How email reputation works
For every message, Gmail, Outlook and other mailbox providers decide: inbox, spam folder or rejection. Here is what they look at, and what eesier does to protect your reputation.
Email reputation is the trust each mailbox provider (Gmail, Outlook, Yahoo) places in the domain and server sending a message. It is built through authentication (SPF, DKIM and DMARC), volume that grows gradually, few bounces, few spam complaints and recipients who engage.
What is email reputation and why does it decide delivery?
Email reputation is the history each mailbox provider keeps about a sender: the sending domain and the server's IP address. Based on it, Gmail, Outlook and Yahoo decide whether a message lands in the inbox, goes to spam or is rejected. Each provider forms its own opinion, independently of the others.
Deliverability is the share of email that reaches the inbox, not just the share that was sent. A message accepted by the recipient's server can still land in spam.
Providers mainly look at sender authentication, sending volume and pace, bounces (addresses that do not exist), complaints ("report spam") and how recipients react. A domain can have an excellent reputation at Gmail and still be unknown to Outlook.
What are SPF, DKIM and DMARC?
They are the three DNS records that prove an email really came from who it claims to come from. SPF lists the servers allowed to send for a domain, DKIM signs every message with a cryptographic key, and DMARC tells the provider what to do with a message that fails those checks.
Gmail and Yahoo have required all three from bulk senders since 2024, and Microsoft began requiring the same for Outlook.com in 2025.
At eesier, every sending domain has its own DKIM key (2048-bit RSA), and messages leave signed by our own mail server. On the domains we set up, SPF is published with a hard fail (-all) and DMARC with a p=reject policy, which tells providers to reject any message that impersonates the domain. The server's reverse DNS points to the same name it uses to greet providers.
You can send from a subdomain dedicated to your business (such as yourcompany.eesiermail.com), which eesier creates and authenticates automatically, or from your own domain.
Why does warm-up exist and how does it work?
A domain with no history that suddenly sends a lot of email looks like spam. Warm-up raises volume gradually until the domain proves it sends legitimate mail. At eesier, warm-up is automatic and calculated separately for every recipient provider: the pace at Gmail does not depend on the pace at Outlook.
Every combination of sending domain and recipient provider has its own daily limit. It starts at 20 emails per day and reaches 3,200 around the ninth day. The same limit applies to each sender address, and the most restrictive one wins.
The limit is lifted only after at least 21 days, 5,000 sends to that provider in 30 days, bounces of 2% or less and complaints of 0.1% or less. When a provider asks to slow down, as Gmail does with code 4.7.28, the pace drops on its own and deferred messages return in the hours when that provider usually accepts best. When a provider rejects many messages in a row, sending to it pauses before things get worse.
Replies to people already talking to you are not held by the warm-up limit.
How do bounces, complaints and unsubscribes affect reputation?
A bounce is an email returned because the address does not exist; a complaint is a recipient clicking "report spam". They are the two strongest negative signals a provider sees. Continuing to send to people who do not exist or do not want your email is the fastest way to destroy a domain's reputation.
Gmail and Yahoo bulk-sender rules require a spam complaint rate below 0.3% and one-click unsubscribe (the List-Unsubscribe header), honored within two days.
At eesier, every message carries a unique return address, so each bounce is tied to the send that caused it. An address that does not exist or that complained never receives email from our server again: the check runs before every send. The system tells a nonexistent address apart from a temporary refusal, so real people are not removed by mistake.
We receive complaints directly from the Microsoft and Yahoo feedback loops. When a message carries the unsubscribe header, it is signed by DKIM so the provider can trust it. When bounces or complaints rise at a provider, the volume sent to it drops automatically.
Which engagement signals do mailbox providers watch?
Beyond bounces and complaints, providers watch what recipients do with a message: whether they open it, reply, move it out of spam, add the sender to their contacts or delete it unread. Replies are among the strongest positive signals, because they show a real conversation between two people.
That is why relevant messages, sent to people with a reason to receive them, deliver better than generic blasts to cold lists. Content that earns replies strengthens the domain for the next sends; content that earns complaints weakens all of them.
Why does eesier spread out the sends of a campaign?
Because sending a whole campaign at once from a domain that is still warming up would burn its reputation with the providers that matter most. eesier spreads the sends over hours or days, at the pace each provider accepts, so the whole campaign reaches the inbox, not just the first part of it.
If your dashboard says your email domain isn't fully warmed up yet and the sends are being spaced out, this is what is happening: the emails are queued and go out as each provider's limit frees up room. Spacing delays a send; it does not cancel it.
During warm-up, hourly volume is also capped at one sixth of that provider's daily limit, so no provider receives everything at once. Bursts concentrated on a single provider are exactly what trips spam filters.
What does eesier do to protect your reputation?
eesier sends through its own email infrastructure, which authenticates every domain, paces warm-up per provider, stops sending to bad addresses and keeps watching the server's reputation. With the dedicated subdomain there is nothing for you to configure: the care happens on every send, automatically.
- Self-hosted mail server with DKIM signing per domain, hard-fail SPF, DMARC
p=rejectand matching reverse DNS. - Dedicated sending subdomain for your business, created and authenticated automatically, or sending from your own domain.
- Automatic warm-up per provider, with daily and hourly limits that grow as reputation is confirmed.
- Automatic slowdown when a provider asks for it, and a pause when it rejects many messages in a row.
- Bounce and complaint tracking, permanently blocking nonexistent addresses and people who complained.
- Reputation monitoring: checking the IP against blocklists such as Spamhaus, reading providers' DMARC reports, and enrollment in Google Postmaster Tools and Microsoft SNDS.
Frequently Asked Questions
How long does it take to warm up a domain?
Will the spaced-out emails still be sent?
Can I send from my own domain?
What happens when someone marks my email as spam?
What are the Gmail and Yahoo bulk sender rules?
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