PDF watermark API

Add custom text or image watermarks to PDF documents using a single API call. Use watermarking for branding, confidential stamps, ownership marks, document tracking, and other document-protection workflows.

Try for free

Text and image watermarking for protection and branding

Apply text or image watermarks such as company logos, confidential stamps, ownership marks, or custom messages to any page or section of a PDF.

Built for API-driven document workflows

Use REST, Postman, curl, JavaScript, Python, Java, C#, PHP, or HTTP to add watermarks in your own platform without building custom document-processing infrastructure.

Automate watermarking at scale

Use watermarking for branded exports, confidential document delivery, ownership labeling, and automated protection workflows across generated or uploaded PDFs.

Try it out

This example will watermark all the pages of your document with the supplied logo.

Try it out in three steps

Add document.pdf and logo.png to your project folder.
Run the code from the same folder.
Open result.pdf to see the output.

Advanced API

curl -X POST https://api.nutrient.io/processor/watermark \
  -H "Authorization: Bearer your_api_key_here" \
  -o result.pdf \
  --fail \
  -F file=@document.pdf \
  -F logo=@logo.png \
  -F data='{
      "image": "logo",
      "width": "25%"
    }'

curl -X POST https://api.nutrient.io/processor/watermark ^
  -H "Authorization: Bearer your_api_key_here" ^
  -o result.pdf ^
  --fail ^
  -F file=@document.pdf ^
  -F logo=@logo.png ^
  -F data="{\"image\": \"logo\", \"width\": \"25%\"}"

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.JSONArray;
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 RequestBody body = new MultipartBody.Builder()
      .setType(MultipartBody.FORM)
      .addFormDataPart(
        "file",
        "document.pdf",
        RequestBody.create(
          MediaType.parse("application/pdf"),
          new File("document.pdf")
        )
      )
      .addFormDataPart(
        "logo",
        "logo.png",
        RequestBody.create(
          MediaType.parse("image/png"),
          new File("logo.png")
        )
      )
      .addFormDataPart(
        "data",
        new JSONObject()
          .put("image", "logo")
          .put("width", "25%").toString()
      )
      .build();

    final Request request = new Request.Builder()
      .url("https://api.nutrient.io/processor/watermark")
      .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.pdf"),
        StandardCopyOption.REPLACE_EXISTING
      );
    } else {
      // Handle the error
      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/processor/watermark");

      var request = new RestRequest(Method.POST)
        .AddHeader("Authorization", "Bearer your_api_key_here")
        .AddFile("file", "document.pdf")
        .AddFile("logo", "logo.png")
        .AddParameter("data", new JsonObject
        {
          ["image"] = "logo",
          ["width"] = "25%"
        }.ToString());

      request.AdvancedResponseWriter = (responseStream, response) =>
      {
        if (response.StatusCode == HttpStatusCode.OK)
        {
          using (responseStream)
          {
            using var outputFileWriter = File.OpenWrite("result.pdf");
            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('data', JSON.stringify({
  image: "logo",
  width: "25%"
}))
formData.append('file', fs.createReadStream('document.pdf'))
formData.append('logo', fs.createReadStream('logo.png'))

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

    response.data.pipe(fs.createWriteStream("result.pdf"))
  } 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 requests
import json

response = requests.request(
  'POST',
  'https://api.nutrient.io/processor/watermark',
  headers = {
    'Authorization': 'Bearer your_api_key_here'
  },
  files = {
    'file': open('document.pdf', 'rb'),
    'logo': open('logo.png', 'rb')
  },
  data = {
    'data': json.dumps({
      'image': 'logo',
      'width': '25%'
    })
  },
  stream = True
)

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

<?php

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

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => 'https://api.nutrient.io/processor/watermark',
  CURLOPT_CUSTOMREQUEST => 'POST',
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => '',
  CURLOPT_POSTFIELDS => array(
    'data' => '{
      "image": "logo",
      "width": "25%"
    }',
    'file' => new CURLFILE('document.pdf'),
    'logo' => new CURLFILE('logo.png')
  ),
  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/processor/watermark HTTP/1.1
Content-Type: multipart/form-data; boundary=--customboundary
Authorization: Bearer your_api_key_here

--customboundary
Content-Disposition: form-data; name="data"
Content-Type: application/json

{
  "image": "logo",
  "width": "25%"
}
--customboundary
Content-Disposition: form-data; name="file"; filename="document.pdf"
Content-Type: application/pdf

(file data)
--customboundary
Content-Disposition: form-data; name="logo"; filename="logo.png"
Content-Type: image/png

(logo data)
--customboundary--

curl -X POST https://api.nutrient.io/build \
  -H "Authorization: Bearer your_api_key_here" \
  -o result.pdf \
  --fail \
  -F document=@document.pdf \
  -F logo=@logo.png \
  -F instructions='{
      "parts": [
        {
          "file": "document"
        }
      ],
      "actions": [
        {
          "type": "watermark",
          "image": "logo",
          "width": "25%"
        }
      ]
    }'

curl -X POST https://api.nutrient.io/build ^
  -H "Authorization: Bearer your_api_key_here" ^
  -o result.pdf ^
  --fail ^
  -F document=@document.pdf ^
  -F logo=@logo.png ^
  -F instructions="{\"parts\": [{\"file\": \"document\"}], \"actions\": [{\"type\": \"watermark\", \"image\": \"logo\", \"width\": \"25%\"}]}"

