Skip to content
SourcrLab

Knowledge Base

ATS Migration Checklist: 30 Steps for Switching Recruitment Systems

An ATS migration is not a database copy. It is a controlled redesign of data, workflow and ownership. The expensive failures usually happen because teams focus on the new interface and underestimate legacy-data quality, integrations, attachments, activity history, reporting and the exit terms of the old vendor.

Reviewed 23 August 2026·15 min read·Methodology
1992-style editorial recruitment technology illustration with a unique decision metaphor

SourcrLab verdict

Do not cancel the old system until the new system has passed a real workflow test and you have a verified, usable copy of the data you may need later.

Start with

Data and workflow audit

Biggest hidden risk

Incomplete activity/attachment/history migration

Cutover rule

Have rollback and ownership defined before go-live

Atlas-specific question

How will call/context history and agency data be mapped?

Download the ATS migration checklist (CSV)

Ungated. Assign an owner and status to every migration step before the project begins.

Download CSV

Atlas in this decision

Migrating to or from Atlas changes the data conversation

Atlas emphasises automatic call and client-context capture. For an agency, that means migration scope should not stop at candidate and job fields. Buyers should verify how notes, call context, client history, attachments, messaging and integration-derived data are imported, retained and later exported. The same principle applies to every platform: migrate the operational memory, not only the contact table.

Atlas research page

Phase 1: Scope the migration before choosing a go-live date

  1. 1Name one migration owner with authority to resolve data and workflow decisions.
  2. 2Define which entities move: candidates, contacts, clients, jobs, submissions, placements, notes, activities, attachments, consent records and custom objects.
  3. 3List every integration connected to the old system.
  4. 4Map every report or downstream process that depends on ATS data.
  5. 5Decide how much historical data must remain operational versus archived.

Phase 2: Audit and clean legacy data

Migration is a rare chance to remove years of taxonomy debt. Recreating every broken status, free-text field and duplicate record in the new system preserves the very problem the project is supposed to fix.

  • Measure duplicate candidate and contact records.
  • Identify fields nobody uses and custom fields whose meaning has drifted.
  • Find invalid emails, missing ownership and orphaned records.
  • Review retention, consent and deletion obligations before copying old data forward.
  • Decide which status values should be normalised instead of recreated one-for-one.
  • Sample attachments and activity history rather than assuming exports contain them.

Phase 3: Secure a complete export from the old vendor

  • Request a test export before the final migration window.
  • Confirm data format, encoding and stable identifiers.
  • Verify notes, emails, call logs, activity history and attachments separately.
  • Export configuration metadata or screenshots for workflows, templates and reports you may need to reproduce.
  • Store an immutable archive copy under your own control.
  • Document what the old vendor cannot or will not export.

Ask this before cancelling the old ATS

If we leave tomorrow, can you give us every candidate, client/contact, job, note, activity, attachment, custom field and consent record in a documented format that another system can ingest? Ask for a sample, not a promise.

Phase 4: Map the old data model to the new one

Atlas is a useful example here because its agency proposition includes richer relationship context than a minimal ATS. If you migrate into Atlas, verify how legacy call notes and client history map into the new context model. If you later leave Atlas, verify how that automatically captured context can be exported in a usable form.

Legacy objectMigration decision
CandidateStable ID, ownership, status, source, consent, tags and duplicates
Client/contactCompany hierarchy, owner, relationship history and permissions
Job/requisitionOpen/closed rules, stages, hiring team and historical reporting
ActivitiesNotes, calls, emails, meetings and timestamps
AttachmentsCVs, contracts, scorecards, search reports and file links
Custom fieldsKeep, rename, merge or retire

Phase 5: Rebuild integrations deliberately

  • Do not reconnect every legacy integration automatically; confirm it is still needed.
  • Revalidate calendar, email, job boards, sourcing tools, assessments, e-signature and BI connections.
  • Confirm field mappings and ownership when data flows both directions.
  • Test failure handling: logging, retries, alerts and operational ownership.
  • For agency stacks, include telephony, WhatsApp/business messaging and contractor-finance integrations where relevant.

Phase 6: Test with real workflows and representative data

  1. 1Load a representative data subset including clean and messy records.
  2. 2Run recruiter, hiring-manager and admin workflows end to end.
  3. 3Compare record counts and sample histories against the old system.
  4. 4Validate reports against known historical numbers.
  5. 5Test permissions with real user-role combinations.
  6. 6Run a migration rehearsal and measure how long cutover actually takes.

Phase 7: Plan parallel run, training, cutover and rollback

  • Define a data freeze or delta-sync approach so records do not diverge during cutover.
  • Keep the old system accessible long enough to resolve exceptions.
  • Train users on the new workflow, not only on menu navigation.
  • Publish one source of truth for go-live support and known issues.
  • Define the rollback condition before launch, including who can trigger it.
  • Only terminate the old contract once archive, data validation and operational sign-off are complete.

Phase 8: Audit the new system 30 and 90 days after go-live

  • Check adoption and workarounds: where are spreadsheets or shadow systems returning?
  • Review data-quality metrics and duplicate creation.
  • Compare expected versus actual integration reliability.
  • Review reports and fields that nobody uses.
  • Capture configuration changes before local workarounds become permanent architecture.
  • Document the exit/export process while implementation knowledge is still fresh.

Frequently asked questions

How long does an ATS migration take?

It depends heavily on data volume, cleanliness, integrations and change management. A simple small-team move can be fast; an enterprise or agency migration with historical CRM activity, custom objects and integrations can take materially longer.

Should all historical ATS data be migrated?

Not automatically. Separate operationally useful history from data that should be archived or deleted. Privacy, retention, reporting and future search needs should determine the scope.

What should we ask Atlas during migration planning?

For an agency, verify candidate/client records, notes, call/context history, attachments, integrations and the export path. Atlas offers a different relationship-data model from a basic employer ATS, so field-for-field migration assumptions are risky.

When can we cancel the old ATS?

After the new system has passed workflow and data validation, the archive is secured, integrations are stable enough for operations and the rollback window has closed by explicit decision.

Next decision

Need a shortlist rather than another generic list?

Use SourcrLab's decision flow to narrow the market around your team, workflow and constraints.

Help me choose

Related SourcrLab guides

Written by Pieter Henderyckx, a working recruiter

This guide is compiled from vendor documentation, public pricing pages and the catalogue's own evidence records, and ordered by how well each tool answers the question at the top of the page. Where a tool has been used in real recruitment work, its own page says so and who used it. Vendors cannot pay for a place in this list.