# Add a text watermark to a PDF

Stamp up to three lines of text across the pages of a PDF, with control over the template, color, and opacity.

Add a text watermark to a PDF document. Supply up to three lines of text and
control the template, color, transparency, and margin. By default the watermark
is stamped on every page. Use the [`pages`](#selecting-pages) parameter to
target a subset. The API is stateless: your document is processed in-region and
never stored.

## Endpoint

<Endpoint method="POST" path="/v1/add_text_watermark" />

Available in every region. See [Regions & data residency](/docs/api/regions-and-data-residency)
for routing and data residency.

| Region         | URL                                                 |
| -------------- | --------------------------------------------------- |
| Global         | `https://api.pdfblocks.com/v1/add_text_watermark`   |
| United States  | `https://us.api.pdfblocks.com/v1/add_text_watermark` |
| US HIPAA       | `https://hipaa.api.pdfblocks.com/v1/add_text_watermark` |
| European Union | `https://eu.api.pdfblocks.com/v1/add_text_watermark` |
| United Kingdom | `https://uk.api.pdfblocks.com/v1/add_text_watermark` |
| Canada         | `https://ca.api.pdfblocks.com/v1/add_text_watermark` |
| Australia      | `https://au.api.pdfblocks.com/v1/add_text_watermark` |
| Japan          | `https://jp.api.pdfblocks.com/v1/add_text_watermark` |
| India          | `https://in.api.pdfblocks.com/v1/add_text_watermark` |
| Brazil         | `https://br.api.pdfblocks.com/v1/add_text_watermark` |

## Authentication

Authenticate every request with your secret API key in the `X-API-Key` header,
over HTTPS. Create and manage keys from the
[dashboard](https://dashboard.pdfblocks.com). See
[Authentication](/docs/api/authentication) for details.

## Request

The endpoint accepts a `multipart/form-data` request body.

<ParamField name="file" type="file" required>
  The input PDF document.
</ParamField>

<ParamField name="line_1" type="string" required>
  The first line of watermark text. Maximum 32 characters. Use standard Latin
  characters.
</ParamField>

<ParamField name="line_2" type="string">
  The second line of watermark text. Maximum 32 characters.
</ParamField>

<ParamField name="line_3" type="string">
  The third line of watermark text. Maximum 32 characters.
</ParamField>

<ParamField name="pages" type="string">
  The pages to stamp, written as a [page range](#selecting-pages) such as
  `1..3,5`. When omitted, the watermark is applied to every page. Maximum 1000
  characters.
</ParamField>

<ParamField name="template" type="integer" default="1001">
  The watermark [template](#watermark-templates), which sets the style (filled or
  outline) and orientation.
</ParamField>

<ParamField name="color" type="string" default="Gray">
  The watermark [color](#colors). One of `Red`, `Blue`, `Gray`, or `Black`.
</ParamField>

<ParamField name="transparency" type="integer" default="75">
  The transparency level, from `0` (fully opaque) to `100` (fully transparent).
</ParamField>

<ParamField name="margin" type="decimal" default="1.0">
  The distance, in inches, from the page border to the watermark. `0` or greater.
</ParamField>

### Watermark templates

Each `template` combines a **style** (filled or outline) with an
**orientation**. Pass the ID to the `template` parameter.

| Template | Style   | Orientation                                    |
| -------- | ------- | ---------------------------------------------- |
| `1001`   | Filled  | Diagonal, bottom-left to top-right *(default)* |
| `1002`   | Filled  | Diagonal, top-left to bottom-right             |
| `1003`   | Filled  | Horizontal                                     |
| `1004`   | Filled  | Vertical, reading upward                       |
| `1005`   | Filled  | Vertical, reading downward                     |
| `1017`   | Outline | Diagonal, bottom-left to top-right             |
| `1018`   | Outline | Diagonal, top-left to bottom-right             |
| `1019`   | Outline | Horizontal                                     |
| `1020`   | Outline | Vertical, reading upward                       |
| `1021`   | Outline | Vertical, reading downward                     |