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.JSONArray;
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 RequestBody body = new MultipartBody.Builder()
      .setType(MultipartBody.FORM)
      .addFormDataPart(
        "document",
        "document.pdf",
        RequestBody.create(
          MediaType.parse("application/pdf"),
          new File("document.pdf")
        )
      )
      .addFormDataPart(
        "logo",
        "logo.png",
        RequestBody.create(
          MediaType.parse("image/png"),
          new File("logo.png")
        )
      )
      .addFormDataPart(
        "instructions",
        new JSONObject()
          .put("parts", new JSONArray()
            .put(new JSONObject()
              .put("file", "document")
            )
          )
          .put("actions", new JSONArray()
            .put(new JSONObject()
              .put("type", "watermark")
              .put("image", "logo")
              .put("width", "25%")
            )
          ).toString()
      )
      .build();

    final Request request = new Request.Builder()
      .url("https://api.nutrient.io/build")
      .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.pdf"),
        StandardCopyOption.REPLACE_EXISTING
      );
    } else {
      // Handle the error
      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/build");

      var request = new RestRequest(Method.POST)
        .AddHeader("Authorization", "Bearer your_api_key_here")
        .AddFile("document", "document.pdf")
        .AddFile("logo", "logo.png")
        .AddParameter("instructions", new JsonObject
        {
          ["parts"] = new JsonArray
          {
            new JsonObject
            {
              ["file"] = "document"
            }
          },
          ["actions"] = new JsonArray
          {
            new JsonObject
            {
              ["type"] = "watermark",
              ["image"] = "logo",
              ["width"] = "25%"
            }
          }
        }.ToString());

      request.AdvancedResponseWriter = (responseStream, response) =>
      {
        if (response.StatusCode == HttpStatusCode.OK)
        {
          using (responseStream)
          {
            using var outputFileWriter = File.OpenWrite("result.pdf");
            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('instructions', JSON.stringify({
  parts: [
    {
      file: "document"
    }
  ],
  actions: [
    {
      type: "watermark",
      image: "logo",
      width: "25%"
    }
  ]
}))
formData.append('document', fs.createReadStream('document.pdf'))
formData.append('logo', fs.createReadStream('logo.png'))

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

    response.data.pipe(fs.createWriteStream("result.pdf"))
  } 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 requests
import json

response = requests.request(
  'POST',
  'https://api.nutrient.io/build',
  headers = {
    'Authorization': 'Bearer your_api_key_here'
  },
  files = {
    'document': open('document.pdf', 'rb'),
    'logo': open('logo.png', 'rb')
  },
  data = {
    'instructions': json.dumps({
      'parts': [
        {
          'file': 'document'
        }
      ],
      'actions': [
        {
          'type': 'watermark',
          'image': 'logo',
          'width': '25%'
        }
      ]
    })
  },
  stream = True
)

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

<?php

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

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => 'https://api.nutrient.io/build',
  CURLOPT_CUSTOMREQUEST => 'POST',
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => '',
  CURLOPT_POSTFIELDS => array(
    'instructions' => '{
      "parts": [
        {
          "file": "document"
        }
      ],
      "actions": [
        {
          "type": "watermark",
          "image": "logo",
          "width": "25%"
        }
      ]
    }',
    'document' => new CURLFILE('document.pdf'),
    'logo' => new CURLFILE('logo.png')
  ),
  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/build HTTP/1.1
Content-Type: multipart/form-data; boundary=--customboundary
Authorization: Bearer your_api_key_here

--customboundary
Content-Disposition: form-data; name="instructions"
Content-Type: application/json

{
  "parts": [
    {
      "file": "document"
    }
  ],
  "actions": [
    {
      "type": "watermark",
      "image": "logo",
      "width": "25%"
    }
  ]
}
--customboundary
Content-Disposition: form-data; name="document"; filename="document.pdf"
Content-Type: application/pdf

(document data)
--customboundary
Content-Disposition: form-data; name="logo"; filename="logo.png"
Content-Type: image/png

(logo data)
--customboundary--

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Implementation options

Validate text and image watermark workflows before deeper integration

Teams evaluating watermarking usually need to confirm both the styling flexibility and the easiest integration path. Nutrient supports REST, Postman, curl, JavaScript, Python, Java, C#, PHP, and raw HTTP so developers can test text and image watermark workflows before connecting them to branded exports, confidential delivery, or document-protection systems.

OPEN WATERMARK GUIDE

Continue to:

Getting started For API key setup

Postman collection For the fastest first request

Processor API pricing For credits

Processor API overview For broader DWS evaluation of image watermark, branding, and confidential watermark workflows

API comparison

BASIC

Watermark API

Straightforward API for adding watermarks to PDFs. Perfect for most use cases.

FEATURES

Simple request format
Minimal configuration required
Purpose-built for specific tasks

ADVANCED

Build API

Maximum flexibility and advanced features for complex workflows.

FEATURES

Multipart document support
Advanced actions and transformations
Workflow orchestration

Getting started

The following section will walk you through how to best make use of all the functionality the watermark API provides.

GUIDES

Multiple watermarks

Single-page watermark

Aligning watermarks

Reference

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.

Ready to try it?

Create an account to get your DWS Processor API key and start making API calls.

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