Upload your PDF first, then optionally a second image or PDF as the background. Or set a solid color below.
How to Use
1Upload your PDF
2Choose a background color or upload a background image/PDF
3Click Add Background
4Download the updated PDF
About this tool
Updated
What is Add Background?
Add Background on Synthixx Tools is a free browser-based utility: upload your file, configure options, run the job, and download the result with no account and no watermark. Add a color or image background to PDF pages.
Add Background runs entirely in your browser session against our secure API. There is no desktop install, no watermark on outputs, and no requirement to create an account for standard jobs. Keep reading for when to use this tool, practical tips, and honest limits.
When should you use Add Background?
Use Add Background when your goal matches the tool name and you want a free online workflow with clear privacy cleanup. Prefer related tools on this site if you need a different step in the same document pipeline.
Pick Add Background when the primary keyword intent matches your task. For multi-step pipelines (OCR → compress → protect), run each step with the matching tool rather than expecting a single upload to do everything. Related tools are linked at the bottom of this page.
Tips for better results
For best results with Add Background: use clear filenames, stay within size limits listed in the upload UI, and preview pages when available before you run the job. Re-download promptly — outputs are temporary.
Stay within the upload limits shown in the tool UI. If a job fails, re-check file type and corruption (try Repair PDF). For password-protected inputs, unlock first. After success, download immediately and delete local copies you no longer need.
Privacy and file handling
Synthixx Tools processes files for your requested job only. Transfers use HTTPS; completed job files are scheduled for automatic deletion. We do not sell your documents.
Privacy-first processing is a core product rule: uploads are used to fulfill the tool job you start, not for advertising profiles. Do not upload highly sensitive materials to any free online tool unless your threat model allows it — that advice applies industry-wide, including competitors.
For account features (Design cloud sync), sign-in pages are noindexed; tool pages remain the public SEO surface.
Related workflows on Synthixx Tools
After Add Background, continue with related PDF or image tools on Synthixx — merge, split, compress, convert, OCR, protect, and AI PDF Studio — all free and linked from this page.
Internal workflows that often follow Add Background include compress for email size, protect for sharing, OCR for searchable archives, and AI PDF Studio for summaries or Q&A. Browse the PDF Tools category hub for the full catalog. Image Resizer and Image Compressor cover bitmap workflows when your output is a picture rather than a PDF.
Features
100% free — no account required
Solid color or image/PDF page background
Background placed behind existing content
Up to 200 MB per file
Privacy-first: encrypted upload, auto-delete after processing
Built by Synthixx Technologies
FAQ
Can I use a PDF as the background?
Yes. Upload your main PDF first, then a second PDF or PNG/JPEG as the background.
Are my files private?
Files are processed securely and automatically deleted after your job completes.