<Tip>
  See every template rendered on a sample page in the
  [visual template catalog](https://pdfblocks.com/assets/documents/pdfblocks-watermark-templates.pdf).
</Tip>

### Colors

| Value   | Swatch    |
| ------- | --------- |
| `Red`   | `#C00000` |
| `Blue`  | `#005DFF` |
| `Gray`  | `#545454` |
| `Black` | `#000000` |

### Selecting pages

The `pages` parameter takes a comma-separated list of 1-based page numbers and
ranges. It is treated as a **set**: order and duplicates are ignored, and pages
are always stamped in document order.

| Pattern   | Selects                                    |
| --------- | ------------------------------------------ |
| *(omit)*  | Every page                                 |
| `1`       | The first page only                        |
| `1..3,5`  | Pages 1, 2, 3, and 5                       |
| `2..`     | Page 2 through the last page               |
| `..-2`    | The first page through the second-to-last  |
| `-1`      | The last page                              |

See [Selecting pages](/docs/api/selecting-pages) for the complete reference.

## Examples

Stamp a two-line watermark on pages 1–3 and 5:

<CodeGroup>

```bash title="cURL"
curl https://api.pdfblocks.com/v1/add_text_watermark \
  -H 'X-API-Key: your_api_key' \
  -F file=@input.pdf \
  -F line_1='CONFIDENTIAL' \
  -F line_2='ACME, Inc.' \
  -F template=1001 \
  -F color=Red \
  -F pages='1..3,5' \
  -o watermarked.pdf
```

```python title="Python"
# pip install requests
import requests

with open('input.pdf', 'rb') as file:
    response = requests.post(
        'https://api.pdfblocks.com/v1/add_text_watermark',
        headers={'X-API-Key': 'your_api_key'},
        files={'file': file},
        data={
            'line_1': 'CONFIDENTIAL',
            'line_2': 'ACME, Inc.',
            'template': 1001,
            'color': 'Red',
            'pages': '1..3,5',
        },
    )

response.raise_for_status()
with open('watermarked.pdf', 'wb') as output:
    output.write(response.content)
```

```javascript title="Node.js"
// Node.js 18+
import { readFile, writeFile } from 'node:fs/promises';

const body = new FormData();
body.set('file', new Blob([await readFile('input.pdf')]), 'input.pdf');
body.set('line_1', 'CONFIDENTIAL');
body.set('line_2', 'ACME, Inc.');
body.set('template', '1001');
body.set('color', 'Red');
body.set('pages', '1..3,5');

const response = await fetch('https://api.pdfblocks.com/v1/add_text_watermark', {
  method: 'POST',
  headers: { 'X-API-Key': 'your_api_key' },
  body,
});

if (!response.ok) throw new Error(`Request failed: ${response.status}`);
