You can write the perfect email and still never be seen, because a spam filter decided before a human ever looked. Deliverability is the unglamorous foundation under every cold campaign, and it's where most outbound quietly dies. Here's what actually determines whether you land in the inbox.
1. Authentication: prove you are who you say
SPF, DKIM, and DMARC are the DNS records that tell receiving servers your mail is legitimately from your domain. Without all three aligned, modern providers throttle or bin you on sight. This is table stakes, and it's step one on any domain Lead Loop sends from.
2. Sender reputation: earn it slowly
Every sending domain and IP carries a reputation score built from how recipients react — opens, replies, spam complaints, bounces. A brand-new domain blasting hundreds of cold emails looks exactly like a spammer. Reputation is earned with time and restraint, which is why warmup and throttling exist.
3. List hygiene: never mail a bad address
Nothing torches reputation faster than bounces and spam traps. That's why verification isn't optional: every address MX-checked, catch-alls flagged, guessed addresses never sent. A clean, published-only list is a deliverability strategy, not just a data one.
4. Volume discipline: ramp, don't blast
Sudden spikes read as abuse. A daily send throttle — raised gradually as reputation builds — keeps you under the radar of the filters. More is not better; steady is better.
5. A real opt-out and a real address
A one-click unsubscribe and a genuine physical mailing address aren't just legal requirements — they're trust signals filters reward. Honor every opt-out instantly and globally, and complaints stay low.
How Lead Loop protects the inbox
Lead Loop sends from a dedicated warmed domain with full authentication, mails only verified published addresses, throttles and raises volume gradually, and honors opt-outs everywhere at once. Deliverability is built into the machine, not bolted on after the bounces start.