Koltrix
Startups
How to Announce a Price Increase by Email
Raising prices without losing trust comes down to notice, clarity and choice. How to structure the email, what to offer current customers, and handling replies.
5 min read
GuidesHow to write a one-page support playbook
A fill-in-the-blanks template for a single-page support playbook: addresses, owners, hours, triage, escalation, refunds, tone, and the links people need.
5 min read
DeliverabilityGetting off a blocklist: a calm, step-by-step playbook
Before requesting removal from a blocklist, find and fix what got you listed. A sequenced playbook for confirming, remediating and delisting.
4 min read
Customer supportAfter-hours and weekend email coverage for small teams
Four ways to cover support email after hours and on weekends, a decision table by customer type, a definition of urgent, and ways to protect your team's rest.
4 min read
StartupsAnnual Renewal Reminders: A Timeline That Prevents Surprise Charges
Annual renewals that surprise customers become chargebacks and angry tickets. A 60, 30 and 7-day reminder timeline, what each email says, and why it pays off.
4 min read
Guidesdig commands every email engineer should know
The dig queries that answer most email questions: SPF, DKIM selectors, DMARC, MX, PTR, MTA-STS and BIMI, plus how to bypass caches when testing.
5 min read
AI & emailKeeping confidential email out of the AI loop
A checklist for keeping sensitive email away from AI tools: identify confidential categories, separate mailboxes, control connections and set a team policy.
4 min read
GuidesThe Minimal Email Stack for a Pre-Seed SaaS
Before product-market fit, your email setup should be small, cheap and reliable. The four pieces a pre-seed SaaS needs, and what to put off until later.
4 min read
DeliverabilityDMARCbis is now RFC 9989: what changes for your record
DMARC moved to the standards track as RFCs 9989, 9990 and 9991. Here is what changed: pct is gone, np and psd arrive, and a DNS tree walk replaces the PSL.
4 min read
StartupsPlan-Limit Emails: Prompting Upgrades Without Breaking Trust
Telling customers they're near a plan limit is a moment of trust. When to warn, what to show, what happens at 100%, and how to suggest an upgrade calmly.
4 min read
Team inboxInbox handoffs across time zones without dropped threads
A follow-the-sun playbook for small distributed teams: overlap windows, a handoff note format, which threads to pass or finish, and time-zone-aware SLAs.
4 min read
Email APISuppression lists: what to suppress and for how long
Hard bounces, complaints and unsubscribes each deserve different suppression rules. Design a suppression list, scopes and expiry that protect reputation.
5 min read