How does throttling prevent IP reputation loss?

Throttling controls how fast you send email, preventing volume spikes that damage reputation or trigger blocks.

Preventing rate limit blocks: Mailbox providers limit how many messages they accept from any IP per hour. Exceeding these limits results in temporary blocks (4xx errors) or permanent rejection. Throttling keeps you within acceptable bounds.

Protecting new IPs: During warming, throttling ensures you don't send more than the IP's nascent reputation can support. Sudden volume on a cold IP looks like spam; gradual increases look like legitimate growth.

Responding to signals: Smart throttling systems monitor feedback. When bounce rates rise or deferrals increase, they automatically slow down. This prevents compounding problems by continuing to send into resistance.

Respecting recipient infrastructure: Smaller domains can't handle thousands of simultaneous connections. Throttling prevents overwhelming their servers, which would result in blocks and complaints.

ESPs implement throttling automatically. For self-hosted MTAs, configure settings like smtp_destination_rate_delay (Postfix) or use tools that monitor delivery feedback and adjust sending speed dynamically.

Throttling is the difference between a measured tide and a flash flood. Both deliver water, but only one doesn't cause damage.