Why two weeks is the floor, not the finish line

Two weeks is a commonly recommended starting period for a fresh domain. It gives mailbox providers time to observe a measured sending pattern and gives operators an initial set of delivery signals. The mistake is treating that date as permission to move immediately to full campaign volume.

What two weeks establishes

After two weeks of measured warm-up, a domain has some delivery history and an early record with mailbox providers. It still has limited experience handling sustained campaign traffic.

Campaign sending can begin carefully, but warm-up should continue. The campaign ramp and the warm-up process should operate together while the domain establishes a stable history at higher volume.

Warm-up should remain active after campaign sending begins. Increase campaign volume gradually as the domain demonstrates stable performance.

Increase volume in controlled steps

• Add campaign volume in increments instead of making a large jump.
• Hold each level long enough to evaluate bounces, complaints, and provider responses.
• Keep inbox density low so problems on one domain have a limited effect on the rest of the pool.
• Slow or bench a domain when its signals deteriorate instead of forcing additional volume through it.

Judge readiness by observed performance

A fixed number of days cannot determine how a domain will respond to campaign traffic. Domain age, list quality, message quality, density, and volume all affect the result.

Mailrun keeps warm-up running while campaign volume increases gradually. The goal is to establish consistent sending behavior without placing unnecessary pressure on a young domain.