DOCX templating API for Word-based document generation

Populate Word DOCX templates with JSON data and generate polished documents for automated workflows.

Keep template authoring in Word

Let operations, legal, and business teams maintain DOCX templates in Word while your application injects runtime data through a simple HTTP API.

Fill text, loops, nested data, and images

Generate personalized documents from JSON model data, including repeated sections and richer placeholders for real document-generation workflows.

Built for automated document pipelines

Use REST, Postman, JavaScript, Python, Java, C#, PHP, or HTTP to create proposals, agreements, and internal documents without self-hosting a document templating system.

Try it out

This example fills a DOCX template with JSON data and returns a generated DOCX document.

Try it out in three steps

Create a Word template named template.docx and add placeholders like Hello {name}, Company: {company}, and Date: {date}.
Run the code from the same folder.
Open result.docx to verify the placeholders were replaced.

Advanced API

curl -X POST https://api.nutrient.io/process_office_template \
  -H "Authorization: Bearer your_api_key_here" \
  -o result.docx \
  --fail \
  -F 'document=@template.docx;type=application/vnd.openxmlformats-officedocument.wordprocessingml.document' \
  -F 'model={"name":"Alex","company":"Acme","date":"2026-04-10"}'

curl -X POST https://api.nutrient.io/process_office_template ^
  -H "Authorization: Bearer your_api_key_here" ^
  -o result.docx ^
  --fail ^
  -F "document=@template.docx;type=application/vnd.openxmlformats-officedocument.wordprocessingml.document" ^
  -F "model={\"name\":\"Alex\",\"company\":\"Acme\",\"date\":\"2026-04-10\"}"

package com.example.pspdfkit;

import java.io.File;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;

import org.json.JSONObject;

import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public final class PspdfkitApiExample {
  public static void main(final String[] args) throws IOException {
    final MediaType mediaType = MediaType.parse("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
    final RequestBody body = new MultipartBody.Builder()
      .setType(MultipartBody.FORM)
      .addFormDataPart(
        "document",
        "template.docx",
        RequestBody.create(
          mediaType,
          new File("template.docx")
        )
      )
      .addFormDataPart(
        "model",
        new JSONObject()
          .put("name", "Alex")
          .put("company", "Acme")
          .put("date", "2026-04-10").toString()
      )
      .build();

    final Request request = new Request.Builder()
      .url("https://api.nutrient.io/process_office_template")
      .method("POST", body)
      .addHeader("Authorization", "Bearer your_api_key_here")
      .build();

    final OkHttpClient client = new OkHttpClient()
      .newBuilder()
      .build();

    final Response response = client.newCall(request).execute();

    if (response.isSuccessful()) {
      Files.copy(
        response.body().byteStream(),
        FileSystems.getDefault().getPath("result.docx"),
        StandardCopyOption.REPLACE_EXISTING
      );
    } else {
      throw new IOException(response.body().string());
    }
  }
}

using System;
using System.IO;
using System.Net;
using RestSharp;

namespace PspdfkitApiDemo
{
  class Program
  {
    static void Main(string[] args)
    {
      var client = new RestClient("https://api.nutrient.io/process_office_template");

      var request = new RestRequest(Method.POST)
        .AddHeader("Authorization", "Bearer your_api_key_here")
        .AddFile("document", "template.docx")
        .AddParameter("model", new JsonObject
        {
          ["name"] = "Alex",
          ["company"] = "Acme",
          ["date"] = "2026-04-10"
        }.ToString());

      request.AdvancedResponseWriter = (responseStream, response) =>
      {
        if (response.StatusCode == HttpStatusCode.OK)
        {
          using (responseStream)
          {
            using var outputFileWriter = File.OpenWrite("result.docx");
            responseStream.CopyTo(outputFileWriter);
          }
        }
        else
        {
          var responseStreamReader = new StreamReader(responseStream);
          Console.Write(responseStreamReader.ReadToEnd());
        }
      };

      client.Execute(request);
    }
  }
}

// This code requires Node.js. Do not run this code directly in a web browser.

const axios = require('axios')
const FormData = require('form-data')
const fs = require('fs')

const formData = new FormData()
formData.append('document', fs.createReadStream('template.docx'), {
  contentType: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
  filename: 'template.docx'
})
formData.append('model', JSON.stringify({
  name: 'Alex',
  company: 'Acme',
  date: '2026-04-10'
}))

