Prepare and clean the source data
Begin CRM data migration with an unchanged, access-controlled copy of every source. Inventory each CRM, spreadsheet, inbox export, form, archive and connected system, recording its owner, approximate volume, date range, export method, sensitive information and known quality problems. Remove confirmed duplicates, standardise field names, formats and allowed values, identify incomplete records and assign an owner to unresolved exceptions. Decide what should be migrated, archived or excluded before transformation begins. Cleaning data before a move should preserve the original identifiers and the basis for every merge or exclusion so decisions can be reviewed or reversed.
Map the CRM data structure
Document how source data will become contacts, companies or accounts, leads, deals or opportunities, pipelines and stages, activities, ownership records and custom fields. For each field, record its destination, format, allowed values, required status, transformation rule and accountable owner. Confirm which source is authoritative when spreadsheets and legacy systems disagree, and note which reports, automations or integrations depend on the mapped fields.
Spreadsheet to CRM migration
A spreadsheet to CRM migration should start by separating record types and assigning stable source identifiers. Clean the customer and pipeline sheets, map columns to CRM fields, translate old stages into the agreed pipeline, resolve owners and prepare related records in the order the destination requires. Run a small representative import first, review ordinary and difficult records, correct the repeatable transformation and then migrate controlled batches. This approach also answers how to migrate pipeline data from spreadsheets without treating every row as an isolated contact.
CRM migration via API
CRM migration via API is appropriate when volumes, relationships, attachments, update rules or repeatable transformations exceed what supported CSV and import tools can control. CSV tools are often simpler for a bounded, well-structured dataset. An API migration needs documented authentication, rate and payload limits, stable external identifiers, idempotent writes, error logging and controlled batches. Validate each batch in the destination rather than relying only on a successful response, and stop when error patterns or reconciliation checks exceed the agreed boundary.
Protect relationships between records
Contacts, companies, deals, activities, owners and pipelines carry meaning through their links. Import parent records first where required, retain a source-to-destination identifier map and connect dependent records only after the destination identifier is known. Check that deals remain attached to the correct company and contact, activities retain their responsible owner and pipeline data migration preserves each opportunity’s intended stage. Ambiguous relationships should remain visible as exceptions instead of being guessed.
Validate before and after migration
Before cutover, reconcile source record counts, duplicate checks, field mapping and relationship rules against a representative trial. Review sample records across ordinary, incomplete, duplicate and permission-restricted cases. After each import, inspect failed imports, compare pipeline totals and record counts by type, verify ownership and relationships, and confirm that workflows, integrations and reports use the intended fields. Post-migration verification should record remaining exceptions, responsible owners, recovery steps and sign-off rather than treating technical completion as proof that every record is correct.
Plan cutover, recovery and handover
Name the migration window, any source freeze, responsible people, final export, transformation run, destination import and communication steps. Define stop and rollback criteria before the window begins, and verify backups and recovery instructions in proportion to the risk. After validation, hand over the mapping and transformation record, exception register, archived-source location, administrative access and recovery path. Define ongoing identity, required-field, ownership and retention rules so future imports and integration changes follow the same controlled standard.
CRM migration checklist
Before migrating: inventory every source and owner; preserve an unchanged source copy; define authoritative records and exclusions; agree duplicate and identity rules; map fields, owners, relationships, pipelines and stages; choose CSV/import tools or an API route; prepare a representative trial; define validation totals, stop criteria, cutover and recovery; migrate controlled batches; review failed imports and sample records; reconcile counts, pipeline totals and relationships; verify permissions, workflows, integrations and reports; and hand over the mapping, exception register and post-migration checks.