await writeFile('watermarked.pdf', Buffer.from(await response.arrayBuffer()));
```

```php title="PHP"
<?php
$ch = curl_init('https://api.pdfblocks.com/v1/add_text_watermark');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['X-API-Key: your_api_key'],
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => [
        'file' => new CURLFile('input.pdf', 'application/pdf'),
        'line_1' => 'CONFIDENTIAL',
        'line_2' => 'ACME, Inc.',
        'template' => '1001',
        'color' => 'Red',
        'pages' => '1..3,5',
    ],
]);

$pdf = curl_exec($ch);
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) === 200) {
    file_put_contents('watermarked.pdf', $pdf);
}
```

```ruby title="Ruby"
# gem install http
require 'http'

response = HTTP
  .headers('X-API-Key' => 'your_api_key')
  .post('https://api.pdfblocks.com/v1/add_text_watermark', form: {
    file: HTTP::FormData::File.new('input.pdf'),
    line_1: 'CONFIDENTIAL',
    line_2: 'ACME, Inc.',
    template: '1001',
    color: 'Red',
    pages: '1..3,5',
  })

File.write('watermarked.pdf', response.body) if response.status.success?
```

```go title="Go"
package main

import (
	"bytes"
	"io"
	"mime/multipart"
	"net/http"
	"os"
)

func main() {
	var buf bytes.Buffer
	form := multipart.NewWriter(&buf)

	file, _ := os.Open("input.pdf")
	defer file.Close()
	part, _ := form.CreateFormFile("file", "input.pdf")
	io.Copy(part, file)

	form.WriteField("line_1", "CONFIDENTIAL")
	form.WriteField("line_2", "ACME, Inc.")
	form.WriteField("template", "1001")
	form.WriteField("color", "Red")
	form.WriteField("pages", "1..3,5")
	form.Close()

	req, _ := http.NewRequest("POST", "https://api.pdfblocks.com/v1/add_text_watermark", &buf)
	req.Header.Set("Content-Type", form.FormDataContentType())
	req.Header.Set("X-API-Key", "your_api_key")

	res, _ := http.DefaultClient.Do(req)
	defer res.Body.Close()

	out, _ := os.Create("watermarked.pdf")
	defer out.Close()
	io.Copy(out, res.Body)
}
```

```csharp title="C#"
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "your_api_key");

using var form = new MultipartFormDataContent
{
    { new ByteArrayContent(File.ReadAllBytes("input.pdf")), "file", "input.pdf" },
    { new StringContent("CONFIDENTIAL"), "line_1" },
    { new StringContent("ACME, Inc."), "line_2" },
    { new StringContent("1001"), "template" },
    { new StringContent("Red"), "color" },
    { new StringContent("1..3,5"), "pages" },
};

var response = await client.PostAsync(
    "https://api.pdfblocks.com/v1/add_text_watermark", form);
response.EnsureSuccessStatusCode();
await File.WriteAllBytesAsync(
    "watermarked.pdf", await response.Content.ReadAsByteArrayAsync());
```

