Sender Reputation

1. Positive engagement signals — opens, clicks, replies, read time — strengthen sender reputation. 2. Negative signals — spam complaints, bounces, blocklist hits, volume spikes — damage reputation. 3. Mailbox providers aggregate these signals into a sender reputation score. 4. The reputation score determines whether emails are placed in the inbox, spam folder, or blocked entirely.

How Sender Reputation Works

Each major mailbox provider maintains its own reputation score for your sending domain and IP addresses. These scores are not publicly visible as a single number, but tools like Google Postmaster Tools and Microsoft SNDS provide partial visibility.

Reputation is built from:

• Engagement signals — opens, clicks, replies, read time
• Spam complaints — recipients marking your email as spam
• Bounce rates — how many of your emails fail to deliver
• Sending volume and consistency — sudden spikes raise flags
• Email authentication — SPF, DKIM, DMARC compliance
• List quality — hitting spam traps or invalid addresses

Domain vs. IP Reputation

• Domain reputation is tied to your sending domain (e.g., yourbrand.com). It follows you across email service providers.
• IP reputation is tied to the IP address your email is sent from. Shared IPs carry shared risk; dedicated IPs give you full control.

Gmail weighs domain reputation most heavily. Other providers may weight IP reputation more.

1. Domain reputation is tied to the sending domain and follows the sender across email service providers. 2. IP reputation is tied to the sending IP address and can be shared across senders on the same infrastructure. 3. Gmail and most modern providers weight domain reputation most heavily. 4. IP reputation matters more for dedicated sending infrastructure and legacy filtering systems.

Why Sender Reputation Matters

Sender reputation is the single most influential factor in inbox placement. A strong reputation means your emails go to the inbox by default. A damaged reputation means even legitimate, wanted emails may land in spam.

Reputation takes time to build and can be damaged quickly by:

• A single campaign with high complaint rates
• Hitting a spam trap
• A sudden spike in sending volume without warmup

How InboxAlly Helps

InboxAlly strengthens sender reputation by generating consistent positive engagement signals through seed emails. This is especially valuable during email warmup when building initial reputation, and during reputation recovery after a setback.