The same applicant lands in your pipeline twice. Now two recruiters screen them, the same person gets the same automated email twice, and your source report counts one person as two.
At worst, a recruiter calls a candidate back and reads out an email address the candidate never shared - pulled from an older profile created years ago. The candidate is confused and trust drops before the first real conversation.
Duplicate candidate detection is what stops that. 100Hires recognizes a returning or re-applying candidate by their email address or LinkedIn URL and keeps everything on one record: one person, one timeline, one set of numbers.
Duplicate detection in 100Hires vs a typical ATS
Most ATS platforms can merge candidates. The difference is whether it happens automatically, what it matches on, and how much history survives the merge. Those three things decide whether your database stays clean on its own or needs a recruiter to babysit it.
What is a duplicate candidate
A duplicate candidate is the same person stored as two or more separate records in your database.
It usually happens four ways: applying to multiple roles, re-applying months later, teammates adding the same person from separate imports, or the same profile arriving from several job boards at once - career site, Indeed, and a sourcing tool all in the same week.
A duplicate is a data problem, not a candidate behavior problem. The person usually has no idea they appear in your system twice.
Each copy carries only part of the story, so the full history gets split across cards.
How 100Hires detects duplicate candidates
100Hires matches on two deterministic signals: the candidate's email address and their LinkedIn URL. When a new application or import matches an existing person on either one, 100Hires treats them as the same record.
You turn this on in Settings > Company > Automation with the "Auto-merge duplicate applicants" option. The 100Hires Chrome extension also flags a candidate already in your database while you source.
Being honest about the limit: because 100Hires matches on email or LinkedIn rather than fuzzy name or phone, a candidate who applies with a brand-new email and no LinkedIn on file can still create a separate record.
That deterministic approach trades a little recall for precision, so you avoid the false merges that name-only matching produces. When you spot one of those edge cases, you merge the records by hand and keep the full history.
For the bigger picture of how 100Hires keeps one profile per person across every job, see candidate tracking software.