If you are using Webhooks, Retention.com does not automatically cross-reference your existing contacts. You will need to manually upload your existing contacts so we don't identify or collect people you already have.
When to use this method
You are using Webhooks and
You are uploading your existing contacts for the first time on a new account
How to upload your existing contacts
The upload option is found inside your Webhook integration settings:
Log in to Retention.com
Go to Settings → Integrations
Open your Webhook integration
Find the Sync your existing contacts card
Upload your CSV file
Once uploaded, the file is sent to a processing queue. When complete, it will appear listed under the corresponding date in your Sync history.
File requirements
A header row is required
Put your email addresses in a single column — the header text itself does not have to be exactly
emailFile must be an Excel .CSV
Maximum file size: 500MB — split into smaller files if needed
Uploading MD5-hashed emails is not available in the self-serve webhook upload card — there is no "File contains MD5 encoded emails" option there. Upload plain text email addresses.
After uploading: Confirm the number of unique records in your Retention.com dashboard matches the count in your ESP.
How your data is handled
Uploaded contact lists are converted into encoded MD5 hashes for security. Retention.com does not use, share, or resell this data for any purpose other than preventing you from collecting and paying for contacts you already have.
What to do next