Cold email glossary
Email deliverability
Email deliverability is the ability of your emails to reach the recipient's inbox rather than being filtered to spam or rejected. It is determined mainly by sender reputation, authentication, and engagement signals.
What is email deliverability?
Deliverability is different from delivery. An email is delivered when the receiving server accepts it, but it is only deliverable in the useful sense when it lands in the primary inbox where a human will see it. Mailbox providers like Gmail and Outlook decide that placement using hundreds of signals about the sender and the message.
The biggest inputs are sender reputation (the track record of your sending domain and IP), authentication (SPF, DKIM, and DMARC records that prove you are who you claim to be), list quality (bounce and spam-trap rates reveal how the list was built), and engagement (replies and reads help, deletes and spam reports hurt).
Deliverability is not a one-time setup. Reputation moves with every send, which is why sustained cold email programs treat it as something to monitor continuously rather than configure once.
Why it matters in cold email
In cold email, deliverability is the multiplier on everything else. The sharpest targeting and copy are worth nothing if the message lands in spam, and a damaged domain reputation can take weeks to recover. It is also why outreach should never run from your primary company domain: a deliverability problem on the domain your invoices and product emails use is a business problem, not a marketing one.
How Sendful handles it
Sendful sends from dedicated domains we register, authenticate, and warm for each client, and automated health checks watch reputation, bounces, and placement continuously so volume adjusts before problems compound. Your primary domain is never used for outreach.
What is a good deliverability rate for cold email?
Healthy programs aim to keep bounces under 2 to 3 percent and to land the large majority of sends in the inbox. Exact inbox placement is hard to measure directly, so practitioners watch proxies: bounce rate, spam complaints, reply rate trends, and seed-list placement tests.
How do I fix bad deliverability?
Stop sending from the affected domain, verify SPF, DKIM, and DMARC are correct, cut volume, clean the list of invalid and risky addresses, and rebuild reputation slowly with warmup. If the damage is severe, it is often faster to retire the domain and start fresh on a new dedicated one.
Does cold email hurt my domain reputation?
It can if you send from your primary domain or send to unverified lists. Run outreach from separate dedicated sending domains, keep lists verified, and ramp volume gradually so your main domain's reputation is never exposed.
How do I check my email deliverability?
There is no single perfect meter, so combine signals. Watch bounce rate and spam complaints, register your sending domains in Google Postmaster Tools for Gmail reputation, and run periodic seed or placement tests that sample where your mail lands across providers. Reply trends are the ground truth, since they only move when mail is actually being seen.
Go deeper
Cold Email Deliverability: The Complete Checklist
Every step that keeps cold email out of spam: domain setup, SPF, DKIM, DMARC, warmup, volume ramping, list hygiene, and the monitoring that catches problems early.
How to Set Up Google Postmaster Tools
How to set up Google Postmaster Tools, verify your domain, and read the spam rate, reputation, and authentication data that protects cold email deliverability.
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