A suppression list is the record of every number you must not text, people who opted out, wrong numbers, and anyone flagged do-not-contact. It's one of the quietest and most important tools in a compliant program, because texting someone who's on it is a clean violation and a fast way to draw complaints. Here's what it is and why it matters.
What goes on a suppression list?
Every number that should never receive a message:
- Opt-outs, anyone who replied STOP or asked in any words to stop.
- Do-not-contact flags, numbers a campaign has marked off-limits for any reason.
- Invalid or wrong numbers, disconnected lines or reassigned numbers.
- Litigation or complaint risks, numbers flagged to avoid.
Once a number lands on the suppression list, it stays there, and no send goes to it.
Why is suppression a core compliance tool?
Because honoring opt-outs is one of the TCPA's central requirements, and the suppression list is how you actually do it. When someone opts out, they go on the list, and the list is checked before every send so they never hear from you again. It's the mechanism that turns "we honor opt-outs" from a claim into a guarantee. A campaign without a reliable suppression list will eventually re-text someone who opted out, which is exactly the violation plaintiffs look for.
Why does it have to work across every campaign?
Because a voter who opts out of one message opted out of you, not just that send. The suppression list has to apply across every campaign, list, and import that touches the same contact, or you'll re-add an opted-out number on the next upload and text them again. This is the failure that catches careless programs: they honor STOP on one campaign but re-import the number into another. A suppression list that spans everything is what prevents it, and it also protects deliverability by keeping complaint rates down.
Frequently asked questions
What is a suppression list?
A record of every number you must never text, opt-outs, do-not-contacts, and invalid numbers, checked before every send so those people never receive a message.
Why do you need a suppression list?
Because honoring opt-outs is a core TCPA requirement, and the suppression list is the mechanism that enforces it. Without one, you'll eventually re-text someone who opted out.
Does a suppression list work across campaigns?
It has to. An opt-out applies to you, not just one send, so the list must span every campaign and import, or a re-upload will re-add an opted-out number.
Keep reading: handling opt-outs the right way and why political texts get filtered. For the rules, see the FCC.