Deliverability best practices

What deliverability actually means

A delivery receipt tells you one thing: the message reached the recipient's thread. It does not tell you a person saw it, that the thread stays open, or that your line will still be landing messages next week.

Four different outcomes hide behind the word "delivered":

1. Queued. Accepted by the API.
2. Delivered. Landed in the recipient's thread.
3. Read. Opened by a human.
4. Replied. Someone answered.

Deliverability is your ability to keep reaching step 4, across hundreds of conversations, week after week, without a line going quiet. It is a rolling condition, not a per-message result.

curl -X POST https://api.bluereacher.com/v1/messages \
  -H "Authorization: Bearer brk_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "to": "+14155550187",
    "message": "Hey Dana, saw you opened the second location last month. Quick question about front desk staffing."
  }'

{
  "success": true,
  "message_id": "d_1788116691413_milvzs",
  "mode": "drip",
  "queued": true,
  "scheduled_for": "2026-08-31T09:14:51.413Z"
}

A queued send is an acceptance, not an outcome. Judge campaigns on replies. Treat everything before that as a leading indicator.

What you control, what the platform handles

Everything in the left column runs without you. Everything in the right column will sink a campaign if you get it wrong, and no amount of platform-side management compensates for a bad list or a reckless ramp.

Why sending patterns beat message content

Consumer messaging is judged on behavior before anyone reads a word. Three pattern signals carry most of the weight:

• Ramp. How fast volume climbs on a line that is new or has been quiet.
• Uniformity. How similar your sends look to each other in timing, length, and structure.
• Reaction. What recipients do: reply, ignore, block, report.

A well-written message sent 400 times in one hour from a three-day-old line will do worse than an average message sent 40 times across a day. Content still matters, but it matters through humans: better copy earns more replies, and replies are the strongest positive signal you can produce.

Pattern rules the platform enforces for you: randomized gaps between sends on a line, never a fixed interval; cold deliveries clamped to the recipient's local daytime; rotation across lines. Pattern rules that stay yours: vary the opening line across a batch (200 messages starting with the same six words is a pattern), keep the first message short, and hold links back until they reply.

Sustainable daily volume

The capacity model counts one thing: brand-new cold contacts per line per day. Contacts who ever replied are unlimited. Contacts you have messaged before are unlimited. Replies never count. The enforced numbers, the Blue Reacher policy caps of 50 opted-in / 30 fully cold new contacts per line per day on a warmed line, and the warm-up ramp that leads up to them, are in rate limits and sending capacity.

These thresholds track Apple's observed enforcement behavior, not an arbitrary product decision: iMessage spam detection watches new-contact velocity against account trust, and the caps hold every line inside the envelope a heavy human texter occupies. Limits scale with engagement; a line that consistently earns replies and near-zero spam reports gains headroom over time.

Scale with lines, not with volume per line. 200 opted-in conversations a day is four warmed lines at 50 each, never one line at 200. Pushing a single line past the safe range costs a cooldown, and in the worst case the number itself.

Reply rate is your health metric

Reply rate is the only number that reports both things at once: your messages landed, and they landed on people who wanted them.

Slice the number per line, per list source, and per day. A pool average of 9% can hide one line sitting at 1%. The comparison that isolates the cause: same copy, same list, two lines. If line A returns 11% and line B returns 3%, the line is the problem. If both fall together, the list or the offer is.

Track opt-outs as a share of replies too. Under 5% is normal. Above 10% means you are messaging people who never belonged on the list, and that feeds directly into line health.

List hygiene before a campaign

Do all of this before the first send, not after the reply rate disappoints.

1. Know the source and the date. Every number traces to a source and a collection date. Anything older than 90 days gets re-verified or dropped.
2. Normalize to E.164. +14155550187. Strip extensions, punctuation, and duplicated country codes.
3. Remove landlines and VoIP numbers. They cannot hold a thread and they distort every metric you will use to make decisions.
4. Dedupe across campaigns, not just inside this one. The same person contacted twice in 30 days from two different lists is your most likely report.
5. Apply your suppression list on every upload. Past opt-outs, current customers, open conversations, anyone who asked to be left alone. Every time.
6. Read 25 rows by hand. If you cannot say in one sentence why this specific person would care, the list is wrong. Pacing does not fix a wrong list.
7. Send a 50-contact test slice first. Wait 24 hours. Read the replies. Then scale.

Step 7 is the one operators skip and the one that saves lines.

Warning signs of degradation

Clean receipts with no replies is the most misread signal in outbound messaging. Delivered is not landed.

The recovery playbook

When a line degrades, run these in order.

1. Stop new outbound on that line immediately. Do not send a few more to confirm. More sends deepen the hole.
2. Keep answering live threads. Conversations already in progress are the healthiest traffic you have, and continuing them helps.
3. Isolate the variable. Two tests, 25 contacts each, 24 hours apart: the same copy on a known-good line, and the same list on a known-good line. One of them tells you whether the fault is the line, the list, or the copy.
4. Rest the line 72 hours minimum. No new conversations. Replies only.
5. Re-warm from day one numbers. 15 a day, then 30, then 50. Not from where you stopped. Full recovery takes 10 to 14 days and you cannot shorten it.
6. Fix the input that caused it. Rest treats the symptom. If you re-warm and go back to the same list at the same volume, you will be here again in two weeks.

If a line fails two re-warms, contact support and ask for a replacement. Two failures means the cause sits with the line, not with how you are sending.

Operating checklist

Daily. Compare reply rate per line against its own 7-day baseline. Clear the reply queue inside 4 business hours. Confirm no line went over its cap.

Weekly. Review opt-out rate by list source and retire any source above 3%. Rank lines side by side and flag the bottom one before it fails.

Per campaign. Run hygiene steps 1 through 7. Size the campaign to available line capacity before you upload, not after. Set the send window in recipient local time.

Reply speed belongs on this list. A reply that sits for six hours is worth far less than one answered in twenty minutes, to the deal and to the line.