Upload two PDF versions and instantly see every change highlighted - additions in green, deletions in red. Perfect for contract review and document version tracking.
Upload Original
Drop or click to browse
PDF files only · up to 100 MB
Upload Revised
Drop or click to browse
PDF files only · up to 100 MB
Upload both PDFs above to begin - the original version and the revised version
How it works
No software to install. Works on any device with a modern browser.
Drop the original PDF into the left panel and the revised PDF into the right. Previews load instantly so you can confirm you have the right files.
Both files are uploaded simultaneously. SupaPDF analyses every page, matching text blocks and identifying what was added, removed, or changed.
The result is a single PDF with pages interleaved: Original page 1 (red highlights) → Revised page 1 (green highlights) → Original page 2 → …
Why SupaPDF
Used by legal, editorial, and engineering teams worldwide to track document changes.
Both PDFs render side by side with a synchronised page navigator. Navigate to any page on both documents simultaneously to confirm you have the right versions.
All uploads use encrypted HTTPS. Both files are permanently deleted from our servers immediately after your download is complete.
Changes are overlaid as vector annotations - not rasterised images. Text in the output remains fully selectable and searchable.
Automate PDF comparison in your pipeline. Upload two files to separate import tasks and pass both as inputs to compare_pdfs - one REST call.
Developer API
Create two import/upload tasks, pass both as input to compare_pdfs, and upload the files in parallel. No extra parameters needed.
# Step 1: Create the job with two import tasks
curl -X POST https://api.supapdf.com/v1/jobs \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"tag": "compare-pdf-job",
"tasks": {
"upload-original": { "operation": "import/upload" },
"upload-revised": { "operation": "import/upload" },
"compare-0": {
"operation": "compare_pdfs",
"input": ["upload-original", "upload-revised"]
},
"export-result": { "operation": "export/url", "input": ["compare-0"] }
}
}'
# Step 2: Upload each file to its task's upload_url (in parallel)
# PUT original.pdf → tasks[upload-original].upload_url
# PUT revised.pdf → tasks[upload-revised].upload_url
# Step 3: Poll GET /v1/jobs/:id?include=tasks until finishedThe compare_pdfs operation takes no extra options - just two input files in order: input[0] = original, input[1] = revised. Output is a single interleaved comparison PDF.
FAQ
Everything you need to know about comparing PDFs with SupaPDF.
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