Resend vs Postmark: Which Email API Should Developers Pick?

Resend is the newer, developer-first email API built around React Email and clean SDKs; Postmark is the established transactional specialist with a decade of deliverability data. Both are pleasant to integrate and both are priced for startups. The differences are in maturity, content policy, free tiers and what happens when you also need marketing mail or an inbox.

Quick answer

Pick Resend if you build in JavaScript or TypeScript, want to write emails as React components, and value a generous free tier for early development. Pick Postmark if deliverability track record, detailed logs and strict transactional hygiene are worth a small monthly fee. Neither gives you a mailbox. OquMail adds free inboxes and a simple send API on the same domain for small businesses that need both.

Feature comparison

• Mailboxes: neither provides inboxes; both are sending APIs
• Free plan: Resend offers a free tier with a monthly and daily cap suitable for development; Postmark offers a small monthly test allowance before a paid plan
• API: Resend has SDKs for Node, Python, Go, Ruby, PHP and more plus SMTP; Postmark has SDKs, SMTP and a templating system with layouts
• DNS guidance: both require DKIM and a Return-Path or bounce domain via CNAME, and both show verification status in the dashboard
• IMAP/SMTP: SMTP for sending only on both; no IMAP
• Storage: both keep event logs for a limited window; Postmark stores full message content for a set retention period on paid plans

Where Resend wins

• React Email lets front-end teams build templates in the same codebase
• Free tier is large enough to ship an MVP without a card
• Broadcasts product covers simple newsletters from the same account
• Modern dashboard and fast onboarding for solo developers

Where Postmark wins

• Long public track record on deliverability and time to inbox
• Message Streams keep transactional and broadcast reputations separate by design
• Searchable message content in logs, which support teams rely on
• Mature bounce handling, inbound processing and templates with layouts

Total cost at 5 and 15 users

Both charge by monthly email volume rather than team size. A small app on Resend can run free for a while; on Postmark it is a small fixed monthly plan. At tens of thousands of messages the two converge. Neither cost includes mailboxes for your 5 or 15 staff, so add a mail host to the real total.

The free third option: OquMail

OquMail is the option when a small company wants to stop thinking about vendors. The free plan gives 15 mailboxes on 3 domains, and the same dashboard issues Bearer API keys for a send endpoint with a four-field JSON body. It suits low-volume transactional mail and everyday inboxes on one domain; graduate to Resend or Postmark if volume or template needs outgrow it.

• Free plan: up to 15 mailboxes, 3 domains, 5 GB per mailbox, no credit card
• Webmail included; IMAP/SMTP for Outlook, Apple Mail, Thunderbird and phones
• IMAP mail.oqumail.com port 993 (SSL/TLS); SMTP mail.oqumail.com port 587 (STARTTLS)
• Guided SPF, DKIM and DMARC with live DNS verification; MX is mail.oqumail.com priority 10
• Transactional send API at https://api.oqumail.com/api/v1/emails with Bearer API keys (from, to, subject, html)
• Per-message delivery logs so you can see the exact response a receiving server gave

Verdict by scenario

• Next.js or React product with a small team: Resend
• SaaS where a missed password-reset email is a support incident: Postmark
• Small business site with order confirmations and a support inbox: OquMail
• Team sending both newsletters and receipts: Resend with Broadcasts, or Postmark with a Broadcast stream

Common questions

Does Resend support SMTP?

Yes. Resend exposes an SMTP relay alongside its API, useful for frameworks and tools that cannot make HTTP calls. Postmark also offers SMTP with per-stream tokens.

Can I send marketing email through Postmark?

Only on a Broadcast message stream. Transactional streams are policed and bulk marketing on them will get your account paused.

Why would I want an inbox with my email API?

Because customers reply. A receipt from orders@ with no mailbox behind it loses those replies. OquMail pairs the address with a real inbox and delivery logs at no cost.