Generate PDFs from Word templates in Java

With DocuGenerate, you can create PDF and Word documents directly from your Java application. This guide shows how to call each API method from Java 11 or later. For the full list of parameters and responses, see the API Reference.

Summary

1. Authentication
2. Create template
3. List templates
4. Get template
5. Update template
6. Delete template
7. Generate document
8. List documents
9. Get document
10. Update document
11. Delete document

1. Authentication

Every request is authenticated by sending your API Key in the Authorization header. Store the key in an environment variable rather than hardcoding it in your source code:

export DOCUGENERATE_API_KEY="YOUR-API-KEY"

The examples use the HttpClient built into Java, and the Jackson library to read and write JSON. If you use Maven, add Jackson to your pom.xml:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.18.2</version>
</dependency>

Each example is written as the body of the main method of a class containing these imports and fields. Since HttpClient doesn’t throw an exception on HTTP error statuses, each example checks the status code before reading the response:

import com.fasterxml.jackson.databind.ObjectMapper;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.UUID;

public class DocuGenerateExample {

    static final String API_URL = "https://api.docugenerate.com/v1";
    static final String API_KEY = System.getenv("DOCUGENERATE_API_KEY");
    static final HttpClient client = HttpClient.newHttpClient();
    static final ObjectMapper mapper = new ObjectMapper();

    public static void main(String[] args) throws Exception {
        // Add the example code here
    }
}

If your account stores data in another region, replace the base URL with the matching regional endpoint, for example https://api.eu.docugenerate.com/v1.

2. Create template

To create a template, upload the template file with a POST /template request. This endpoint requires the multipart/form-data content type. Since HttpClient doesn’t build multipart bodies on its own, add this helper method to the class. It takes the form fields as name and value pairs, and sends a Path value as a file:

static HttpRequest.BodyPublisher multipart(String boundary, Object... fields) throws Exception {
    var parts = new ArrayList<byte[]>();
    for (int i = 0; i < fields.length; i += 2) {
        var header = "--" + boundary + "\r\nContent-Disposition: form-data; name=\"" + fields[i] + "\"";
        if (fields[i + 1] instanceof Path) {
            var path = (Path) fields[i + 1];
            header += "; filename=\"" + path.getFileName() + "\"\r\nContent-Type: application/octet-stream";
            parts.add((header + "\r\n\r\n").getBytes(StandardCharsets.UTF_8));
            parts.add(Files.readAllBytes(path));
        } else {
            parts.add((header + "\r\n\r\n" + fields[i + 1]).getBytes(StandardCharsets.UTF_8));
        }
        parts.add("\r\n".getBytes(StandardCharsets.UTF_8));
    }
    parts.add(("--" + boundary + "--\r\n").getBytes(StandardCharsets.UTF_8));
    return HttpRequest.BodyPublishers.ofByteArrays(parts);
}

Then send the template file with a random boundary, which must be the same in the body and in the Content-Type header:

var boundary = UUID.randomUUID().toString();

var request = HttpRequest.newBuilder(URI.create(API_URL + "/template"))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .header("Content-Type", "multipart/form-data; boundary=" + boundary)
    .POST(multipart(boundary,
        "file", Path.of("Business Letter.docx"),
        "name", "Business Letter"
    ))
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var template = mapper.readTree(response.body());
System.out.println(template.get("id").asText());

The response contains the new template, including the tags detected automatically in the file:

