---
name: "pdf123-watermark"
description: "Add text or image watermarks to PDF files. Runs the PDF123 \"Add Watermark\" tool (pdf123.xyz) over its REST API with curl, no account needed. Use when the user wants this done to their file. Also known as: 添加水印, Añadir marca de agua, वॉटरमार्क लगाएँ, إضافة علامة مائية, Adicionar marca d'água, Tambah tanda air, Ajouter un filigrane, Водяной знак, 透かしの追加, Wasserzeichen, 워터마크 넣기, Thêm hình mờ, Filigran ekle, 加入浮水印, Aggiungi filigrana, ใส่ลายน้ำ, Dodaj znak wodny, Водяний знак, Watermerk toevoegen, Lägg till vattenmärke, Προσθήκη υδατογραφήματος, Воден знак, Afegeix marca d'aigua, Weka alama ya maji."
compatibility: "Needs curl 7.76+ and outbound HTTPS to pdf123.xyz, or PDFX_API_BASE pointing at a self-hosted pdfx-server."
---

# Add Watermark (PDF123)

Add text or image watermarks to PDF files.

Web version: https://pdf123.xyz/watermark · All tools: https://pdf123.xyz/skills/pdf123.md

## When to use

- Tile DRAFT across a review copy
- Mark a packet confidential in Latin letters
- Repeat a short phrase at 45 degrees

## Run it

Replace the sample file names and values with the user's, then run:

```bash
API="${PDFX_API_BASE:-https://pdf123.xyz}"
curl -sS --fail-with-body -X POST "$API/api/v1/security/add-watermark" \
  -F "fileInput=@input.pdf" \
  -F "watermarkText=PDF123" \
  -F "fontSize=30" \
  -F "rotation=45" \
  -F "customColor=#d3d3d3" \
  --output-dir "pdf123-output/$(date +%Y%m%d-%H%M%S)" --create-dirs -OJ -w '%{filename_effective} %{content_type}\n'
```

## Inputs

Everything is `multipart/form-data`. The command above already sends each field with its default; keep them all and change only the values the user asked for, since some endpoints reject a missing optional field.

| Field | Type | Required | Default | Notes |
| --- | --- | --- | --- | --- |
| `fileInput` | file | yes | | .pdf (one file) |
| `watermarkText` | text | no | `PDF123` | Watermark text |
| `fontSize` | number | no | `30` | Font size |
| `rotation` | number | no | `45` | Rotation (degrees) |
| `customColor` | color (#rrggbb) | no | `#d3d3d3` | Color |

## Result

curl saves the result in a new `pdf123-output/<timestamp>/` directory under the server's file name and prints its path and content type. Several output files come back as one ZIP. Tell the user where the file is.

## Limits

- Text only, in Helvetica (Latin characters)
- Applies to every page
- Does not make scanned text searchable
- Upload limit on this website: 500 MB per file, sent in chunks above about 95 MB. A single direct API request body is capped at 100 MB.

## Errors

- A non-zero curl exit means the request failed. The saved file then holds `application/problem+json`; read it and report its `detail` to the user instead of retrying blindly.
- `413`: the upload exceeds 100 MiB. `429`: wait for `Retry-After` seconds, then retry once.
- Send `X-API-KEY: $PDFX_API_KEY` only if the user has a PDF123 API key; anonymous calls work without it.

## Privacy

Files are uploaded to the API host, processed, and deleted once the response is sent. For confidential files, ask before uploading, or use a self-hosted server via `PDFX_API_BASE`.

## Authorized use only

Only watermark documents you own or are authorized to modify. Do not use marks to impersonate an official seal or to interfere with records you are required to keep unmarked.