2 creditsCompare PDFs API — see exactly what changed
A page-by-page visual diff with a change ratio, a marked-up PDF showing where it changed, and the added and removed lines.
Compare PDFs aligns the two documents by page position and reports, for each page, a change ratio and whether it changed at all, plus the lines added and removed. It returns a marked-up copy of the new document with the changed regions highlighted, so you can see *where* a page changed rather than only that it did. Pages are compared as rendered images, which catches changes that a text diff misses entirely — a moved logo, a different signature block, an altered table rule. A small per-pixel tolerance means re-rendering identical content doesn't register as a change. Documents of different lengths are compared over their common pages, with the extra pages reported as added or removed; pages are matched by position, so an inserted page shifts the pages after it rather than being detected as an insertion.
How does the Compare PDFs API work?
One HTTP request from any language. Every ASHDOCS endpoint uses the same X-API-Key header.
curl -X POST 'https://api.ashdocs.com/api/v2/tools/pdf-compare' \
-H 'X-API-Key: ash_live_...' \
-F 'old=@v1.pdf' -F 'new=@v2.pdf' -F 'options={"include_text":true}'Common use cases
- →Checking what a counterparty altered in a returned contract
- →Verifying a regenerated document matches the previous run
- →Reviewing revisions between two versions of a report
Frequently asked questions
How much does the Compare PDFs API tool cost?+
2 credits per successful call. Sandbox keys (prefix ash_test_) run the tool end-to-end without ever consuming credits — use them in CI or for tuning.
What is the endpoint URL for this tool?+
The endpoint is documented in the curl example on this page. All ASHDOCS endpoints share the base URL https://www.ashdocs.com and require an X-API-Key header.
Can I run this tool inside Make, Zapier, or n8n?+
Yes — through each platform's built-in HTTP mechanism (Make's HTTP module, Webhooks by Zapier, n8n's HTTP Request node). Nothing to install: point it at this exact endpoint with your X-API-Key header. See /integrations/make, /integrations/zapier or /integrations/n8n for step-by-step setup.
Does this tool support batch or scheduled runs?+
Yes. POST /api/v1/batch runs any tool over up to 50 files with a single credit ledger entry, and pipeline schedules let you trigger the same tool on a cron. Both are documented in /docs.