put transactional and marketing email on different subdomains. mail.yourapp.com for resets and receipts, news.yourapp.com for the newsletter. when a campaign goes badly, you really don't want your password resets sharing its reputation.

SPF has a 10 DNS lookup limit and almost nobody counts them. add your CRM, helpdesk, newsletter tool, email API... each include pulls in its own includes. go past 10 and the whole record returns permerror. nobody warns you. mail just stops authenticating.

Are you light or night mode ?

Paddled out for waves, came back with a co-pilot 🐢 This tiny sea turtle hatchling hitched a ride on my board for a minute before heading back to the big blue. Best set of the day. #seaturtle #surfing #barceloneta

Has anyone had any luck getting Gmail to display the “Copy code” button? There’s an IETF draft (datatracker.ietf.org/doc/dra…), but I couldn’t get it to work.

if your DKIM key is still 1024-bit, it's time. gmail accepts 1024 but recommends 2048. while you're at it, set up rotation: publish a new selector, switch signing to it, keep the old one in DNS for a few days so mail in flight still verifies, then remove it.

p=none on DMARC doesn't protect anything. it just sends you reports. the way out: add rua=, read the aggregate reports for a few weeks, find every service sending as your domain, fix their alignment, then quarantine, then reject. most people either jump to reject and break their own invoices, or sit on none for years.

retrying a hard bounce doesn't get the email delivered. it just tells mailbox providers you don't clean your list. 5xx on a mailbox that doesn't exist: suppress, don't retry. 4xx: retry with backoff. bounce classification is a reputation feature, not a reporting one.

SES is cheap because you're the ops team. bounce and complaint processing, event pipelines, dashboards, alerting... it's all yours to build and run. great price per email. the real cost shows up in engineering hours.

New week and new flight from #Paris to #Roma this time, planning the in-flight backlog

check your PTR record. your sending IP should resolve to a hostname, and that hostname should resolve back to the same IP. gmail requires valid forward and reverse DNS from everyone sending to it. dig -x <your IP>, then dig the name you get back. two commands.

Don't be like Zuck: Linux penguin on the desk, Windows XP on the screen. Pick a side.

outlook.com joined gmail and yahoo: domains sending over 5,000 a day to outlook, hotmail and live addresses need SPF, DKIM and DMARC. non-compliant mail started landing in junk in May 2025, with outright rejection announced for later. there's no big provider left where you can skip DMARC.

something most devs don't know about gmail: send close to 5,000 messages in a day to personal gmail accounts once, and you're a bulk sender. permanently. the status doesn't expire. and every subdomain counts toward the same primary domain.

And here you go with mailkube's cli docs.mailkube.com/cli

a dedicated IP isn't an upgrade by default. its reputation comes only from your own traffic. a few thousand emails a week, sent irregularly, gives mailbox providers very little to go on. with steady volume and a proper warmup it's great. before that it's mostly a liability.