Migration Mapping Validator
Check source-to-target identity mappings before a tenant migration. Find duplicate users, invalid UPNs, missing targets and domain inconsistencies without uploading the file.
Open the mapping file
Use a CSV or TSV containing a source identity and target identity column. The file stays in this browser.
Choose source and target
Validation result
What needs attention
Run validation to inspect the mapping.
Preview normalized mapping
Take the reviewed mapping forward
The validated export preserves the original columns. Only the selected source and target identities are normalized according to your options.
Designed as a migration preparation gate
Validate your identity mapping before bulk imports, domain cutover or migration batches depend on it.
The mapping file is parsed and validated in the browser. Opselith does not connect to your source or target tenant.
ShareGate and MigrationWiz presets can build on this validator later. This first version keeps the mapping contract generic and reviewable.
Validate Microsoft 365 migration mappings locally
Migration mapping problems are easier to fix before a migration tool or script consumes them. This validator checks source and target identities, duplicate mappings, formatting and domain patterns without uploading the file.
Useful before ShareGate, MigrationWiz or scripted migrations
Use the generic validated CSV as a clean preparation layer. Vendor-specific output formats and guided migration workflows can be added separately without changing the source mapping logic.
Keep working in Opselith.
Prepare migration inventory in PowerShell or clean the source CSV before validating it again.