Merge two contact lists into one

Two files in and one deduped list out.

Use in Claude

List A

List B

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

Two lists of 640 and 512 rows merged into one list of 913 rows with the overlap removed, matched on Email.

Combine lists without the overlap

Two exports share half their contacts. Pasting them together doubles those people. Every send after that goes out twice.

This tool lines up the columns and keeps one row per contact.

Merge where the lists came from

The two lists came from two systems. Marketing has one copy and sales has another. The spreadsheet fix lasts until the next sync.

Dedupely merges the duplicates inside the CRM and keeps new ones from settling in.

A webinar import and a trade show import that both created Ellis Crosby, merged into one CRM record with both imports kept in Merge History.

Use it from a script or an AI agent

Use in Claude 
POST https://dedupe.ly/tools/api/list-merger
{ "csvA": "Email,Name\n...", "csvB": "Email,Phone\n...", "keyColumns": ["Email"] }

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

OpenAPI document · API index · llms.txt

More free tools

CSV dedupe

Name splitter

Email normalizer

List merger

Domain extractor

Company normalizer

Test data generator

Get started for free

20 free trial merges and as much free support as you need to get your duplicates under control.

"The data in our CRM is much cleaner thanks to this App. Easy to use and relatively inexpensive."
H Chitty

H Chitty

HubSpot User

HubSpot MarketplaceHubSpot Marketplace
"I do recommend! A++ Pretty easy to use. Adequate reporting. SUPERB CUSTOMER SUCCESS!"
Alina T

Alina T

Sales Operations Specialist, FieldBee

51–100 employees
"Great tool that works as promised. Great customer support - Nestor was super helpful onboarding."

R McNaught

HubSpot User

HubSpot MarketplaceHubSpot Marketplace
"It prioritizes merging while keeping key data. Highly recommended for anyone using Pipedrive integration."
John K

John K

Head of Marketing, David J Anderson School of Management

Pipedrive MarketplacePipedrive user
"The app worked great and helped me a lot with hundreds of duplicates in Pipedrive."
Samo J

Samo J

Founder & CSO, TapHome

Pipedrive MarketplacePipedrive user
"Superior deduping logic with excellent support - highly recommend for cleaning up messy HubSpot records."
M Weppner

M Weppner

"Dedupely was incredibly easy to set up, and the support team replied almost instantly each time I reached out. In just a few

Yuliya

Pipedrive User

Pipedrive MarketplacePipedrive Marketplace
"Incredibly effective at tackling massive duplicate data cleanup - exactly what we needed."

D Wright

HubSpot User

HubSpot MarketplaceHubSpot Marketplace
"The application works great and [...] their customer support was responsive and helped me get on the right track!"

Shawnee K

Salesforce User

Salesforce AppExchangeSalesforce AppExchange
"Worked as expected and Nestor at Customer support was extremely helpful walking me through some nightmare duplicate issues."

DiBlasio S

HubSpot User

HubSpot MarketplaceHubSpot Marketplace
"I was really pleased with Dedupely. It's highly configurable and works well when used manually or for automated deduping."

Laura R

Salesforce User

Salesforce AppExchangeSalesforce AppExchange
"It couldn't have been much easier to connect to HubSpot and run my first dedupe."

Emily K

Mercy Housing

HubSpot MarketplaceHubSpot user
"It did more than I expected. Support is great!"

Paweł S

Pipedrive User

Pipedrive MarketplacePipedrive Marketplace
"Dedupely helped us to quickly de-duplicate hundreds of records, with a level of transparency that gives you confidence..."

Grattan H

Pipedrive User

Pipedrive MarketplacePipedrive Marketplace
"Our customers want to achieve great results fast. Everybody at HubSpot already knows what Dedupely can do..."
Scott B

Scott B

VP Platform Ecosystem, HubSpot

"This tool made a week long project take a few hours. Definitely a go-to for deduplication processes."

Burchard J

HubSpot User

HubSpot MarketplaceHubSpot Marketplace
"It took away the huge headache we had of merging over 27,000 duplicate contacts."
Sean B

Sean B

Managing Director, Legal CPD

"Most of all, our team has been impressed by the way the Dedupely Customer Success team consistently goes above and beyond."

Isaac J

Salesforce User

Salesforce AppExchangeSalesforce AppExchange
"Great support. They are on top of things, and answer questions very quickly."

Larry D

Pipedrive User

Pipedrive MarketplacePipedrive Marketplace
"Works really well, support is A++++++"

Andy G

Pipedrive User

Pipedrive MarketplacePipedrive Marketplace
"We had 300k records in our CRM. Despite the large amount, Dedupely was perfect. The support was especially outstanding."
Simon W

Simon W

Tillhub

~50 employees
"Worked very simply and effectively and suited my budget [...] Very happy to recommend a good app and integration."
Allan R

Allan R

Co-founder & Managing Director, Target3D

11–50 employees
"Dedupely was huge in improving the quality of my CRM database. It saved me hours of manual merging."
Marco S

Marco S

Information Systems Manager, Efecte

~200 employees
"Fantastic time saver with great filters - auto and bulk merging made so much easier!"
A Team

A Team

HubSpot User

HubSpot MarketplaceHubSpot Marketplace
"It helped us clean up a giant mess of duplicates after migrating to HubSpot from our old CRM."

J Eddie

HubSpot User

HubSpot MarketplaceHubSpot Marketplace
"Perfect solution that delivers exactly as promised. Does exactly what we need it to. Great tool."

A Grogan-Crane

HubSpot User

HubSpot MarketplaceHubSpot Marketplace
"In a matter of maybe 30 minutes [...] Dedupely automatically took care of my dupes and merge needs. So happy I found it."

Wasmer D

HubSpot User

HubSpot MarketplaceHubSpot Marketplace

Running CRM cleanup for clients? See the Partner Program

Skip to content