Blog
Deliverability, explained plainly.
The mechanics behind SPF, DKIM, DMARC, and the rest of what decides whether a message lands in the inbox or the junk folder — written for the person who has to actually fix it, not just be told it’s broken.
This is WarmHawk’s blog: short, specific explainers on email authentication and deliverability, each one grounded in a real mechanism (an RFC limit, a DNS lookup budget, an alignment rule) rather than generic advice. Start with whichever post matches what you’re currently stuck on.
September 29, 2026
DMARC p=none vs quarantine vs reject: which policy should you actually run?
p=none only watches. p=quarantine routes failures to spam. p=reject blocks them outright — and jumping straight there without reading your own rua reports first is how legitimate mail gets silently dropped.
September 29, 2026
How many domains do you need for cold email? The actual math
Domain count is a function of one number: how many cold emails you want to send per day, divided by what a single inbox can safely carry before it starts burning reputation.
September 29, 2026
Google Workspace vs Microsoft 365 for cold email (2026)
The two platforms converged on nearly identical per-mailbox pricing in 2026 — the real difference for cold email is a Microsoft-specific new-tenant block that has no self-service fix.
September 29, 2026
Instantly pricing in 2026: what you actually pay, plan by plan
Instantly's cheapest plan is $47/month with unlimited mailboxes and warmup built in — the number that actually varies is how fast a growing team's leads and volume push it into a $194-555/month bundle.
September 29, 2026
Self-hosted email warmup: how it actually works
Self-hosted warmup trades a vendor's shared network of strangers' mailboxes for infrastructure you control end to end — the ramp still takes weeks, but the reputation risk you're exposed to is only ever your own.
September 15, 2026
Email Warmup: The Complete Guide (2026)
Warmup is a sender-reputation mechanism, not a checkbox — a mailbox that skips it gets treated as suspicious by every receiver on day one, no matter how good the copy is.
September 15, 2026
Dedicated IP vs Shared Warmup Pool: The Reputation Risk Nobody Explains
A shared warmup pool means your domain's reputation is partly a function of strangers you've never met and can't audit — one of them gets flagged, and the whole pool's placement can suffer.
September 8, 2026
SPF's 10-lookup limit: why a valid-looking record can still silently fail
A record that resolves fine and lists the right senders can still fail every recipient check, because the failure happens during evaluation, not lookup — and nothing in your own DNS ever shows you the count.
September 5, 2026
SPF, DKIM, and DMARC: what each one actually checks
SPF checks the sending server. DKIM checks the message itself. DMARC checks whether the two agree — and only DMARC can tell a receiver what to do when they don’t.