</CodeGroup>

## Response

On success, the response is `200 OK` with the watermarked PDF as the body:

```http
HTTP/1.1 200 OK
Content-Type: application/pdf
Content-Length: 48213
```

The output preserves the input's page count and dimensions: only the watermark
is added. Stream the body straight to a file, as the examples above do; nothing
is stored on our side.

## Errors

Failed requests return an `application/problem+json` body. The most common one
for this endpoint is a `400`, returned when a parameter is invalid or `file`
isn't a readable PDF. The `errors` object names each field:

```json
{
  "type": "https://www.pdfblocks.com/docs/api/v1/error/400",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "errors": {
    "line_1": ["The field line_1 must be a string with a maximum length of 32."]
  }
}
```

A missing or invalid `X-API-Key` returns a `401`. See
[Errors](/docs/api/errors) for every status code and the full response shape.

## Recipes

Common variations. Expand one to see it in every language.

<AccordionGroup>

<Accordion title="A bold red DRAFT across every page">

<CodeGroup>

```bash title="cURL"
curl https://api.pdfblocks.com/v1/add_text_watermark \
  -H 'X-API-Key: your_api_key' \
  -F file=@input.pdf \
  -F line_1='DRAFT' \
  -F color=Red \
  -F template=1001 \
  -F transparency=40 \
  -o draft.pdf
```

```python title="Python"
import requests

with open('input.pdf', 'rb') as file:
    response = requests.post(
        'https://api.pdfblocks.com/v1/add_text_watermark',
        headers={'X-API-Key': 'your_api_key'},
        files={'file': file},
        data={'line_1': 'DRAFT', 'color': 'Red', 'template': 1001, 'transparency': 40},
    )

response.raise_for_status()
with open('draft.pdf', 'wb') as output:
    output.write(response.content)
```

```javascript title="Node.js"
import { readFile, writeFile } from 'node:fs/promises';

const body = new FormData();
body.set('file', new Blob([await readFile('input.pdf')]), 'input.pdf');
body.set('line_1', 'DRAFT');
body.set('color', 'Red');
body.set('template', '1001');
body.set('transparency', '40');

const response = await fetch('https://api.pdfblocks.com/v1/add_text_watermark', {
  method: 'POST',
  headers: { 'X-API-Key': 'your_api_key' },
  body,
});

if (!response.ok) throw new Error(`Request failed: ${response.status}`);
await writeFile('draft.pdf', Buffer.from(await response.arrayBuffer()));
```

```php title="PHP"
<?php
$ch = curl_init('https://api.pdfblocks.com/v1/add_text_watermark');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['X-API-Key: your_api_key'],
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => [
        'file' => new CURLFile('input.pdf', 'application/pdf'),
        'line_1' => 'DRAFT',
        'color' => 'Red',
        'template' => '1001',
        'transparency' => '40',
    ],
]);

$pdf = curl_exec($ch);
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) === 200) {
    file_put_contents('draft.pdf', $pdf);
}
```

```ruby title="Ruby"
require 'http'

response = HTTP
  .headers('X-API-Key' => 'your_api_key')
  .post('https://api.pdfblocks.com/v1/add_text_watermark', form: {
    file: HTTP::FormData::File.new('input.pdf'),
    line_1: 'DRAFT',
    color: 'Red',
    template: '1001',
    transparency: '40',
  })

File.write('draft.pdf', response.body) if response.status.success?
```

```go title="Go"
package main

import (
	"bytes"
	"io"
	"mime/multipart"
	"net/http"
	"os"
)

func main() {
	var buf bytes.Buffer
	form := multipart.NewWriter(&buf)

	file, _ := os.Open("input.pdf")
	defer file.Close()
	part, _ := form.CreateFormFile("file", "input.pdf")
	io.Copy(part, file)

	form.WriteField("line_1", "DRAFT")
	form.WriteField("color", "Red")
	form.WriteField("template", "1001")
	form.WriteField("transparency", "40")
	form.Close()

	req, _ := http.NewRequest("POST", "https://api.pdfblocks.com/v1/add_text_watermark", &buf)
	req.Header.Set("Content-Type", form.FormDataContentType())
	req.Header.Set("X-API-Key", "your_api_key")

	res, _ := http.DefaultClient.Do(req)
	defer res.Body.Close()

	out, _ := os.Create("draft.pdf")
	defer out.Close()
	io.Copy(out, res.Body)
}
```

```csharp title="C#"
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "your_api_key");

using var form = new MultipartFormDataContent
{
    { new ByteArrayContent(File.ReadAllBytes("input.pdf")), "file", "input.pdf" },
    { new StringContent("DRAFT"), "line_1" },
    { new StringContent("Red"), "color" },
    { new StringContent("1001"), "template" },
    { new StringContent("40"), "transparency" },
};

var response = await client.PostAsync(
    "https://api.pdfblocks.com/v1/add_text_watermark", form);
response.EnsureSuccessStatusCode();
await File.WriteAllBytesAsync(
    "draft.pdf", await response.Content.ReadAsByteArrayAsync());
```

