How to Export, Clean and Import Candidate Data When You Switch Applicant Tracking Systems

Switching applicant tracking systems (ATS) is mostly a data problem. The new tool is only as useful as the candidate history you bring into it, and a messy export can bury good candidates under duplicates and broken emails. This checklist walks through a low-risk way to move candidate records, using free browser tools for each cleaning step.

Step 1: Decide what is worth moving

Not every record deserves a trip across. Before you export, decide on a cut-off. Many teams move open requisitions, active candidates and a talent pool of people they would genuinely contact again. Rejected applicants from several years ago are usually better left in an archive export that you store securely rather than import.

Also check your legal retention rules. Candidate data is personal data, and retention periods and consent requirements vary by country and employer. If you hire in more than one market, ask your legal or privacy lead what you may keep and for how long before you import anything.

Step 2: Export from the old system

Most applicant tracking systems can export candidates as CSV, and some also offer JSON or an API. Export more than you think you need: name, email, phone, source, job applied for, stage, applied date, tags, notes and links to résumés. Take a second export that lists the job requisitions themselves, so you can map candidates to jobs later.

Open the file and look at it before you touch it. Check the row count against what the old system shows, and keep an untouched copy. If you ever need to roll back, that copy is your safety net.

Step 3: Remove duplicates

Duplicates appear when a person applies to several jobs or is added by both a recruiter and a referral. Sort or paste the email column into a duplicate lines remover to see how many unique addresses you really have. If your export is in JSON, a JSON duplicate remover does the same job for repeated objects. Decide in advance which record wins when two differ, usually the most recently updated one.

Step 4: Validate the emails

An import will carry over typos such as a missing dot or a swapped domain. Run a sample, and ideally the whole list, through an email validator. If the export mixes emails into free-text notes, an email extractor can pull them out first. Flag invalid rows instead of deleting them silently, so a recruiter can fix a high-value candidate by hand.

Step 5: Convert the format if the new tool needs it

Some importers want CSV and others want JSON. A CSV to JSON converter and a JSON to CSV converter let you move between them in the browser. If your spreadsheet is messy and you are not sure of the structure, CSV and Excel to JSON with AI can help you see how the columns map. For a deeper look at the same cleaning approach on sales data, see the older guide on cleaning a lead list before a CRM import; the steps carry over to candidate lists.

Match your columns to the new tool's import template. Read the new vendor's import documentation for required fields, date formats and any file-size or row limits, because these differ by product.

Step 6: Test with a small batch

Import 20 to 50 records first. Check that names, emails, stages, sources and notes landed in the right fields, that dates did not flip between day-first and month-first formats, and that no candidate was emailed automatically. Switch off any automated candidate messages for the test, then turn them on only when you are confident.

Step 7: Cut over and keep the archive

Once the test passes, import the full set, then spot-check a few well-known candidates. Keep the original export in secure storage for the retention period you decided in step 1, and restrict who can open it.

Choosing the new system

If you are still picking a tool, the ProductListo comparison Best Applicant Tracking Systems for Startups (2026) looks at published pricing, trials and AI screening for five options. You can read the individual profiles for Workable, Ashby, Greenhouse and Lever, or browse the wider CRM and sales guide if you also run a sales pipeline. Makers of recruiting software can submit a tool to the ProductListo directory or read about sponsored placements on the write for us page.

Quick checklist

• Set a cut-off and check retention rules.
• Export candidates and requisitions; keep an untouched copy.
• Remove duplicate records and decide which version wins.
• Validate emails and flag bad rows for review.
• Convert to the format the new tool needs.
• Test a small batch with automated messages off.
• Import in full, spot-check, and archive the original securely.