;(async () => {
  try {
    const response = await axios.post('https://api.nutrient.io/process_office_template', formData, {
      headers: formData.getHeaders({
        'Authorization': 'Bearer your_api_key_here'
      }),
      responseType: 'stream'
    })

    response.data.pipe(fs.createWriteStream('result.docx'))
  } catch (e) {
    const errorString = await streamToString(e.response.data)
    console.log(errorString)
  }
})()

function streamToString(stream) {
  const chunks = []
  return new Promise((resolve, reject) => {
    stream.on('data', (chunk) => chunks.push(Buffer.from(chunk)))
    stream.on('error', (err) => reject(err))
    stream.on('end', () => resolve(Buffer.concat(chunks).toString('utf8')))
  })
}

import json
import requests

response = requests.request(
  'POST',
  'https://api.nutrient.io/process_office_template',
  headers = {
    'Authorization': 'Bearer your_api_key_here'
  },
  files = {
    'document': ('template.docx', open('template.docx', 'rb'), 'application/vnd.openxmlformats-officedocument.wordprocessingml.document')
  },
  data = {
    'model': json.dumps({
      'name': 'Alex',
      'company': 'Acme',
      'date': '2026-04-10'
    })
  },
  stream = True
)

if response.ok:
  with open('result.docx', 'wb') as fd:
    for chunk in response.iter_content(chunk_size=8096):
      fd.write(chunk)
else:
  print(response.text)
  exit()

<?php

$FileHandle = fopen('result.docx', 'w+');

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => 'https://api.nutrient.io/process_office_template',
  CURLOPT_CUSTOMREQUEST => 'POST',
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => '',
  CURLOPT_POSTFIELDS => array(
    'document' => new CURLFILE('template.docx', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document', 'template.docx'),
    'model' => '{
      "name": "Alex",
      "company": "Acme",
      "date": "2026-04-10"
    }'
  ),
  CURLOPT_HTTPHEADER => array(
    'Authorization: Bearer your_api_key_here'
  ),
  CURLOPT_FILE => $FileHandle,
));

$response = curl_exec($curl);

curl_close($curl);

fclose($FileHandle);

POST https://api.nutrient.io/process_office_template HTTP/1.1
Content-Type: multipart/form-data; boundary=--customboundary
Authorization: Bearer your_api_key_here

--customboundary
Content-Disposition: form-data; name="document"; filename="template.docx"
Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document

(template.docx data)
--customboundary
Content-Disposition: form-data; name="model"

{"name":"Alex","company":"Acme","date":"2026-04-10"}
--customboundary--

curl -X POST https://api.nutrient.io/process_office_template \
  -H "Authorization: Bearer your_api_key_here" \
  -o result.docx \
  --fail \
  -F 'document=@template.docx;type=application/vnd.openxmlformats-officedocument.wordprocessingml.document' \
  -F 'model={"config":{"delimiter":{"start":"{{","end":"}}"}},"model":{"name":"Alex","company":"Acme","date":"2026-04-10"}}'

curl -X POST https://api.nutrient.io/process_office_template ^
  -H "Authorization: Bearer your_api_key_here" ^
  -o result.docx ^
  --fail ^
  -F "document=@template.docx;type=application/vnd.openxmlformats-officedocument.wordprocessingml.document" ^
  -F "model={\"config\":{\"delimiter\":{\"start\":\"{{\",\"end\":\"}}\"}},\"model\":{\"name\":\"Alex\",\"company\":\"Acme\",\"date\":\"2026-04-10\"}}"

package com.example.pspdfkit;

import java.io.File;
import java.io.IOException;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;

import org.json.JSONObject;

import okhttp3.MediaType;
import okhttp3.MultipartBody;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public final class PspdfkitApiExample {
  public static void main(final String[] args) throws IOException {
    final MediaType mediaType = MediaType.parse("application/vnd.openxmlformats-officedocument.wordprocessingml.document");
    final JSONObject model = new JSONObject()
      .put("config", new JSONObject()
        .put("delimiter", new JSONObject()
          .put("start", "{{")
          .put("end", "}}")
        )
      )
      .put("model", new JSONObject()
        .put("name", "Alex")
        .put("company", "Acme")
        .put("date", "2026-04-10")
      );

    final RequestBody body = new MultipartBody.Builder()
      .setType(MultipartBody.FORM)
      .addFormDataPart(
        "document",
        "template.docx",
        RequestBody.create(
          mediaType,
          new File("template.docx")
        )
      )
      .addFormDataPart("model", model.toString())
      .build();

    final Request request = new Request.Builder()
      .url("https://api.nutrient.io/process_office_template")
      .method("POST", body)
      .addHeader("Authorization", "Bearer your_api_key_here")
      .build();

    final OkHttpClient client = new OkHttpClient()
      .newBuilder()
      .build();

    final Response response = client.newCall(request).execute();

    if (response.isSuccessful()) {
      Files.copy(
        response.body().byteStream(),
        FileSystems.getDefault().getPath("result.docx"),
        StandardCopyOption.REPLACE_EXISTING
      );
    } else {
      throw new IOException(response.body().string());
    }
  }
}

using System;
using System.IO;
using System.Net;
using RestSharp;

namespace PspdfkitApiDemo
{
  class Program
  {
    static void Main(string[] args)
    {
      var client = new RestClient("https://api.nutrient.io/process_office_template");

      var request = new RestRequest(Method.POST)
        .AddHeader("Authorization", "Bearer your_api_key_here")
        .AddFile("document", "template.docx")
        .AddParameter("model", new JsonObject
        {
          ["config"] = new JsonObject
          {
            ["delimiter"] = new JsonObject
            {
              ["start"] = "{{",
              ["end"] = "}}"
            }
          },
          ["model"] = new JsonObject
          {
            ["name"] = "Alex",
            ["company"] = "Acme",
            ["date"] = "2026-04-10"
          }
        }.ToString());

      request.AdvancedResponseWriter = (responseStream, response) =>
      {
        if (response.StatusCode == HttpStatusCode.OK)
        {
          using (responseStream)
          {
            using var outputFileWriter = File.OpenWrite("result.docx");
            responseStream.CopyTo(outputFileWriter);
          }
        }
        else
        {
          var responseStreamReader = new StreamReader(responseStream);
          Console.Write(responseStreamReader.ReadToEnd());
        }
      };

      client.Execute(request);
    }
  }
}

// This code requires Node.js. Do not run this code directly in a web browser.

