SendGrid vs Resend vs Postmark — the 2026 deliverability comparison

We've sent 4M+ transactional and marketing emails through SendGrid, Resend, and Postmark over the last year via Conduit. Here's the side-by-side on deliverability, pricing, and operational fit.

The three providers

SendGrid (Twilio)

The incumbent. Acquired by Twilio in 2019. Sends massive volume (billions/day). Strong API, mature dashboards, often used by enterprise. Pricing: free up to 100 emails/day; paid tiers start at $19.95/mo for 50K emails.

Resend

The modern challenger. Founded 2023, developer-focused. Clean API, React Email templates, slick dashboards. Pricing: free up to 3K emails/mo; paid tiers start at $20/mo for 50K emails.

Postmark

The deliverability specialist. Known for high inbox placement, strict onboarding. Pricing: $15/mo for 10K emails.

Inbox placement benchmark

We ran the same template (Bamberg Digital newsletter, ~3K subscribers) across all three providers over 30 days. Inbox placement results (Gmail, Outlook, Yahoo, others):

Provider	Gmail inbox	Outlook inbox	Yahoo inbox	Overall
Postmark	97%	95%	94%	96%
Resend	96%	94%	93%	95%
SendGrid	92%	91%	89%	91%

Caveats: same content, but sender domain reputation differs. Postmark's edge is partly due to their strict onboarding (they audit senders before approving high volume).

Pricing at scale

At 100K emails/month:

• SendGrid Essentials: $19.95/mo
• Resend Pro: $20/mo
• Postmark Streams: $50/mo

At 1M emails/month:

• SendGrid Pro: $89.95/mo
• Resend Business: $90/mo
• Postmark Streams: $500/mo

Postmark is significantly more expensive at volume. The trade is: better deliverability, stricter abuse protection.

Operational maturity

SendGrid

Most mature. Best for ops teams already familiar with Twilio. Strong webhooks, mature retry logic, granular suppression management. Downsides: aging UI, slower feature velocity, mixed deliverability reputation (varies by IP pool).

Resend

Fastest-improving. Best for developer-first teams. Clean API, React Email integration, snappy UI. Downsides: smaller IP pool (less reputation diversification), newer team (less battle-tested at extreme volume).

Postmark

Most opinionated. Best for teams that prioritize deliverability over everything else. Strict abuse policies (they'll suspend you for poor list hygiene). Downsides: more expensive, harder onboarding, less feature-rich UI.

Which one to use for what

Transactional (receipts, password resets, account notifications)

Postmark. Their core competence. Strict separation of transactional from marketing means your password reset emails won't share IP reputation with your newsletter.

Marketing newsletter (3K-30K subscribers)

Resend at small scale, SendGrid if you outgrow Resend's pricing. Both handle list hygiene + segmentation reasonably.

Cold outbound (5K-50K sends/day)

None of the three. Cold outbound from SendGrid / Resend / Postmark gets flagged fast. Use AWS SES with dedicated IPs + a mailbox rotation pool (Google Workspace / Microsoft 365 mailboxes via OAuth). Conduit Outreach supports this natively.

Mixed (transactional + marketing + cold outbound)

Split: Postmark for transactional, Resend for marketing, SES + mailbox rotation for cold outbound. Conduit supports all three under one workspace.

Common operational mistakes

1. Mixing transactional and marketing on the same provider/domain. This causes transactional deliverability to suffer when marketing list quality degrades. Always separate.
2. Not warming up new IP / new sender domains. New IPs send a small volume signal that must build over 2-6 weeks. Sending 50K in week 1 from a new IP is a deliverability disaster.
3. Ignoring webhook events. Bounce, complaint, and delivery webhooks are how you maintain list hygiene. Wire them into your contact database.
4. Skipping DMARC enforcement. p=none is not protection. Move to p=quarantine ASAP after monitoring.
5. Sending on a shared IP pool by default. SendGrid's shared pools have variable reputation depending on who else is sending. Dedicated IP is worth the cost above 100K sends/month.

The Conduit integration

Conduit's Outreach module supports SendGrid, Resend, Postmark, SES, Mailgun, and BYO SMTP. You can route different message types to different providers from the same workspace:

• Transactional confirmations → Postmark
• Newsletter → Resend
• Cold outbound → SES + mailbox rotation

Each provider has its own deliverability dashboard, its own warmup curve, its own bounce + complaint webhook handling. Conduit tracks per-provider reputation and warns when a provider's reputation degrades.

Bottom line recommendations

• For transactional: Postmark.
• For marketing newsletter: Resend up to 100K/mo, SendGrid above.
• For cold outbound: SES + mailbox rotation via Conduit Outreach.
• For mixed: All three via Conduit.

Want help designing your sender strategy? Contact Bamberg Digital for a free deliverability audit.