{
  "enhanced_syntax": false,
  "versioning_enabled": false,
  "folder": [],
  "tags": {
    "valid": [
      "Date",
      "Name",
      "Job Title",
      "Company Name",
      "Street Address",
      "City",
      "State",
      "Zip Code",
      "Email",
      "Phone"
    ],
    "invalid": []
  },
  "created": 1791055374301,
  "updated": 1791055374301,
  "name": "Business Letter",
  "delimiters": {
    "left": "[",
    "right": "]"
  },
  "filename": "Business Letter.docx",
  "format": ".docx",
  "region": "eu",
  "page_count": 1,
  "image_uri": "https://firebasestorage.googleapis.com/v0/b/storage.eu.docugenerate.com/o/templates%2FuVE30i1427KQsYcED0bl%2FBusiness%20Letter.png?alt=media&token=0ce64a4b-495a-426b-8783-42b479f7ae38",
  "preview_uri": "https://firebasestorage.googleapis.com/v0/b/storage.eu.docugenerate.com/o/templates%2FuVE30i1427KQsYcED0bl%2FBusiness%20Letter.pdf?alt=media&token=0b3939c7-824e-4979-9aca-ca4a87175cbf",
  "template_uri": "https://firebasestorage.googleapis.com/v0/b/storage.eu.docugenerate.com/o/templates%2FuVE30i1427KQsYcED0bl%2FBusiness%20Letter.docx?alt=media&token=d37a4458-3620-48db-94b8-6ac46f0442ab",
  "id": "uVE30i1427KQsYcED0bl"
}

Keep the template id, as you’ll need it to generate documents. The following optional parameters can also be added to the form:

delimiters: The delimiters used to detect the tags, sent as a JSON string, e.g. mapper.writeValueAsString(Map.of("left", "[", "right", "]")). By default, they’re determined automatically.
region: Where the template and its generated documents are stored, either us, eu, uk or au. By default, the account’s default region is used.
enhanced_syntax: Set to "true" to use nested properties and logical or mathematical operators in the tags.
versioning_enabled: Set to "true" to keep previous versions of the file when uploading a new one, if your plan allows it.
folder: The folder of the template, from root to leaf. Missing folders are created automatically.

To place the template in a folder, add one folder field for each level of the path. For example, to place it in the Letters > Business folder:

multipart(boundary,
    "file", Path.of("Business Letter.docx"),
    "name", "Business Letter",
    "folder", "Letters",
    "folder", "Business"
)

3. List templates

A GET /template request returns all the templates in your account:

var request = HttpRequest.newBuilder(URI.create(API_URL + "/template"))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .GET()
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var templates = mapper.readTree(response.body());
for (var template : templates) {
    System.out.println(template.get("id").asText() + " " + template.get("name").asText());
}

To only list the templates of a folder, repeat the folder query parameter for each level of the path. For example, to list the templates in the Letters > Business folder:

var request = HttpRequest.newBuilder(URI.create(API_URL + "/template?folder=Letters&folder=Business"))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .GET()
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

Only the templates placed directly in that folder are returned. Templates in its subfolders aren’t included. To learn more, see how to organize templates in folders with the API.

4. Get template

To retrieve a single template, call GET /template/{id} with its ID:

var templateId = "bet2oQirk0pSd9ctH9Qu";

var request = HttpRequest.newBuilder(URI.create(API_URL + "/template/" + templateId))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .GET()
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var template = mapper.readTree(response.body());
System.out.println(template.get("tags").get("valid"));

This is useful, for example, to check which merge tags the template expects before generating documents.

5. Update template

A PUT /template/{id} request updates a template. All the parameters are optional, so only send the ones you want to change. For example, to upload a new version of the file and rename the template:

var templateId = "bet2oQirk0pSd9ctH9Qu";
var boundary = UUID.randomUUID().toString();

var request = HttpRequest.newBuilder(URI.create(API_URL + "/template/" + templateId))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .header("Content-Type", "multipart/form-data; boundary=" + boundary)
    .PUT(multipart(boundary,
        "file", Path.of("Business Letter v2.docx"),
        "name", "Business Letter v2"
    ))
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var template = mapper.readTree(response.body());

As when creating a template, the body must be multipart/form-data, built with the multipart helper and the same boundary as in the Content-Type header. Besides file and name, the following optional parameters can be added to the form:

delimiters: The new delimiters, sent as a JSON string. If provided, the template is parsed again to detect the merge tags based on the new delimiters. When a new file is uploaded without delimiters, the current delimiters are used.
region: Moves the template to another region, either us, eu, uk or au. Documents generated afterwards are stored in the new region, while existing documents stay in their current region.
folder: Moves the template to another folder, with one folder field for each level of the path. Send "[]" to move the template out of any folder.
enhanced_syntax: Set to "true" or "false" to enable or disable the enhanced syntax.
versioning_enabled: Set to "true" or "false" to enable or disable the version history, if your plan allows it.

