Generate CRM test data with duplicates built in

Fictional contacts in your CRM’s import columns with the duplicates you choose.

Free up to 2,000 rows a file and 10 runs a day. Sign up for Dedupely to go further.

Generated HubSpot contacts with two duplicate pairs highlighted and a Group column naming which rows belong together and how each copy was disguised.

Test data that looks like the real mess

A sandbox full of tidy rows proves nothing. Real duplicates hide behind a second email or a reversed name or a missing field. A dedupe that passes on clean test data fails on Monday.

This tool seeds the duplicates the way people create them and can label the truth for scoring.

Then run the real thing on it

Import the file into a test portal. Point a duplicate search at it. Count what was found against the groups you seeded.

Dedupely finds the seeded duplicates in your sandbox and shows every merge in Merge History.

A sandbox scorecard: 45 seeded duplicate groups, 44 found, 1 missed, 0 false matches.

Use it from a script or an AI agent

Use in Claude

POST https://dedupe.ly/tools/api/test-data-generator
{ "rows": 500, "duplicateRate": 0.15, "shape": "hubspot", "labelGroups": true }

MCP  https://dedupe.ly/tools/mcp   (tool: generate_test_data)
Docs https://dedupe.ly/tools/api/openapi.json

OpenAPI document · API index · llms.txt