Email Throttling

What It Is

Email throttling is the practice of intentionally limiting your sending velocity (per mailbox, per domain, or per campaign) so you don’t create sudden reputation shocks.

It’s not “send less forever”. It’s “send at a pace your infrastructure can sustain”.

Why It Matters

Two things can be true at the same time:

• Your targeting and messaging are solid
• Your results still collapse because you scaled volume too fast

Throttling protects:

• Reputation (your domains and IPs build a consistent history)
• Inbox placement (Inbox placement)
• Stability (reply rate doesn’t swing wildly week to week)

What Throttling Looks Like In Practice

Common throttling controls:

• Daily caps per mailbox (ex: 20-40 cold emails/day)
• Ramp schedules for new domains (increase weekly, not daily)
• Per-campaign caps so one sequence can’t burn your entire sending pool
• Pause rules when negative signals appear

Negative signals worth pausing for:

• bounce rate spikes (Bounce rate)
• inbox placement drops
• reply rate drops sharply across multiple segments

Throttling vs Warmup

Warmup is a one-time hygiene step. Throttling is an ongoing operating rule.

Related: Warm-up

The Minimum Viable Throttling Policy (MVP)

If you want a simple starting point:

1. Authenticate domains correctly (SPF/DKIM/DMARC)
2. Keep sends steady (avoid spikes)
3. Increase volume only when reply rate is stable
4. Pause on negative signals

For the bigger system (domains, routing, tracking, monitoring), see: Cold email deliverability and Outbound infrastructure.