6. Delete template

To delete a template, send a DELETE /template/{id} request. The API responds with a 204 No Content status on success:

var templateId = "bet2oQirk0pSd9ctH9Qu";

var request = HttpRequest.newBuilder(URI.create(API_URL + "/template/" + templateId))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .DELETE()
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

7. Generate document

You generate documents with a POST /document request, passing the template_id and the data used to replace the merge tags:

var body = mapper.writeValueAsString(Map.of(
    "template_id", "bet2oQirk0pSd9ctH9Qu",
    "data", Map.of(
        "Date", "October 4, 2026",
        "Name", "Emily Carter",
        "Job Title", "Operations Manager",
        "Company Name", "Harbor Point Consulting",
        "Street Address", "118 West Street",
        "City", "Annapolis",
        "State", "Maryland",
        "Zip Code", "21405",
        "Email", "emily.carter@example.com",
        "Phone", "(410) 555-0142"
    ),
    "output_format", ".pdf"
));

var request = HttpRequest.newBuilder(URI.create(API_URL + "/document"))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .header("Content-Type", "application/json")
    .POST(HttpRequest.BodyPublishers.ofString(body))
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var document = mapper.readTree(response.body());
System.out.println(document.get("document_uri").asText());

The response contains the document’s properties:

{
  "created": 1791125416372,
  "template_id": "bet2oQirk0pSd9ctH9Qu",
  "name": "Business Letter",
  "format": ".pdf",
  "data_length": 1,
  "filename": "Business Letter.pdf",
  "document_uri": "https://firebasestorage.googleapis.com/v0/b/storage.us.docugenerate.com/o/documents%2FiESelthRt4uaYQRTemrL%2FBusiness%20Letter.pdf?alt=media&token=c4b259ec-249b-4b35-a62f-6a8dc0da75f3",
  "id": "iESelthRt4uaYQRTemrL"
}

The output_format can be .docx (the default), .pdf, .doc, .odt, .txt, .html, .png or a PDF/A version. You can also merge PDF files at the end of the generated document with merge_with, or add attachments with attach.

Downloading the file
The document_uri points to the generated file, which you can download and save to disk:

var download = HttpRequest.newBuilder(URI.create(document.get("document_uri").asText())).build();
var file = client.send(download, HttpResponse.BodyHandlers.ofByteArray());

if (file.statusCode() >= 400) {
    throw new RuntimeException("Download failed with status " + file.statusCode());
}

Files.write(Path.of(document.get("filename").asText()), file.body());

Receiving the file directly
If you don’t want the document stored in the cloud, set the Accept header to application/octet-stream. The API then responds with the binary file instead of JSON:

var body = mapper.writeValueAsString(Map.of(
    "template_id", "bet2oQirk0pSd9ctH9Qu",
    "data", Map.of(
        "Date", "October 4, 2026",
        "Name", "Emily Carter",
        "Job Title", "Operations Manager",
        "Company Name", "Harbor Point Consulting",
        "Street Address", "118 West Street",
        "City", "Annapolis",
        "State", "Maryland",
        "Zip Code", "21405",
        "Email", "emily.carter@example.com",
        "Phone", "(410) 555-0142"
    ),
    "output_format", ".pdf"
));

var request = HttpRequest.newBuilder(URI.create(API_URL + "/document"))
    .header("Authorization", API_KEY)
    .header("Accept", "application/octet-stream")
    .header("Content-Type", "application/json")
    .POST(HttpRequest.BodyPublishers.ofString(body))
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofByteArray());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + new String(response.body()));
}

Files.write(Path.of("Business Letter.pdf"), response.body());
System.out.println(response.headers().firstValue("X-Document-Id").orElse(""));

