Warming Up a New Phone Number and Keeping it Healthy

Why warming up matters

A new number has no messaging reputation with the carriers yet, so the first few weeks of traffic decide how it gets treated. Carriers watch how people react to messages from each number. Replies are a good sign. Opt-outs, spam reports, and messages to dead or unengaged numbers are bad signs.

If a brand-new number starts with a large broadcast and a high share of people opt out or report it as spam, that pattern looks like spam and often leads to:

• Filtering: messages show as sent but never reach the phone.
• Throughput limits: the carrier slows how fast the number can send.
• Carrier intervention: the number gets flagged or blocked, and can be hard to recover.

Warming up is simply earning trust before asking for volume. 

Before you send your first message

A clean start beats a fast start. Check these before the number sends anything:

1. Your list has consent. Only text people who opted in to hear from you. Note when and how each lead opted in.
2. Your list is scrubbed. Remove opt-outs and anyone on Do Not Call or known-litigator lists.
3. Your first batch is chosen. Pick the small group of best leads you will start with (see below).

Ease into volume:

Start small and raise volume only while the number stays healthy. How fast you move depends on how people respond, not on a set schedule. For most numbers this takes days to a couple of weeks, not months.

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Two rules make the ramp work:

• Only move up when the current week looks good. If opt-outs or complaints rise, stay at the same level or step back.
• Spread sends across the day. A steady flow during normal business hours looks human. A burst of hundreds of messages in one minute does not.

Start with your best leads, and talk naturally

A new number's first conversations should be the ones most likely to go well. Use it only with high-intent leads who opted in recently. They expect to hear from you and they reply. They're also less likely to opt out or report spam when your first text mentions the request they made.

Save older leads, cold lists, and re-engagement campaigns until the number has a few weeks of clean history.

Early messages should read like a one-to-one text, not a blast:

• Use their name and context. Mention what they asked about or where they came from.
• Ask a question. Replies are the strongest positive signal you can earn.
• Keep it short and plain. Skip heavy links, all caps, and sales language in the first few weeks.
• Identify yourself. Say who you are, the name of your company, and how to opt out.

Build engagement history: what to watch

Carriers trust numbers with good reply rates, few opt-outs, and almost no complaints. Check these numbers for each new number daily in the Bonzo Deliverability Dashboard during the warm up period.

These ranges are intended as general guidelines. Use your dashboard statistics to evaluate performance at the phone number, campaign, and broadcast levels, comparing results across different time periods to identify trends and determine whether performance is improving or declining.

If a number enters the "Pause and Review" range, pause broadcasts and return to one-to-one messaging with your highest-quality leads. Review your contact lists and message content before gradually increasing volume again.

Once a number has established several weeks of consistent, healthy messaging activity, you can begin increasing its volume and expanding into broader campaigns while continuing to monitor performance.

Low delivery rates may indicate that carriers are filtering messages based on specific content. If your delivery rate falls below 85%, review and revise your message content, while also checking for other potential delivery issues, before resuming higher-volume messaging.

Keep the number healthy after warm-up

Warm-up builds a reputation, and everyday habits keep it. Carriers keep scoring every number, so a well-warmed number can still get filtered if its traffic slips.

• Keep volume steady. Avoid sudden jumps well above your normal daily volume. For a big send, build up to it over several days or split it across days.
• Keep your lists clean. Re-scrub on a regular schedule for opt-outs, Do Not Call, known litigators, and disconnected or reassigned numbers. The FTC requirement is to do this every 30 days. Lists go stale even if you never add to them.
• Send older leads in small batches. Re-engagement campaigns to cold leads carry the most risk. Send them in small groups and watch opt-outs before sending more.
• Reply quickly. When someone responds, answer in natural language. Conversations are the strongest signal that your messages are wanted.
• Respect quiet hours. Send between 8 a.m. and 9 p.m. in the recipient's time zone. Some states are stricter.
• Don't rotate numbers to dodge filters. Spreading the same blast across many numbers to avoid filtering is a red flag to carriers and can get all of them blocked.
• Re-warm idle numbers. A number that has been quiet for a few weeks should ease back into volume, not jump straight to full sends.

Keep checking the metrics in the table above every week, not just during warm-up. If a number slips into "slow down" or "pause and review," treat it like a new number: cut volume, go back to your best leads and one-to-one messages, and fix the list or content before ramping again.

Common mistakes to avoid

• Launching a big campaign on day one. This is the fastest way to get a new number filtered.
• Warming up with your worst leads. Old, cold, or purchased lists bring opt-outs and complaints that stick to the number.
• Sending the same message to everyone. Identical blasts look automated. Personalize, especially early.
• Swapping numbers to escape filtering. A new number fixes nothing if the list or content is the problem, and it starts the warm-up over.
• Jumping volume after a quiet stretch. A number that sat idle for weeks should ramp back up, not restart at full volume.