The signed copy
An offer letter or employment contract goes out as a PDF and comes back signed. Usually nothing changed. Occasionally a start date, a notice period, a salary figure or a restrictive covenant did, and the signature on the altered version is what the company is now arguably bound by.
Edits are not always deliberate. A candidate may sign a version their own adviser marked up, or an older draft that was sitting in their inbox. Either way, HR needs to know before the record is closed, not when the notice period is being argued about two years later.
Why a quick read misses things
The person checking a returned contract has usually seen dozens that week, all from the same template. That familiarity makes small edits hard to see. "Three months' notice" and "one month's notice" look alike when you know what the sentence is supposed to say.
Comparing the returned copy against the issued version takes a few seconds and catches every textual change, including deletions, which are the hardest to notice by reading because there is nothing new on the page.
The check
Compare the issued version against the returned copy in the comparison tool. If the candidate signed digitally and sent back the same PDF with a signature added, the text layer is intact and the comparison is clean. If they printed it, signed it and scanned it, the returned copy needs an OCR text layer; most HR systems and office scanners apply one. A scan with no text layer is refused, because there is nothing to compare.
Expect a little OCR noise on scanned copies and no substantive changes. Any substantive change goes back to the candidate before the record is closed. Comparing scanned PDF documents explains how to tell OCR misreads from real edits.
Clauses to look at first
- Start date and probation period.
- Salary, bonus, and any figure written both in words and in numbers.
- Notice period, on both sides.
- Non-compete, non-solicitation and confidentiality clauses, including how long they last and where they apply.
- Place of work, hours and remote working terms.
- Annexes: the job description, benefits schedule and policy acknowledgements.
Figures written in words and numbers deserve particular care. "Ninety (90) days" can have one half edited and not the other, and that inconsistency is a dispute waiting to happen.
A worked example
Say an offer letter goes out with a 90-day notice period, a 12-month non-solicitation clause and a joining date of the 1st. It comes back signed with a cover email that says "all good, see you on the 1st".
The comparison returns two changes. On page 2, "ninety (90) days" became "thirty (30) days" in the notice clause. On page 3, the non-solicitation period went from 12 months to 6. Nothing else changed. Maybe the candidate's previous employer used shorter terms and they edited the clauses to match what they expected, maybe it was a draft from an earlier conversation. Either way, HR now raises it before day one instead of discovering it when the person resigns.
Policies and handbooks
The same comparison is useful on the company's own documents.
- Compare the new handbook against the current one before roll-out and publish the change list with it, so staff know what changed rather than being asked to re-read 60 pages.
- Compare a template update against the previous template to confirm only the intended clauses changed.
- Keep the redlined PDF with the policy version as the record of what was approved.
When legal sends back a revised template, comparing it against the version HR sent them is faster than asking for a list of edits, and it catches the ones nobody thought to mention.
When the comparison finds a change
Keep it factual and quick. Send the candidate the redlined PDF with a short note: these clauses differ from the offer we issued, can you confirm which version you intend to sign? Most people answer the same day, and most of the time the answer is that they signed the wrong file.
If the candidate wants the change, it becomes a negotiation, and the hiring manager and legal decide it like any other request. Either way, issue a clean final version, get it signed, and compare that one too before filing it. It takes seconds, and it means the copy on file is the one everyone agreed to.
Volume, privacy and cost
Documents up to 30 pages can be compared without an account, and files are processed in memory and never stored, which matters for documents carrying salaries and personal details. A free account allows five comparisons a month on documents up to 100 pages. Teams checking contracts every week usually move to the Business plan or connect their HR system to the API.
The HR industry page covers the wider workflow.
Try it on your own documents. Upload two versions on the homepage. Documents up to 30 pages need no account, and nothing is stored.
Industry page: PDF comparison for HR and employment documents