An SMS opt-out is the recipient's decision to stop hearing from you, and carriers require that it always works. dialnote watches every inbound message for the standard keywords, records the opt-out, and refuses any further texts to that number. There's nothing to switch on.
This guide covers which keywords are recognized, what changes once someone opts out, how they opt back in, and how do-not-call requests relate to Blocking Numbers.
Which keywords dialnote recognizes#
Matching is case-insensitive and exact. A message has to be the keyword on its own, so "stop by tomorrow at 4" doesn't opt anyone out.
| Keyword | What it does |
|---|---|
| STOP, STOPALL, UNSUBSCRIBE, CANCEL, END, QUIT | Opts the person out. Your organization can't text that number again. |
| START, UNSTOP, SUBSCRIBE, YES | Opts them back in and records fresh consent. |
| HELP, INFO | Sends instructions on how to opt out, opt back in, and get support. |
Keywords are processed before anything else touches the message. Your auto-replies and AI agents never see a STOP, so there's no way for a bot to answer one instead of honoring it.
What changes when someone opts out#
The opt-out is recorded against the number, for your whole organization, on the channel they used. It's not per teammate and not per phone number, so one STOP covers everyone on your team.
From then on, any attempt to text that number fails with "Recipient has opted out of messages". That includes messages your team sends by hand, canned responses, auto-replies, scheduled messages, and AI agent texts.
Two things carry on working:
- They can still reach you. An opt-out stops your outgoing texts. It doesn't stop them texting or calling in, and their messages keep landing in your inbox.
- Calling is unaffected. Opt-out keywords are an SMS rule, so nothing about a STOP blocks your team from dialing that number.
Who sends the confirmation
For SMS in the US and Canada, your carrier delivers the "you have been unsubscribed" reply at network level, so dialnote deliberately doesn't send a second one and your contact isn't texted twice. START and HELP replies come from dialnote.
How someone opts back in#
Only the contact can reverse their own opt-out, by texting one of the START keywords from the same number. dialnote clears the opt-out, records the new consent with its source, and confirms it to them.
There's no toggle in dialnote to opt someone back in on their behalf, and that's on purpose. Consent has to come from the person who withdrew it, and a switch that let a rep undo a STOP would be the fastest route to a complaint.
If a customer says they've fixed their end and still can't hear from you, ask them to text START to your number and watch for the confirmation.
Do-not-call requests for calls#
Opt-out keywords cover texting. There's no equivalent keyword for voice, so a "don't call me again" request needs a deliberate action from you.
Blocking the number is the way to hold your whole team to it. A block works in both directions: their calls and texts stop reaching you, and nobody in your organization can call or text them until someone unblocks. That makes it the closest thing dialnote has to a do-not-call entry, and it survives staff turnover in a way a note on a contact record doesn't.
To add one: Settings → Blocklist → Block a number, then add the reason so the entry explains itself later. Full walkthrough in Blocking Numbers.
Worth pairing with a contact tag such as "do not call", so anyone looking at the record sees the reason before they wonder why the number won't dial.
Opt-outs compared with blocking#
| Opt-out (STOP) | Block | |
|---|---|---|
| Who decides | The contact | You |
| Triggered by | Their text message | Your action in dialnote |
| Stops your outgoing texts | Yes | Yes |
| Stops your outgoing calls | No | Yes |
| Stops their incoming calls and texts | No | Yes |
| Who can undo it | Only the contact, by texting START | Anyone on your team, from Settings → Blocklist |
The two run independently. Blocking a number doesn't cancel an opt-out it already has, and a blocked number that texts STOP still gets its opt-out recorded, so unblocking them later doesn't accidentally put them back on your texting list.
What A2P registration expects from you#
US A2P registration checks your opt-out practice as part of the review:
- At least one sample message has to carry opt-out instructions, usually "Reply STOP to unsubscribe"
- Your campaign records the opt-out wording carriers send on your behalf, which defaults to "Reply STOP at any time"
- Your help wording defaults to "Reply HELP for support"
Keyword handling itself is already built in, so registration is about describing it accurately rather than building anything.
Never work around an opt-out
Texting an opted-out number from a second dialnote number, or asking a customer to opt back in on their behalf, is the kind of thing that gets a campaign shut down and a brand blocked by carriers. The gate exists to protect your delivery rates as much as the recipient.
Next steps#
- Blocking Numbers: stop a number reaching your team, in both directions
- A2P Brand & Campaign Registration: what US carriers require before you text
- SMS & MMS: sending, delivery status, and message limits
- Compliance overview: recording consent, regulatory bundles, and messaging rules
- Troubleshooting: work out why a message didn't send