Fix Email Deliverability Before You Increase Outreach Volume
Reply rates drop. Someone in the pipeline review suggests the obvious fix: send more. It is the wrong instinct, and since February 2024 it has been the expensive kind of wrong.
That month Gmail began enforcing requirements that changed what happens to a sender who scales into trouble. Volume is no longer a lever you can pull independently of reputation. Pull it on a domain already under pressure and you accelerate the damage.
The rules that actually govern your inbox placement
Google’s email sender guidelines apply to anyone sending 5,000 or more messages a day to Gmail addresses. Three obligations sit at the centre.
Authenticate the mail. SPF or DKIM is the minimum; Google recommends all three of SPF, DKIM and DMARC. The domain in your From header must align with either the SPF or the DKIM domain, which is what passing DMARC alignment means in practice.
Keep the spam rate below 0.3%, measured in Postmaster Tools rather than in your sending platform. Google is explicit that this is a ceiling, not a target, and advises senders to stay at or below 0.1%. From June 2024, senders above 0.3% became ineligible for mitigation — meaning the usual appeals stop working.
Offer one-click unsubscribe on marketing and subscribed messages, with a visible unsubscribe link in the body. Google’s guidelines FAQ clarifies that transactional mail is excluded. When Gmail announced the changes, it framed them as closing the gap between what good senders already did and what everyone else got away with.
What the three DNS records actually do
Teams treat SPF, DKIM and DMARC as a compliance checkbox. They do different jobs, and the failure modes differ too.
SPF publishes which servers may send on your domain’s behalf. Two mistakes recur: a new sending tool never added to the record, and more than one SPF record on a single domain, which invalidates both.
DKIM signs each message cryptographically so a receiver can confirm nothing was altered in transit. It is also what separates your mail from someone spoofing your domain.
DMARC sits above both and tells receivers what to do when a message fails: monitor, quarantine, or reject. Start at monitoring. Read the aggregate reports for a few weeks, confirm your own legitimate mail is passing, then tighten. Publishing a reject policy before you know which of your systems send mail is how companies discover their invoicing platform was never authenticated.
Separate what you can afford to lose
Reputation attaches to domains. That single fact drives the rest of the architecture.
Cold outreach carries more complaint risk than any other mail a company sends. Running it from the primary corporate domain means a bad campaign degrades password resets, invoices and customer replies at the same time. Sending from a dedicated subdomain contains the blast radius.
Click-tracking domains deserve the same treatment and rarely get it. A shared tracking domain inherits the reputation of every other sender using it, and nobody on a sales team ever looks at it. Use a branded tracking domain and the problem disappears.
Measure for weeks, then scale in increments
Warming a domain patiently rather than scaling straight to capacity is something SalesAR emphasizes in its anti-spam work, and Google’s own thresholds explain the arithmetic. A spam rate is a ratio. Tripling volume on a list that already complains at 0.2% does not hold the rate steady; it puts more messages in front of people likely to hit report.
Three numbers are worth watching before any increase. Spam rate in Postmaster Tools, which is the only figure Google actually enforces against. Bounce rate, where most outbound teams work to an informal ceiling of a few percent — a convention rather than a published rule. And whether open rates hold steady across consecutive sends rather than sliding.
Watch them for three or four weeks without a spike, then raise volume in steps rather than in one move. A rate that climbs after an increase tells you something a single campaign never will.
The legal floor is lower than the deliverability floor
Compliance and inbox placement are separate problems, and clearing the first does not help with the second.
The FTC’s CAN-SPAM compliance guide requires commercial senders to honour opt-outs within 10 business days and prohibits selling or transferring the addresses of people who have opted out. Its most-missed provision concerns liability: both the company being promoted and the party sending the mail are responsible. Hiring an agency does not transfer the exposure.
Other jurisdictions set a higher floor. Canada’s anti-spam law and the EU’s consent regime under GDPR both start from opt-in rather than opt-out, which matters for any team emailing across borders.
None of this resembles growth hacking. It is closer to checking the oil — a quarterly review of DNS records, list hygiene and complaint rates, done while nothing is wrong. Teams that only look after deliverability collapses are reading the gauge after the engine has seized.
Observer Voice is the one stop site for National, International news, Sports, Editor’s Choice, Art/culture contents, Quotes and much more. We also cover historical contents. Historical contents includes World History, Indian History, and what happened today. The website also covers Entertainment across the India and World.
