Dedicated IPs

By default, live email leaves from IPs shared with other senders, whose reputation is kept high for everyone. With the Dedicated IPs add-on, your organization's live email leaves from IPs only it uses, so your deliverability depends on your sending alone. They are Amazon SES managed dedicated IPs: SES leases them, adds and removes IPs as your volume changes, and warms each one up per mailbox provider.

Dedicated IPs suit steady volume: SES assigns the first IP once you send a few hundred emails a day over a few days, and may hand it back if volume stays low (your email then leaves from shared IPs again, with nothing held back). Below that, shared IPs deliver better.

Turning them on

Add Dedicated IPs on the dashboard's billing page (owners; on the plans listed in Add-ons). Once the payment clears, COSS sets up your pool, usually within a couple of minutes, and live emails go through it from then on. Your organization needs at least one sending domain. Sandbox emails are never affected.

The add-on's monthly price is charged up front, prorated for the first month, and email sent through your dedicated IPs is also metered (see usage rates).

Transactional and marketing email

Both streams leave from your dedicated IPs, so all your live email builds the same IPs' reputation. Each stream still goes through its own sending configuration: coss.com measures their bounce and complaint rates apart, and pausing marketing email never stops your transactional email. Because they share the IPs, though, a marketing campaign that draws many complaints can hurt how mailbox providers treat your transactional email too: keep your lists clean.

Warm-up

New IPs have no reputation, and mailbox providers accept only a little mail from them at first. SES ramps each IP up per provider as it builds trust: while it does, what an IP can't take yet leaves from shared IPs, so warm-up never delays your email. The Dedicated IPs page in the dashboard shows how far along it is:

A pool can go back from ready to warming, for example when a sudden rise in volume makes SES add an IP. Read the same status from the API:

const { data: pool } = await coss.email.dedicatedIps.get();

console.log(pool?.status, pool?.dedicated_share);
for (const ip of pool?.ips ?? []) console.log(ip.ip, ip.delivered_7d);

Keeping a good reputation

A dedicated IP's reputation is yours alone, good or bad. Keep bounce and complaint rates low (the Reputation guard watches them either way), send to people who asked for your email, and change volume gradually. If one of your IPs is listed on a blocklist, ask that list for its removal: SES doesn't rotate managed IPs.

Removing them

Remove the add-on on the billing page: it ends with the billing month. Live email then goes back to shared IPs at once, and the pool is released a day later; adding it back before then keeps the same IPs.