</CodeGroup>

</Accordion>

<Accordion title="An outline CONFIDENTIAL on the cover page">

<CodeGroup>

```bash title="cURL"
curl https://api.pdfblocks.com/v1/add_text_watermark \
  -H 'X-API-Key: your_api_key' \
  -F file=@input.pdf \
  -F line_1='CONFIDENTIAL' \
  -F template=1017 \
  -F pages='1' \
  -o confidential.pdf
```

```python title="Python"
import requests

with open('input.pdf', 'rb') as file:
    response = requests.post(
        'https://api.pdfblocks.com/v1/add_text_watermark',
        headers={'X-API-Key': 'your_api_key'},
        files={'file': file},
        data={'line_1': 'CONFIDENTIAL', 'template': 1017, 'pages': '1'},
    )

response.raise_for_status()
with open('confidential.pdf', 'wb') as output:
    output.write(response.content)
```

```javascript title="Node.js"
import { readFile, writeFile } from 'node:fs/promises';

const body = new FormData();
body.set('file', new Blob([await readFile('input.pdf')]), 'input.pdf');
body.set('line_1', 'CONFIDENTIAL');
body.set('template', '1017');
body.set('pages', '1');

const response = await fetch('https://api.pdfblocks.com/v1/add_text_watermark', {
  method: 'POST',
  headers: { 'X-API-Key': 'your_api_key' },
  body,
});

if (!response.ok) throw new Error(`Request failed: ${response.status}`);
await writeFile('confidential.pdf', Buffer.from(await response.arrayBuffer()));
```

```php title="PHP"
<?php
$ch = curl_init('https://api.pdfblocks.com/v1/add_text_watermark');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['X-API-Key: your_api_key'],
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => [
        'file' => new CURLFile('input.pdf', 'application/pdf'),
        'line_1' => 'CONFIDENTIAL',
        'template' => '1017',
        'pages' => '1',
    ],
]);

$pdf = curl_exec($ch);
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) === 200) {
    file_put_contents('confidential.pdf', $pdf);
}
```

```ruby title="Ruby"
require 'http'

response = HTTP
  .headers('X-API-Key' => 'your_api_key')
  .post('https://api.pdfblocks.com/v1/add_text_watermark', form: {
    file: HTTP::FormData::File.new('input.pdf'),
    line_1: 'CONFIDENTIAL',
    template: '1017',
    pages: '1',
  })

File.write('confidential.pdf', response.body) if response.status.success?
```

```go title="Go"
package main

import (
	"bytes"
	"io"
	"mime/multipart"
	"net/http"
	"os"
)

func main() {
	var buf bytes.Buffer
	form := multipart.NewWriter(&buf)

	file, _ := os.Open("input.pdf")
	defer file.Close()
	part, _ := form.CreateFormFile("file", "input.pdf")
	io.Copy(part, file)

	form.WriteField("line_1", "CONFIDENTIAL")
	form.WriteField("template", "1017")
	form.WriteField("pages", "1")
	form.Close()

	req, _ := http.NewRequest("POST", "https://api.pdfblocks.com/v1/add_text_watermark", &buf)
	req.Header.Set("Content-Type", form.FormDataContentType())
	req.Header.Set("X-API-Key", "your_api_key")

	res, _ := http.DefaultClient.Do(req)
	defer res.Body.Close()

	out, _ := os.Create("confidential.pdf")
	defer out.Close()
	io.Copy(out, res.Body)
}
```

```csharp title="C#"
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "your_api_key");

using var form = new MultipartFormDataContent
{
    { new ByteArrayContent(File.ReadAllBytes("input.pdf")), "file", "input.pdf" },
    { new StringContent("CONFIDENTIAL"), "line_1" },
    { new StringContent("1017"), "template" },
    { new StringContent("1"), "pages" },
};

var response = await client.PostAsync(
    "https://api.pdfblocks.com/v1/add_text_watermark", form);
response.EnsureSuccessStatusCode();
await File.WriteAllBytesAsync(
    "confidential.pdf", await response.Content.ReadAsByteArrayAsync());
```

