---
name: "pdf123-add-attachments"
description: "Embed files (attachments) inside a PDF. Runs the PDF123 \"Add Attachments\" 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: 管理附件, Gestionar adjuntos, अटैचमेंट प्रबंधित करें, إدارة المرفقات, Adicionar anexos, Kelola lampiran, Gérer les pièces jointes, Вложения, 添付ファイルの管理, Anhänge verwalten, 첨부 관리, Quản lý tệp đính kèm, Ekleri yönet, Gestisci allegati, จัดการไฟล์แนบ, Załączniki, Вкладення, Bijlagen beheren, Urus lampiran, Lägg till bilagor, Διαχείριση συνημμένων, Прикачени файлове, Gestiona adjunts, Simamia viambatisho."
compatibility: "Needs curl 7.76+ and outbound HTTPS to pdf123.xyz, or PDFX_API_BASE pointing at a self-hosted pdfx-server."
---

# Add Attachments (PDF123)

Embed files (attachments) inside a PDF.

Web version: https://pdf123.xyz/add-attachments · All tools: https://pdf123.xyz/skills/pdf123.md

## When to use

- Clip a spreadsheet to a PDF cover letter
- Carry source files inside a PDF for a reviewer who uses Acrobat
- Skip the PDF/A-3 checkbox

## 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/misc/add-attachments" \
  -F "fileInput=@input.pdf" \
  -F "attachments=@attachments.pdf" \
  --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) |
| `attachments` | file | yes | | Files to attach (repeat for several) |

## 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

- Not PDF/A-3b
- Not Merge
- Viewers without an attachments pane hide the files
- 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`.