About MailCostCalc & Email Infrastructure Economics
Why modern software engineering teams evaluate transactional email providers beyond headline vanity pricing.
⚡ The Paradigm Shift: React Email vs Legacy HTML
For over a decade, Twilio SendGrid served as the default standard for transactional email delivery. However, building emails for SendGrid historically meant wrestling with archaic table-based HTML, brittle templating languages, and disjointed WYSIWYG dashboards.
Resend revolutionized the developer ecosystem by introducing React Email—treating email templates as modular, type-safe React/TypeScript components. Developers write emails directly in their Git repositories using familiar JSX syntax, enabling automated linting, unit testing, and instant local previews without leaving VS Code.
🌐 The Dedicated IP Economics Dilemma
One of the most consequential pricing divergences between SendGrid and Resend lies in their handling of dedicated IP addresses:
SendGrid's Plan Gating: On SendGrid, you cannot simply add a dedicated IP to an Essentials plan ($19.95–$34.95/mo). You are forced to upgrade to the Pro plan ($89.95/month baseline), even if your volume is only 40,000 emails per month.
Resend's Modular Add-On: Resend allows users on any Pro plan ($20/mo+) to attach a dedicated IP for a flat $30/month fee. A team sending 50,000 emails pays just $50/mo on Resend with a dedicated IP, compared to $89.95/mo on SendGrid.
📊 Log Retention & Operational Observability
When customer onboarding emails bounce or password reset links fail, observability is paramount:
- Resend: Retains 30 days of full email payloads, delivery logs, opens, clicks, and bounce diagnostics across all Pro tiers.
- SendGrid: Restricts activity history to 3 days on Essentials plans, forcing teams to purchase external log archival add-ons or upgrade to expensive tiers to troubleshoot deliverability regressions.
🔒 Zero-Tracking Architecture
MailCostCalc executes 100% client-side in your web browser. No projected email volume, company budget parameters, or email architecture selections are collected, stored in databases, or sent to backend servers.