Check PDF syntax

Check a PDF's structural health and get a clear verdict: valid, valid with warnings, or invalid.

PDFstructurecheck

Questions people ask

What can be wrong in a PDF's structure?: Common findings are a missing %PDF header or %%EOF terminator, a cross-reference table that needed rebuilding while opening, a trailer dictionary that cannot be found, object streams that fail to parse, and two readers disagreeing about the page count. Each finding is attributed to the checker that reported it, so you can judge its weight.
What does "valid with warnings" actually mean?: The document opened and its pages are readable, but at least one structural repair or complaint happened along the way: the file works, and the warnings tell you which corners are worn. Many tools would never mention them; we prefer you know.
Does the verdict promise the PDF will print or display right?: No, and any tool promising that from structure alone is overreaching. The verdict is about the file format's health: parsing, page access and internal consistency. Conformance profiles (PDF/A), accessibility and visual checks are different examinations, and this tool never claims them.
What do I get as output?: Two artifacts: a readable report.txt with the verdict, counts and every finding listed, and findings.json with the same data in machine-readable form for pipelines and checklists.
What about encrypted PDFs?: Refused with a clear message. A structural verdict of encrypted bytes would be a guess, so the tool declines rather than pretending to inspect what it cannot read.
What happens to my files?: The upload is removed as soon as processing finishes; the reports stay downloadable for about 10 minutes, then they are deleted automatically.

About this tool

A validator that narrows its promise instead of inflating it. Two independent readers examine the same bytes and their findings are attributed, so "valid with warnings" is precisely described instead of vaguely comforting. Technical details: the checker runs qpdf's structural engine over the file (open-time recovery warnings plus a full syntax pass) and then a strict pypdf parse, adds raw byte checks for the header and terminator, and cross-checks the reported page counts. Findings are bounded and length-capped, reader-internal names are scrubbed from checker messages, and the verdict is derived from the findings (errors mean invalid; warnings mean valid-with-warnings). The output report states the tool's scope: no conformance, accessibility, signature or rendering claim is ever made.

File limits

Exactly 1 file per job
Each at most 10 MiB
Result at most 10 MiB

Supported formats

PDF

Capabilities

PDFstructurecheck

Privacy & processing

Your file is processed in an isolated job on Tooley's own infrastructure. No third-party services are involved and nothing is stored beyond the result window.

Uploads are removed as soon as processing finishes. Results stay available for about 10 minutes, then they are deleted automatically.