PostStack vs SendGrid: Modern Email API vs the Legacy Incumbent

SendGrid (now part of Twilio) was the default transactional email API from about 2012 until Resend showed up in 2022. It's still the legacy choice for big companies and any platform that ships a SendGrid integration as standard, but the v3 API shows its age and the pricing model has fine print. PostStack is the modern, EU-hosted alternative. I built it specifically for teams who looked at SendGrid in 2026 and concluded "no, surely not still." Here's where each one wins.

Pricing

SendGrid removed the perpetual free tier in 2024. New accounts now get a 60-day trial that drops to 100 emails per day after sender-identity verification. The first paid tier (Essentials) starts at $19.95/month for 50,000 emails; Pro starts at $89.95/month for 100,000.

• Free / trial: SendGrid 60-day trial (100/day), then paid only · PostStack perpetual 3,000/month
• 10,000/month: SendGrid $19.95 (Essentials, no smaller tier) · PostStack €5 — ~72% cheaper
• 50,000/month: SendGrid $19.95 · PostStack €15 — ~19% cheaper
• 100,000/month: SendGrid $89.95 · PostStack €30 — ~64% cheaper

SendGrid also charges separately for dedicated IPs, advanced stats, single sign-on, and email validation — they're add-ons on top of the plan price. PostStack ships dedicated IPs as a €25/mo add-on from Pro up, and SSO without a separate enterprise contract.

API design

SendGrid's v3 API uses JSON keys like personalizations and dynamic_template_data, inherited from the SMTP-to-JSON era. It works, but it feels like 2015. PostStack's API takes the cleaner { from, to, subject, html } shape that Resend popularised.

// SendGrid v3
await sgMail.send({
  to: 'user@example.com',
  from: 'hello@yourdomain.com',
  subject: 'Hello!',
  html: '<h1>Welcome!</h1>',
});

// PostStack
await poststack.emails.send({
  from: 'hello@yourdomain.com',
  to: 'user@example.com',
  subject: 'Hello!',
  html: '<h1>Welcome!</h1>',
});

Features PostStack ships that SendGrid doesn't

• IMAP/POP3 mailboxes — Dovecot mailboxes for verified domains. SendGrid is send-only.
• DMARC aggregate report parsing — incoming XML reports get charted in the dashboard. SendGrid leaves them as inbox attachments.
• Visual email builder included — block-based drag-and-drop in the dashboard. SendGrid's builder is part of the separate Marketing Campaigns product.
• Workflow automation in the base plan — multi-step sequences ship with PostStack. In SendGrid, automation lives in Marketing Campaigns.
• EU data residency — SendGrid is US-only infrastructure.

Where SendGrid is genuinely better

SendGrid's scale is real — they process billions of emails and have feedback loops with virtually every ISP on earth. If you're sending tens of millions of messages per month to a global audience, their infrastructure depth is hard to match. They also have a much larger ecosystem of third-party integrations and a longer track record with legacy enterprise platforms (Salesforce, HubSpot, the older CMS world).

Deliverability

Both services handle SPF, DKIM, and DMARC setup. SendGrid has a longer reputation history and dedicated IP pools. PostStack runs Rspamd pre-flight scoring to catch spam-triggering content before it leaves your account, plus per-domain deliverability dashboards. For most teams under 1M sends/month the difference is negligible; both deliver.

When to pick each

Pick SendGrid if you already use Twilio for SMS, you're on a legacy platform that only supports SendGrid out of the box, or your volume is high enough to justify an enterprise conversation.

Pick PostStack if you want a modern API, EU-hosted infrastructure, predictable pricing without per-feature add-ons, and built-in features like IMAP mailboxes and DMARC parsing.

Migrating from SendGrid

The SendGrid migration guide walks through replacing @sendgrid/mail with @poststack/sdkand remapping the API key shape. Start on the free plan to run them in parallel.