Infrastructure
Dedicated IP or shared pool: the volume and consistency test
22 October 2025 · 7 min read
A dedicated sending IP is often sold as an upgrade. It is better understood as taking ownership: your reputation stops being averaged with other senders, in both directions.
Two conditions decide whether that is an advantage — volume, and consistency.
The threshold test
Mailbox providers build IP reputation from observed volume. Below roughly 100,000 messages a month, and without a regular sending rhythm, a dedicated IP simply does not generate enough signal to earn a strong reputation — and idle gaps let what reputation exists decay.
| Monthly volume | Sending pattern | Recommendation |
|---|---|---|
| Under 100,000 | Any | Shared pool |
| 100,000–500,000 | Irregular or seasonal | Shared pool |
| 100,000–500,000 | Weekly or more often | Dedicated is viable |
| Over 500,000 | Regular | Dedicated, plus stream separation |
What each option actually gives you
- Shared pool: reputation established by aggregate volume, tolerant of irregular sending, insulated from your own occasional bad send — and exposed to other senders' mistakes.
- Dedicated IP: full control and full accountability, clean attribution in provider tooling, and a mandatory warmup period before it carries real volume.
Domain reputation now matters more than IP reputation
Major providers weight domain reputation heavily, which is why authentication and alignment have become the centre of deliverability work. A dedicated IP does not compensate for a poorly authenticated domain, a dirty list or a high complaint rate — it isolates those problems to you.
Fix authentication, hygiene and engagement first. The IP decision is an infrastructure refinement, not a remedy.
Key takeaways
- Below about 100,000 messages a month, a shared pool is the better choice.
- A dedicated IP requires consistent sending, not just high peaks.
- A new dedicated IP must be warmed before it carries volume.
- Domain reputation and list quality outweigh the IP decision.
Sources
Put this into practice with HTsend
Everything in this guide is built into the platform: authenticate a sending domain, clean your list before you send, and watch inbox placement in real time.
