Postmark is ActiveCampaign’s transactional email service, famous for deliverability focus, message streams, and publishing its own time-to-inbox metrics.
Postmark’s paid plans start at $15/month for 10,000 emails. MailBlastr’s entry plan costs slightly less and includes 50,000 emails — five times the volume — plus 2,500 contacts and 10 domains.
Postmark’s free developer plan is 100 emails/month — enough to test, not to launch. MailBlastr’s free tier is 3,000/month with 1,000 contacts, campaigns, and automations included.
Postmark added broadcast message streams, but there are no journey automations, A/B testing, segments, or polls. MailBlastr ships the full marketing layer in every plan.
Postmark charges $50/month per dedicated IP (and requires 300k+ monthly volume). MailBlastr’s managed dedicated IP add-on on Scale costs a fraction of that.
If you send modest volumes of purely transactional mail where every message is revenue-critical — password resets, receipts, magic links — Postmark’s single-minded deliverability focus, stream separation, and support quality are hard to argue with.
The free tier (3,000 emails/month) needs no card — you can run the whole migration before paying anything.
Add your sending domain and follow the guided DKIM, SPF, and DMARC setup. One-click flows exist for Cloudflare, GoDaddy, and Namecheap; verification usually completes in minutes.
Replace your current send with one HTTPS request or a typed SDK in 8 languages. Batch endpoints, idempotency keys, and scheduling are built in.
Subscribe a webhook to delivered, opened, clicked, bounced, complained, and unsubscribed events — every request is signed so you can verify the source.
Bring audiences over via CSV or the contacts API; templates port as plain HTML or rebuild in the block editor.
The send call, after the switch
curl -X POST https://www.mailblastr.com/api/emails \
-H "Authorization: Bearer mb_xxxxxxxx" \
-H "Content-Type: application/json" \
-d '{
"domain": "acme.com",
"from": "Acme <hello@acme.com>",
"to": ["ada@example.com"],
"subject": "Welcome to Acme",
"html": "<p>You are in.</p>"
}'| Feature | MailBlastr | Postmark |
|---|---|---|
| Free tier | 3,000 emails/month (100/day), 1,000 contacts, 1 domain — no card required | 100 emails/month (developer plan) |
| Entry paid plan | $14/mo — 50,000 emails, 2,500 contacts, 10 domains | $15/mo — 10,000 emails (Basic) |
| 100k emails/month | $24/mo (Pro 100k) · $63/mo (Scale, 1000 domains) | Volume tiers above $15–18 base; overage $1.20–$1.80/1,000 |
| Extra volume | $0.90 per 1,000 emails — credits never expire | $1.20–$1.80 per 1,000 |
| Transactional + marketing in one | API sends, campaigns, automations, and audiences in every plan | Broadcast streams only — no automations or A/B |
| Contacts & audiences | Included on every plan — 1,000 on Free, up to 250,000 on stock plans | No audience/contact management |
| Automations | Included — visual automations, 10,000 runs/month | ✗ |
| A/B testing | ✓ | ✗ |
| Inbound receiving | ✓ | ✓ |
| Event webhooks | Signed webhooks: delivered, opened, clicked, bounced, complained, unsubscribed | ✓ |
| Official SDKs | 8 languages + CLI | SDKs for major languages |
| Log retention | 30 days on every plan | 45 days activity (custom retention on Pro+) |
| Dedicated IP | Add-on on Scale — $21/30 days | $50/mo, requires 300k+ monthly volume |
| INR billing for India | ✓ | ✗ |
Postmark pricing and features summarized from public pricing pages, last checked 2026-08-02. MailBlastr figures come from the live plan catalog.
Want the row-by-row breakdown? See the full MailBlastr vs Postmark comparison.
At entry level, yes and by a wide margin of included volume: about the same monthly price buys 10,000 emails on Postmark Basic versus 50,000 on MailBlastr, which also includes contacts, campaigns, and automations.
Postmark has earned its reputation and publishes its own metrics — take that seriously. MailBlastr runs the same authentication stack (DKIM, SPF, DMARC, guided setup), automatic bounce/complaint suppression, and per-domain reputation isolation; for authenticated senders with clean lists, inbox placement is determined far more by your domain reputation than by the ESP logo.
Via broadcast message streams, yes — but without journey automations, segments, A/B testing, or polls. If your marketing needs end at “send a newsletter to a list”, Postmark can do it; beyond that MailBlastr’s included marketing layer goes further.
Postmark bills overage automatically at $1.20–$1.80 per 1,000 once you exceed plan volume. MailBlastr uses prepaid credits that never expire and cost less per 1,000.
Domain verification, then swap the send call — MailBlastr’s POST /emails accepts the same shape of from/to/subject/html payload — and re-point webhooks. Message-stream separation maps to sending domains or topics on MailBlastr.
Free tier with 3,000 emails a month — API, campaigns, automations, and webhooks included. No card required.