</CodeGroup>

</Accordion>

<Accordion title="A subtle gray notice on every page but the last">

<CodeGroup>

```bash title="cURL"
curl https://api.pdfblocks.com/v1/add_text_watermark \
  -H 'X-API-Key: your_api_key' \
  -F file=@input.pdf \
  -F line_1='ACME, Inc.' \
  -F line_2='Do not distribute' \
  -F color=Gray \
  -F transparency=88 \
  -F pages='..-2' \
  -o notice.pdf
```

```python title="Python"
import requests

with open('input.pdf', 'rb') as file:
    response = requests.post(
        'https://api.pdfblocks.com/v1/add_text_watermark',
        headers={'X-API-Key': 'your_api_key'},
        files={'file': file},
        data={
            'line_1': 'ACME, Inc.',
            'line_2': 'Do not distribute',
            'color': 'Gray',
            'transparency': 88,
            'pages': '..-2',
        },
    )

response.raise_for_status()
with open('notice.pdf', 'wb') as output:
    output.write(response.content)
```

```javascript title="Node.js"
import { readFile, writeFile } from 'node:fs/promises';

const body = new FormData();
body.set('file', new Blob([await readFile('input.pdf')]), 'input.pdf');
body.set('line_1', 'ACME, Inc.');
body.set('line_2', 'Do not distribute');
body.set('color', 'Gray');
body.set('transparency', '88');
body.set('pages', '..-2');

const response = await fetch('https://api.pdfblocks.com/v1/add_text_watermark', {
  method: 'POST',
  headers: { 'X-API-Key': 'your_api_key' },
  body,
});

if (!response.ok) throw new Error(`Request failed: ${response.status}`);
await writeFile('notice.pdf', Buffer.from(await response.arrayBuffer()));
```

```php title="PHP"
<?php
$ch = curl_init('https://api.pdfblocks.com/v1/add_text_watermark');
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => ['X-API-Key: your_api_key'],
    CURLOPT_POST => true,
    CURLOPT_POSTFIELDS => [
        'file' => new CURLFile('input.pdf', 'application/pdf'),
        'line_1' => 'ACME, Inc.',
        'line_2' => 'Do not distribute',
        'color' => 'Gray',
        'transparency' => '88',
        'pages' => '..-2',
    ],
]);

$pdf = curl_exec($ch);
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) === 200) {
    file_put_contents('notice.pdf', $pdf);
}
```

```ruby title="Ruby"
require 'http'

response = HTTP
  .headers('X-API-Key' => 'your_api_key')
  .post('https://api.pdfblocks.com/v1/add_text_watermark', form: {
    file: HTTP::FormData::File.new('input.pdf'),
    line_1: 'ACME, Inc.',
    line_2: 'Do not distribute',
    color: 'Gray',
    transparency: '88',
    pages: '..-2',
  })

File.write('notice.pdf', response.body) if response.status.success?
```

```go title="Go"
package main

import (
	"bytes"
	"io"
	"mime/multipart"
	"net/http"
	"os"
)

func main() {
	var buf bytes.Buffer
	form := multipart.NewWriter(&buf)

	file, _ := os.Open("input.pdf")
	defer file.Close()
	part, _ := form.CreateFormFile("file", "input.pdf")
	io.Copy(part, file)

	form.WriteField("line_1", "ACME, Inc.")
	form.WriteField("line_2", "Do not distribute")
	form.WriteField("color", "Gray")
	form.WriteField("transparency", "88")
	form.WriteField("pages", "..-2")
	form.Close()

	req, _ := http.NewRequest("POST", "https://api.pdfblocks.com/v1/add_text_watermark", &buf)
	req.Header.Set("Content-Type", form.FormDataContentType())
	req.Header.Set("X-API-Key", "your_api_key")

	res, _ := http.DefaultClient.Do(req)
	defer res.Body.Close()

	out, _ := os.Create("notice.pdf")
	defer out.Close()
	io.Copy(out, res.Body)
}
```

```csharp title="C#"
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("X-API-Key", "your_api_key");

using var form = new MultipartFormDataContent
{
    { new ByteArrayContent(File.ReadAllBytes("input.pdf")), "file", "input.pdf" },
    { new StringContent("ACME, Inc."), "line_1" },
    { new StringContent("Do not distribute"), "line_2" },
    { new StringContent("Gray"), "color" },
    { new StringContent("88"), "transparency" },
    { new StringContent("..-2"), "pages" },
};

var response = await client.PostAsync(
    "https://api.pdfblocks.com/v1/add_text_watermark", form);
response.EnsureSuccessStatusCode();
await File.WriteAllBytesAsync(
    "notice.pdf", await response.Content.ReadAsByteArrayAsync());
```

</CodeGroup>

</Accordion>

</AccordionGroup>

## Related actions

<CardGroup cols={2}>

<Card title="Add an image watermark" href="/docs/api/add-image-watermark-to-pdf">
  Stamp a logo or image instead of text.
</Card>

<Card title="Add a password" href="/docs/api/add-password-to-pdf">
  Encrypt the watermarked document.
</Card>

<Card title="Merge documents" href="/docs/api/merge-pdf-documents">
  Combine files before watermarking.
</Card>

<Card title="Add restrictions" href="/docs/api/add-restrictions-to-pdf">
  Limit printing, copying, and editing.
</Card>

</CardGroup>