Koltrix
Guides
Migrating Away From Fastmail or Proton Mail: A Practical Checklist
A checklist for moving a custom domain off Fastmail or Proton Mail: exporting mail, recreating aliases, switching DNS, and the extra steps encryption adds.
5 min read
Customer supportSaying no to a customer by email without losing them
How to turn down a feature request, an out-of-policy refund or a custom contract term by email, with worked examples and the mistakes that make a no sting.
5 min read
DeliverabilityCustom tracking domains and why shared link domains hurt
Click tracking rewrites links through a redirect domain. If that domain is shared, its reputation becomes yours. Set up a branded one with HTTPS.
4 min read
StartupsFounder-Led Sales Follow-Ups: A Simple Email Cadence
After the demo, the follow-up decides the deal. A four-email cadence for founders doing their own sales, with templates and a rule for when to stop.
4 min read
AI & emailThe limits of AI email sorting: edge cases to expect
Six situations where AI email sorting predictably gets it wrong, why each one fools the model, and the small habits and rules that cover the gaps.
5 min read
DeliverabilityDomain reputation vs IP reputation: which is hurting you?
Modern filters weigh your domain more heavily than your IP, but both matter. How to tell which one is dragging placement down and what fixes each.
4 min read
ProductWhat Happens During and After a Koltrix Trial
Seven days, no card, two seats. What a Koltrix trial includes, what to test while it runs, and exactly what happens to your mail and data when it ends.
5 min read
Team inboxOnboarding a new teammate to the team inbox in one week
A day-by-day plan for bringing a new hire into your shared inbox: reading history, drafting with review, owning one category, and a first solo shift.
4 min read
Email APIPer-provider throttling: pacing mail to big mailbox providers
Gmail, Outlook and Yahoo each defer differently when you send too fast. Build per-destination queues and adaptive concurrency that respond to 4xx replies.
4 min read
StartupsSunsetting a Feature: The Email Sequence Customers Deserve
Removing a feature people use is a trust test. Who to email, when to send each message, what to say, and how to handle the angry replies that will arrive.
5 min read
AI & emailCombining rules with AI classification
Rules are predictable, AI handles fuzzy intent. A decision table for which inbox jobs belong to each, how to layer them, and what to do when they disagree.
4 min read
DeliverabilityFive deliverability metrics worth alerting on
Skip vanity numbers. Alert on deferral rate, hard bounce rate, complaint rate, authentication failures and delivery latency, with sensible thresholds.
5 min read