---
name: "pdf123-linearize-pdf"
description: "Optimize a PDF for fast web viewing (page-at-a-time streaming). Runs the PDF123 \"Linearize PDF\" 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: 线性化 PDF, Linealizar PDF, PDF रैखिक करें, خطّية PDF, Linearizar PDF, Linearisasi PDF, Linéariser le PDF, Линеаризовать PDF, ウェブ表示の最適化, PDF linearisieren, PDF 선형화, Tuyến tính hóa PDF, PDF doğrusallaştır, 線性化 PDF, Linearizza PDF, ปรับให้โหลดทีละหน้า, Linearyzuj PDF, Лінеаризувати PDF, PDF lineariseren, Linearisera PDF, Γραμμικοποίηση PDF, Линеализиране на PDF, Linealitza PDF, Panga PDF kwa wavuti."
compatibility: "Needs curl 7.76+ and outbound HTTPS to pdf123.xyz, or PDFX_API_BASE pointing at a self-hosted pdfx-server."
---

# Linearize PDF (PDF123)

Optimize a PDF for fast web viewing (page-at-a-time streaming).

Web version: https://pdf123.xyz/linearize-pdf · All tools: https://pdf123.xyz/skills/pdf123.md

## When to use

- Serve a large PDF page by page in a browser
- Hand a scanned report to a web viewer without a long blank wait
- Meet a portal's 'optimized for web' upload requirement

## 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/linearize-pdf" \
  -F "fileInput=@input.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) |

## 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

- Reorganises the file; it is not a size-reduction tool
- No image resampling
- Password-protected files need the password; API callers run Unlock first
- 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`.