About High-Volume Audiences

You can have as many contacts as you want in your Mailchimp audience. However, Mailchimp is a browser-based application, so there are a few things you should know when you have a large audience.

• Importing a very large audience into Mailchimp can take a while. If this is taking way too long, reach out to a developer to look into syncing your database with Mailchimp through the API.
• If you import an audience of more than a few hundred thousand contacts into Mailchimp, keep in mind that some audience pages may load slowly.
• If you try to perform a search across an audience of hundreds of thousands of contacts, it could be slow or unavailable.
• If you have an audience of more than 100,000 contacts, the sort feature using column headings in the contact table doesn’t work. Try exporting your audience as a CSV file then sort your contacts with an external spreadsheet program.
• In theory, Mailchimp can send millions of emails from our servers per hour, but no internet service provider (ISP) would accept that much email so quickly. ISPs throttle emails to prevent massive spam attacks from bringing down their services. We in turn throttle our delivery, based on each ISP. This results in slightly longer delivery times for very large audiences, but higher delivery rates.