Customer.io is a behavioral messaging platform for lifecycle marketing — data-driven journeys across email, push, in-app, and SMS, priced by profile count.
Customer.io starts at $100/month and its power assumes you feed it behavioral data pipelines. If the job is transactional email plus campaigns, segments, and a handful of automations, MailBlastr does that from a fraction of the price — free tier included.
MailBlastr’s core is a transactional REST API with typed SDKs, signed webhooks, batch sends, idempotency, and 30-day searchable logs; the marketing layer shares the same rails. Customer.io’s transactional messaging exists but the platform’s center is journeys.
Customer.io bills by profiles stored — every signup raises the bill even if you never message them. MailBlastr prices by sending volume with contact allowances included, which matches how product email actually scales.
Customer.io rewards teams that invest in data instrumentation and journey design. MailBlastr’s automations (triggers, delays, conditions) cover the lifecycle basics — welcome series, onboarding nudges, win-backs — without a data project first.
If lifecycle messaging IS your growth engine — complex branching journeys on behavioral events across email, push, and SMS, run by a team that lives in the tool — Customer.io is built for exactly that, and MailBlastr does not pretend to replace it.
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 | Customer.io |
|---|---|---|
| Free tier | 3,000 emails/month (100/day), 1,000 contacts, 1 domain — no card required | Trial only |
| Entry paid plan | $14/mo — 50,000 emails, 2,500 contacts, 10 domains | $100/mo — 5,000 profiles (Essentials) |
| 100k emails/month | $24/mo (Pro 100k) · $63/mo (Scale, 1000 domains) | Custom — scales by profiles + volume |
| Extra volume | $0.90 per 1,000 emails — credits never expire | Profile/volume tier increases |
| Transactional + marketing in one | API sends, campaigns, automations, and audiences in every plan | Omnichannel journeys platform (email one channel of several) |
| Contacts & audiences | Included on every plan — 1,000 on Free, up to 250,000 on stock plans | The pricing axis (profiles) |
| Automations | Included — visual automations, 10,000 runs/month | Best-in-class journeys |
| A/B testing | ✓ | ✓ |
| Inbound receiving | ✓ | ✗ |
| Event webhooks | Signed webhooks: delivered, opened, clicked, bounced, complained, unsubscribed | ✓ |
| Official SDKs | 8 languages + CLI | SDKs + data pipelines |
| Log retention | 30 days on every plan | Plan-dependent |
| Dedicated IP | Add-on on Scale — $21/30 days | Available on higher tiers |
| INR billing for India | ✓ | ✗ |
Customer.io 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 Customer.io comparison.
For transactional email plus everyday lifecycle marketing (welcome series, onboarding, newsletters, win-backs) — yes, at a far lower price. For deep behavioral orchestration across push, in-app, and SMS with data-pipeline integrations, Customer.io remains the specialist.
Customer.io Essentials starts at $100/month for 5,000 profiles. MailBlastr’s entry plan is a small fraction of that and includes 50,000 emails/month, 2,500 contacts, automations, and A/B testing; there is also a real free tier.
Yes — the events API can enroll contacts into automations, and journeys support triggers, delays, and conditions. Customer.io’s journey engine is deeper (branching on arbitrary behavioral queries); MailBlastr covers the common lifecycle patterns.
No — email only, deliberately. If you need omnichannel today, Customer.io (or Brevo) fits better.
Export profiles to CSV or sync via the contacts API, rebuild key journeys in the automation builder, port templates as HTML, verify your domain, and point transactional sends at POST /emails or an SDK.
Free tier with 3,000 emails a month — API, campaigns, automations, and webhooks included. No card required.