Couryo blog
Email that lands and sells: turning visits into relationships, deliverability without the mystery, transactional email in practice and honest tool comparisons.
Email that sells10 min read
Ads bring the visit. Email brings the customer home: rented vs owned audience
Rented audience (social and ads) vs owned audience (your email list), with a worked example for your own numbers and how to start this week.
Read the articleDeliverability7 min read
DMARC p=none vs quarantine vs reject: a safe rollout
What p=none, p=quarantine and p=reject do, the sp, np, pct and t tags, how to read an aggregate report and when to move up without losing legitimate email.
Read the articleEmail that sells8 min read
Does email marketing still work in 2026? What the data says
Does email marketing still work in 2026? What the studies show (and what they don't), the common objections, and when email is not the right channel.
Read the articleHow-to7 min read
Email domain verification failed: how to fix it by DNS host
DKIM or SPF record not verifying? The 6 mistakes that block domain verification, how to spot each with dig, and the fix on Cloudflare, GoDaddy and more.
Read the articleAI agents8 min read
Email MCP server: how AI agents send and read email
What MCP is, the 3 kinds of email MCP server, how to connect one to Claude Code, Cursor and Codex safely, and the prompts that pay off most.
Read the articleDeliverability9 min read
Email provider suspended your account: what to do in the first 24 hours
Your email provider suspended your account? Why it happens, an hour-by-hour plan for the first 24 hours and how to keep it from happening again.
Read the articleDeliverability9 min read
Emails not reaching Outlook or Hotmail: the complete fix
Why your emails are not reaching Outlook and Hotmail, Microsoft's May 2025 sender rules (550 5.7.515), every common 5.7.x code and how to get unblocked.
Read the articleEmail that sells9 min read
SaaS onboarding email sequence: day 0, 1, 3 and 7
Build an event-triggered SaaS onboarding sequence: 5 emails with a goal and metric each, an exit when users activate, and the mistakes that cause spam.
Read the articleComparisons8 min read
SendGrid alternatives with a free tier (2026)
SendGrid replaced its free plan with a 60-day trial. Compare Resend, Postmark, Mailgun, Brevo, Mailtrap and Couryo, with verified pricing.
Read the articleHow-to9 min read
Supabase email rate limit exceeded: the fix
Getting email rate limit exceeded in Supabase Auth? The real limits, where to change them, how to set up custom SMTP and a production checklist.
Read the articleEmail that sells7 min read
Welcome email examples that work (and how to send them via API)
Five ready-to-copy welcome email examples (SaaS, store, course, app and B2B) with subject lines, preheaders and the code to send one at sign-up.
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