Options

The config object controls how documents are edited.

Instructions

instructions string

Natural language instructions for the edit operation. Use this to provide context or specific guidance on how to fill the form.

1{
2  "config": {
3    "instructions": "Fill out all fields on the form. For the signature field, use 'John Doe'. Leave optional fields blank if no data is provided."
4  }
5}

Schema Generation Instructions

schemaGenerationInstructions string

Additional instructions used when Extend needs to generate a schema from the PDF. This is useful when you want to bias field detection or naming without providing a full schema yourself.

1{
2  "config": {
3    "schemaGenerationInstructions": "Detect signature fields, preserve table structure, and use customer-friendly field names."
4  }
5}

Schema

schema object

A JSON Schema defining the structure of fields to edit. The schema uses extend_edit:* properties to specify PDF field types, bounding box positions, text styling options, values to fill, and optional signature image fills.

Schema Types

The type property supports the following formats:

Type FormatDescription
["string", "null"]Nullable string field (for text, signature)
["number", "null"]Nullable number field (for text)
["integer", "null"]Nullable integer field (for text)
["boolean", "null"]Nullable boolean field (for checkbox, radio)
"array"Array field (for tables)
"object"Object field (for signatures)
(no type, use enum)Enum field (for radio, optionList, dropdown)

Schema Properties

Each field in the schema can include:

PropertyTypeDescription
typestring or arrayJSON type (see table above)
descriptionstringDescription of the field
extend_edit:field_typestringPDF field type: "text", "checkbox", "radio", "dropdown", "optionList", "signature", "table"
extend_edit:bboxobjectBounding box with left, top, right, bottom (pixel coordinates)
extend_edit:bboxesarrayAn array of bounding boxes used for radio enums only. Enums are matched on index to a bounding box in this array.
extend_edit:page_indexintegerZero-based page index
extend_edit:valueanyThe value to fill into this field
extend_edit:imageobjectImage fill for signature fields. Use { "image_url": "https://..." } with a PNG or JPEG URL.
extend_edit:text_edit_optionsobjectText styling: combing, maxLength, fontSize, fontColor, font
extend_edit:column_widthnumberWidth of the column as a percentage (for table fields)
extend_edit:row_heightsarrayArray of row height percentages (for array/table fields)
itemsobjectSchema for array items (when type is “array”)
enumarrayAllowed values for enum/dropdown/radio fields
maxItemsintegerMaximum number of rows for array/table fields

Example Schema

1{
2  "config": {
3    "schema": {
4      "type": "object",
5      "required": ["policy_number", "policyholder_information_first_name"],
6      "properties": {
7        "policy_number": {
8          "type": ["string", "null"],
9          "description": "The policyholder's unique identification number.",
10          "extend_edit:bbox": {
11            "left": 0.250,
12            "top": 0.242,
13            "right": 0.454,
14            "bottom": 0.267
15          },
16          "extend_edit:field_type": "text",
17          "extend_edit:page_index": 0,
18          "extend_edit:value": "12345678",
19          "extend_edit:text_edit_options": {
20            "combing": true,
21            "maxLength": 8
22          }
23        },
24        "policyholder_information_first_name": {
25          "type": ["string", "null"],
26          "description": "The first name of the policyholder.",
27          "extend_edit:bbox": {
28            "left": 0.608,
29            "top": 0.313,
30            "right": 0.880,
31            "bottom": 0.338
32          },
33          "extend_edit:field_type": "text",
34          "extend_edit:page_index": 0,
35          "extend_edit:value": "John",
36          "extend_edit:text_edit_options": {
37            "combing": true,
38            "maxLength": 9
39          }
40        },
41        "is_permanent_address_change": {
42          "type": ["boolean", "null"],
43          "description": "Check this box if the address provided is a permanent change.",
44          "extend_edit:bbox": {
45            "left": 0.088,
46            "top": 0.480,
47            "right": 0.107,
48            "bottom": 0.494
49          },
50          "extend_edit:field_type": "checkbox",
51          "extend_edit:page_index": 0,
52          "extend_edit:value": true
53        },
54        "patient_information_sex_male": {
55          "type": ["boolean", "null"],
56          "description": "A checkbox to indicate if the patient's sex is Male.",
57          "extend_edit:bbox": {
58            "left": 0.137,
59            "top": 0.570,
60            "right": 0.156,
61            "bottom": 0.585
62          },
63          "extend_edit:field_type": "checkbox",
64          "extend_edit:page_index": 0,
65          "extend_edit:value": false
66        }
67      },
68      "additionalProperties": false
69    }
70  }
71}

Field values are specified directly on each field using extend_edit:value. This replaces the legacy input object approach.

Signature Image Fills

For signature fields, you can provide an image instead of a text value:

1{
2  "type": "object",
3  "extend_edit:field_type": "signature",
4  "extend_edit:image": {
5    "image_url": "https://example.com/signature.png"
6  }
7}

Combed Fields

For fields that require character-by-character input (like SSN, phone numbers, or policy numbers), use combing: true with a maxLength:

1{
2  "extend_edit:text_edit_options": {
3    "combing": true,
4    "maxLength": 9
5  }
6}

Advanced Options

advancedOptions.flattenPdf boolean

When enabled, flattens the PDF after editing, making form fields non-editable. This is useful for generating final documents. Default: false.

advancedOptions.tableParsingEnabled boolean

When enabled, parses table structures in the document. Default: false.

1{
2  "config": {
3    "advancedOptions": {
4      "flattenPdf": true,
5      "tableParsingEnabled": false
6    }
7  }
8}

advancedOptions.radioEnumsEnabled boolean

When enabled, imported radio fields are modeled as enums in the schema, ensuring only one of the radio widgets is filled.

advancedOptions.nativeFieldsOnly boolean

When enabled, only native AcroForm fields from the PDF are used in the schema.

