Blog
Deliverability, transactional email, team inboxes and AI that helps without taking over. Written by people who run email for a living.
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Developers ignore marketing email but read messages that save them from outages. The emails a dev-tool startup should send, how to write them, and what to skip.
Koltrix Team5 min read
A runbook for the life of an AI app connected to your email: how OAuth grants work, a quarterly review, when to revoke, what revoking does, admin off switches.
5 min read
What Gmail and Yahoo require from senders of roughly 5,000 messages a day: SPF and DKIM, DMARC, alignment, one-click unsubscribe and spam rates.
4 min read
Koltrix asks for five DNS records: ownership, MX, SPF, DKIM and DMARC. What each one does, what its value looks like, and the order to publish them in.
5 min read
A playbook for handling vendor pitches in a shared inbox: a ten-second look, when to reply or decline, when to block, and keeping pitches out of customer mail.
4 min read
How long should a sender keep retrying a deferred message? Exponential backoff with jitter, sensible give-up windows and what to tell users meanwhile.
4 min read
Buying a small SaaS product means inheriting its domains, senders and lifecycle emails. A practical plan for taking over its email without breaking anything.
5 min read
How to give priority customers faster email support without neglecting everyone else: defining priority, labels, targets, named contacts and honest plan terms.
4 min read
Point your app at a local SMTP catcher during development to see every message without risking real delivery. Setup, workflow and what it cannot test.
4 min read
Postmark is a strong transactional email service. If it's missing something you need, the right alternative depends on what that is. A fair guide by use case.
4 min read
A daily routine for working email through Claude or ChatGPT once connected: summarize unread, find threads, apply labels, draft replies, then review and send.
4 min read
Verified Mark Certificates need a registered trademark; Common Mark Certificates do not. Compare requirements, mailbox support and cost factors.
5 min read
Marketplaces email two audiences about the same events. How to map messages for buyers and sellers, relay conversations, handle disputes and route replies.
5 min read
Koltrix