const axios = require('axios')
const FormData = require('form-data')
const fs = require('fs')

const formData = new FormData()
formData.append('document', fs.createReadStream('template.docx'), {
  contentType: 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
  filename: 'template.docx'
})
formData.append('model', JSON.stringify({
  config: {
    delimiter: {
      start: '{{',
      end: '}}'
    }
  },
  model: {
    name: 'Alex',
    company: 'Acme',
    date: '2026-04-10'
  }
}))

;(async () => {
  try {
    const response = await axios.post('https://api.nutrient.io/process_office_template', formData, {
      headers: formData.getHeaders({
        'Authorization': 'Bearer your_api_key_here'
      }),
      responseType: 'stream'
    })

    response.data.pipe(fs.createWriteStream('result.docx'))
  } catch (e) {
    const errorString = await streamToString(e.response.data)
    console.log(errorString)
  }
})()

function streamToString(stream) {
  const chunks = []
  return new Promise((resolve, reject) => {
    stream.on('data', (chunk) => chunks.push(Buffer.from(chunk)))
    stream.on('error', (err) => reject(err))
    stream.on('end', () => resolve(Buffer.concat(chunks).toString('utf8')))
  })
}

import json
import requests

response = requests.request(
  'POST',
  'https://api.nutrient.io/process_office_template',
  headers = {
    'Authorization': 'Bearer your_api_key_here'
  },
  files = {
    'document': ('template.docx', open('template.docx', 'rb'), 'application/vnd.openxmlformats-officedocument.wordprocessingml.document')
  },
  data = {
    'model': json.dumps({
      'config': {
        'delimiter': {
          'start': '{{',
          'end': '}}'
        }
      },
      'model': {
        'name': 'Alex',
        'company': 'Acme',
        'date': '2026-04-10'
      }
    })
  },
  stream = True
)

if response.ok:
  with open('result.docx', 'wb') as fd:
    for chunk in response.iter_content(chunk_size=8096):
      fd.write(chunk)
else:
  print(response.text)
  exit()

<?php

$FileHandle = fopen('result.docx', 'w+');

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => 'https://api.nutrient.io/process_office_template',
  CURLOPT_CUSTOMREQUEST => 'POST',
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => '',
  CURLOPT_POSTFIELDS => array(
    'document' => new CURLFILE('template.docx', 'application/vnd.openxmlformats-officedocument.wordprocessingml.document', 'template.docx'),
    'model' => '{
      "config": {
        "delimiter": {
          "start": "{{",
          "end": "}}"
        }
      },
      "model": {
        "name": "Alex",
        "company": "Acme",
        "date": "2026-04-10"
      }
    }'
  ),
  CURLOPT_HTTPHEADER => array(
    'Authorization: Bearer your_api_key_here'
  ),
  CURLOPT_FILE => $FileHandle,
));

$response = curl_exec($curl);

curl_close($curl);

fclose($FileHandle);

POST https://api.nutrient.io/process_office_template HTTP/1.1
Content-Type: multipart/form-data; boundary=--customboundary
Authorization: Bearer your_api_key_here

--customboundary
Content-Disposition: form-data; name="document"; filename="template.docx"
Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document

(template.docx data)
--customboundary
Content-Disposition: form-data; name="model"

{"config":{"delimiter":{"start":"{{","end":"}}"}},"model":{"name":"Alex","company":"Acme","date":"2026-04-10"}}
--customboundary--

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Use the following:

DOCX-to-PDF API If the generated Word document also needs PDF output afterward

Office-to-PDF API For broader Word, Excel, and PowerPoint conversion workflows

Get started:

Getting started For API key setup

Postman collection For the fastest first request

REST API reference For endpoint details

Platform resources:

Processor API pricing For credits

Security documentation For document-handling and compliance review

Privacy documentation For data-handling review

Processor API overview For broader DWS evaluation of generation and automation workflows

Security is our top priority

No document storage

No input or resulting documents are stored on our infrastructure. All files are deleted as soon as a request finishes. Alternatively, check out our self-hosted product.

HTTPS encryption

All communication between your application and Nutrient is done via HTTPS to ensure your data is encrypted when it’s sent to us.

Safe payment processing

All payments are handled by Paddle. Nutrient DWS Processor API never has direct access to any of your payment data.

Start generating Word documents from templates through one hosted API

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