Batch document generation
To generate several documents in one request, pass a list of maps as data. A document is generated for each map:

var body = mapper.writeValueAsString(Map.of(
    "template_id", "bet2oQirk0pSd9ctH9Qu",
    "data", List.of(
        Map.of("Date", "October 4, 2026", "Name", "Emily Carter", "Job Title", "Operations Manager", "Company Name", "Harbor Point Consulting", "Street Address", "118 West Street", "City", "Annapolis", "State", "Maryland", "Zip Code", "21405", "Email", "emily.carter@example.com", "Phone", "(410) 555-0142"),
        Map.of("Date", "October 4, 2026", "Name", "Daniel Brooks", "Job Title", "Logistics Coordinator", "Company Name", "Northfield Logistics", "Street Address", "2400 South Lamar Boulevard", "City", "Austin", "State", "Texas", "Zip Code", "78704", "Email", "daniel.brooks@example.com", "Phone", "(512) 555-0187")
    ),
    "output_format", ".pdf",
    "single_file", true,
    "page_break", true
));

var request = HttpRequest.newBuilder(URI.create(API_URL + "/document"))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .header("Content-Type", "application/json")
    .POST(HttpRequest.BodyPublishers.ofString(body))
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var document = mapper.readTree(response.body());

By default, all the documents are combined in a single file, with a page break after each one. Set page_break to false to remove the page breaks.

When single_file is false, a file is generated per data object and all the files are grouped in a .zip archive. Use the name parameter to name the archive, and output_name with merge tags to give each file a dynamic name, such as Letter for [Name]:

var body = mapper.writeValueAsString(Map.of(
    "template_id", "bet2oQirk0pSd9ctH9Qu",
    "data", List.of(...),
    "output_format", ".pdf",
    "single_file", false,
    "name", "Business Letters",
    "output_name", "Letter for [Name]"
));

This generates a Business Letters.zip archive containing Letter for Emily Carter.pdf and Letter for Daniel Brooks.pdf. The merge tags in output_name must use the same delimiters as the template.

Using a data file
To generate documents in bulk from an Excel or CSV file, send the file in a multipart/form-data request. A document is generated for each row of the spreadsheet. If the file has several sheets, specify the sheet parameter to choose which one to use.

var boundary = UUID.randomUUID().toString();

var request = HttpRequest.newBuilder(URI.create(API_URL + "/document"))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .header("Content-Type", "multipart/form-data; boundary=" + boundary)
    .POST(multipart(boundary,
        "template_id", "bet2oQirk0pSd9ctH9Qu",
        "file", Path.of("Data.xlsx"),
        "output_format", ".pdf"
    ))
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

Using a data file is another form of batch generation, so the same parameters apply for combining generated documents in a single file or grouping them in a .zip archive with a custom name for each file.

8. List documents

A GET /document request returns the documents generated from a template, whose ID is passed in the template_id query parameter:

var request = HttpRequest.newBuilder(URI.create(API_URL + "/document?template_id=bet2oQirk0pSd9ctH9Qu"))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .GET()
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var documents = mapper.readTree(response.body());
for (var document : documents) {
    System.out.println(document.get("id").asText() + " " + document.get("name").asText() + " " + document.get("document_uri").asText());
}

9. Get document

To retrieve a single document, call GET /document/{id} with its ID:

var documentId = "iESelthRt4uaYQRTemrL";

var request = HttpRequest.newBuilder(URI.create(API_URL + "/document/" + documentId))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .GET()
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var document = mapper.readTree(response.body());

10. Update document

A PUT /document/{id} request renames a document, which is the only property that can be updated:

var documentId = "iESelthRt4uaYQRTemrL";
var body = mapper.writeValueAsString(Map.of("name", "Letter for Emily Carter"));

var request = HttpRequest.newBuilder(URI.create(API_URL + "/document/" + documentId))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .header("Content-Type", "application/json")
    .PUT(HttpRequest.BodyPublishers.ofString(body))
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

var document = mapper.readTree(response.body());

11. Delete document

To delete a document, send a DELETE /document/{id} request. The API responds with a 204 No Content status on success:

var documentId = "iESelthRt4uaYQRTemrL";

var request = HttpRequest.newBuilder(URI.create(API_URL + "/document/" + documentId))
    .header("Authorization", API_KEY)
    .header("Accept", "application/json")
    .DELETE()
    .build();

var response = client.send(request, HttpResponse.BodyHandlers.ofString());

if (response.statusCode() >= 400) {
    throw new RuntimeException("DocuGenerate API error " + response.statusCode() + ": " + response.body());
}

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