Status Values

StatusDescription
PROCESSINGThe file is being edited
PROCESSEDThe edit completed successfully
FAILEDThe edit failed (see failureReason)

Error Handling

When an error occurs, the API returns a structured error response:

1{
2  "code": "FILE_TYPE_NOT_SUPPORTED",
3  "message": "Only PDF files are supported for editing",
4  "requestId": "req_abc123",
5  "retryable": false
6}

Error Codes

Error CodeDescriptionRetryable
INVALID_CONFIG_OPTIONSInvalid configuration options❌
UNABLE_TO_DOWNLOAD_FILECould not download the file from the URL❌
FILE_TYPE_NOT_SUPPORTEDFile type not supported (only PDFs)❌
FILE_SIZE_TOO_LARGEFile exceeds maximum size❌
CORRUPT_FILEFile is corrupt❌
OCR_ERROROCR processing error✅
PASSWORD_PROTECTED_FILEFile is password protected. Retry with the file’s password using file.settings.password. See Password-Protected Files.❌
FAILED_TO_CONVERT_TO_PDFPDF conversion failed❌
SCHEMA_VALIDATION_FAILEDSchema validation error❌
INTERNAL_ERRORInternal server error✅

Examples

Filling a Simple Form with Schema

1// /edit is for testing, we recommend using webhooks or polling with /edit_runs in production
2const response = await fetch("https://api.extend.ai/edit", {
3  method: "POST",
4  headers: {
5    Authorization: "Bearer <API_TOKEN>",
6    "Content-Type": "application/json",
7    "x-extend-api-version": "2026-02-09"
8  },
9  body: JSON.stringify({
10    file: {
11      url: "https://example.com/application-form.pdf"
12    },
13    config: {
14      schema: {
15        type: "object",
16        properties: {
17          applicant_name: {
18            type: ["string", "null"],
19            "extend_edit:field_type": "text",
20            "extend_edit:page_index": 0,
21            "extend_edit:bbox": { left: 0.1, top: 0.2, right: 0.4, bottom: 0.23 },
22            "extend_edit:value": "Jane Smith"
23          },
24          application_date: {
25            type: ["string", "null"],
26            "extend_edit:field_type": "text",
27            "extend_edit:page_index": 0,
28            "extend_edit:bbox": { left: 0.5, top: 0.2, right: 0.8, bottom: 0.23 },
29            "extend_edit:value": "2024-03-21"
30          },
31          email_address: {
32            type: ["string", "null"],
33            "extend_edit:field_type": "text",
34            "extend_edit:page_index": 0,
35            "extend_edit:bbox": { left: 0.1, top: 0.3, right: 0.4, bottom: 0.33 },
36            "extend_edit:value": "jane@example.com"
37          }
38        },
39        required: ["applicant_name"],
40        additionalProperties: false
41      },
42      advancedOptions: {
43        flattenPdf: true
44      }
45    }
46  }),
47});
48
49const data = await response.json();
50// Download the filled PDF
51const downloadUrl = data.output.editedFile.presignedUrl;

Async Processing with Polling

1// Start edit run
2const startResponse = await fetch("https://api.extend.ai/edit_runs", {
3  method: "POST",
4  headers: {
5    Authorization: "Bearer <API_TOKEN>",
6    "Content-Type": "application/json",
7    "x-extend-api-version": "2026-02-09"
8  },
9  body: JSON.stringify({
10    file: { url: "https://example.com/large-form.pdf" },
11    config: {
12      schema: {
13        type: "object",
14        properties: {
15          name: {
16            type: ["string", "null"],
17            "extend_edit:field_type": "text",
18            "extend_edit:page_index": 0,
19            "extend_edit:bbox": { left: 0.1, top: 0.1, right: 0.5, bottom: 0.13 },
20            "extend_edit:value": "John Doe"
21          }
22        },
23        additionalProperties: false
24      }
25    }
26  }),
27});
28
29const startData = await startResponse.json();
30const editRunId = startData.id;
31
32// Poll for completion
33let result;
34while (true) {
35  const statusResponse = await fetch(
36    `https://api.extend.ai/edit_runs/${editRunId}`,
37    {
38      headers: {
39        Authorization: "Bearer <API_TOKEN>",
40        "x-extend-api-version": "2026-02-09"
41      }
42    }
43  );
44  
45  const statusData = await statusResponse.json();
46  result = statusData;
47  
48  if (result.status === "PROCESSED" || result.status === "FAILED") {
49    break;
50  }
51  
52  // Wait before polling again
53  await new Promise(resolve => setTimeout(resolve, 1000));
54}
55
56if (result.status === "PROCESSED") {
57  console.log("Output file:", result.output.editedFile.presignedUrl);
58} else {
59  console.error("Edit failed:", result.failureReason);
60}

Best Practices

  1. Implement polling for all operations - All edit runs are async. Poll GET /edit_runs/{id} until status is PROCESSED or FAILED.

  2. Flatten for final documents - Enable flattenPdf: true when generating final documents to prevent further editing.

  3. Use extend_edit:value on each field - Specify values directly on each field in your schema using the extend_edit:value property.

  4. Use instructions for context - Provide clear instructions when field mapping isn’t straightforward.

  5. Handle errors gracefully - Implement retry logic for retryable errors like OCR_ERROR and INTERNAL_ERROR.

  6. Enable table parsing for forms with tables - Set tableParsingEnabled: true for forms with large regions of empty table cells you want filled.

  7. Use correct bounding box format - Bounding boxes use left, top, right, bottom coordinates (pixel values).