Postmark and SendGrid both send transactional email well, but they are built for different buyers. Postmark (owned by ActiveCampaign) is a focused, transactional-only service known for fast delivery, with plans starting at 10k emails. SendGrid (owned by Twilio) is a broad platform for transactional and marketing email, with cheaper published tiers at 50k–100k and a dedicated IP included on Pro. At very low volume, Postmark is a little cheaper; above that, SendGrid's tiers usually are.
All prices are as of October 2026, from third-party pricing trackers. Please confirm on Postmark's pricing page and SendGrid's pricing page.
Postmark vs SendGrid at a glance
| Postmark (ActiveCampaign) | SendGrid (Twilio) | |
|---|---|---|
| Free option | Developer: 100 emails/month | Trial: 100 emails/day for 60 days |
| 10k emails/month | Basic $15, Pro $16.50, Platform $18 | Essentials: $19.95 (covers up to 50k) |
| 50k emails/month | Check their pricing page | Essentials: $19.95/mo |
| 100k emails/month | Check their pricing page | Essentials: $34.95/mo; Pro: $89.95/mo |
| 300k emails/month | Check their pricing page | Pro: ~$249/mo |
| 2.5M emails/month | Check their pricing page | Pro: up to ~$1,099/mo |
| Overage | Basic $1.80, Pro $1.30, Platform $1.20 per 1,000 | Check their pricing page |
| Dedicated IP | Check their pricing page | Included on Pro |
| Inbound email | Included from the Pro plan | Inbound Parse webhook |
| Marketing email | Transactional-only focus | Marketing Campaigns, separate (from ~$15/mo) |
| Developer experience | Focused transactional API | Broad platform and dashboard |
How much do Postmark and SendGrid cost?
At 10k emails a month, Postmark's plans cost $15 (Basic), $16.50 (Pro) or $18 (Platform). SendGrid Essentials is $19.95. So Postmark is a few dollars cheaper at this volume.
From 10k to 50k, SendGrid Essentials stays at $19.95. On Postmark, volume above 10k is billed at $1.20–1.80 per 1,000 depending on plan, unless a larger tier fits better. We don't have reliable figures for Postmark's higher tiers, so check their pricing page.
At 100k, SendGrid Essentials is $34.95 on shared IPs, or Pro at $89.95 with a dedicated IP. For Postmark at 100k, check their pricing page. Our email cost calculator can help you compare, and SendGrid pricing explained walks through SendGrid's plan structure.
Free options
Neither is meant for free production use. Postmark's Developer plan gives 100 emails a month on an ongoing basis. SendGrid's trial gives 100 a day for 60 days. Both are fine for building and testing an integration.
Transactional focus vs broad platform
This is the main philosophical difference.
Postmark focuses on transactional email: password resets, receipts, alerts. It is known for fast delivery of those messages. Keeping bulk marketing out of the picture is the point, and it appeals to teams that want predictability for critical mail.
SendGrid covers transactional and marketing email, templates, inbound parsing and a large dashboard. Marketing Campaigns is priced separately (from around $15/month). If you want one vendor for everything, SendGrid offers more.
Dedicated IPs
SendGrid includes a dedicated IP on Pro (from $89.95/month for 100k). For Postmark, dedicated IP options were not in our sources, so check their pricing page. A dedicated IP isn't automatically better: it needs consistent volume and a proper warm-up. Our shared vs dedicated IP guide explains when it makes sense.
Inbound email
Both can receive email for your app. Postmark includes inbound processing from its Pro plan ($16.50/month). SendGrid offers Inbound Parse, which posts incoming mail to your webhook. Check both vendors' docs for limits.
Developer experience
Both have mature APIs, SMTP support and SDKs for common languages. Postmark's product is narrower, so there is less to configure. SendGrid's dashboard and settings are broader, because the product is. Teams already on Twilio may find SendGrid easier to adopt through an existing account.
Does the provider change deliverability?
Less than people expect. Both providers run large, professionally managed sending infrastructure. What decides whether your mail reaches the inbox is mostly on your side:
- Authentication: SPF, DKIM and DMARC published correctly, with DKIM signed for your own domain so it aligns with the From address.
- List hygiene: not sending to addresses that bounced or complained. Both providers keep a suppression list for you.
- Content and expectations: recipients who asked for the mail and recognise the sender.
- Volume patterns: steady sending rather than sudden spikes, especially on a dedicated IP.
Where the provider does matter is in who else shares your IPs. Postmark's transactional-only focus is partly a promise about that: your password resets don't share a pool with bulk promotional mail. On SendGrid's shared Essentials plans, the provider manages its pools; if you want full control of your reputation, Pro's dedicated IP is the published route. If you are seeing spam placement on either, start with why emails go to spam before blaming the provider.
Switching between Postmark and SendGrid later
Picking one now doesn't lock you in. Both accept standard SMTP as well as their own APIs, so switching is mostly a configuration job:
- Add the new provider's DKIM and return-path records alongside the old ones.
- Update SPF so it stays a single record that covers what you need, within the 10-lookup limit.
- Change your app's credentials, or swap the API call.
- Export your suppression list from the old provider and import it into the new one.
- Move traffic over in stages, then remove the old records.
That last step matters more than it looks: removing DNS records while mail is still flowing through the old provider breaks DKIM for that mail. Our SendGrid migration guide walks through the same steps in detail, for a move to your own server.
Which should you choose?
Choose Postmark if:
- You send under about 10k transactional emails a month.
- You want a transactional-only service with a reputation for fast delivery.
- You need inbound processing on a published, low-cost plan.
Choose SendGrid if:
- You send 50k or more a month and want the lower published tiers.
- You want a dedicated IP bundled into a plan.
- You need marketing email from the same vendor, or already use Twilio.
Either way, inbox placement depends heavily on your authentication and sending habits. Make sure SPF, DKIM and DMARC are set up and aligned, and check the Gmail and Yahoo bulk sender requirements if you send more than about 5,000 a day to Gmail.
A third option: your own server
If neither rental model appeals, you can run your own mail server. A self-hosted Postfix server gives you your own IP, no per-email fees, and your mail data on your own machine. One server can send for several domains, each from its own IP if you want.
It isn't the low-cost choice at small volume. Up to about 100k emails a month, providers like these cost roughly $15–35, while a managed self-hosted server runs about $99/month plus a VPS (typically $5–20/month). Self-hosting tends to win on cost roughly above 200k a month, and on control and privacy at any volume. You also need to warm up the IP and monitor it.
See our Postmark alternative and SendGrid alternative pages for what switching involves. If you want it built or managed for you, see our plans and pricing.