Mailer To Go vs MailAnvil: SMTP Add-on vs REST Email API
Mailer To Go built its name as a Heroku add-on: attach it to your dyno, get authenticated SMTP sending with managed SPF/DKIM/DMARC, done in minutes. It's a solid product — if your stack is Heroku and SMTP is enough. But for developers in Indonesia building modern transactional email into their apps, two gaps matter: there's no REST API (it's "in development" per their own pricing page), and there's no free plan at all.
Here's the side-by-side.
The fundamentals
| Mailer To Go | MailAnvil | |
|---|---|---|
| Protocol | SMTP only (REST API in development) | REST API + SMTP |
| AI agent access | Resource hub content | Native MCP server at mcp.mailanvil.com |
| Free tier | None — every plan paid | 3,000 emails/mo free |
| Payments | Card only | QRIS, GoPay, card |
| Docs | English | English + Bahasa Indonesia |
| Infrastructure | Managed subdomain delegation | Cloudflare Workers + AWS SES, edge delivery |
Mailer To Go's pitch is simplicity: one NS-record delegation, they publish and auto-rotate your DNS records, reputation lives on a dedicated sending subdomain. That's genuinely nice if you hate DNS. MailAnvil does the equivalent — automated DKIM on Cloudflare DNS, suppression lists, bounce handling — but you drive it with a REST API instead of SMTP credentials.
Pricing at 50,000 emails/month
Mailer To Go's Starter is $15/mo for 25,000 emails, then $1.00 per 1,000 over. At 50k that's $15 + $25 = $40/mo. At today's rates (~Rp 16k/USD) that's about Rp 640rb/bulan.
MailAnvil Pro is Rp 249rb/bulan for 50,000 emails flat.
That's roughly 60% cheaper — and it's billed in rupiah through QRIS or GoPay, so no foreign-transaction card fees and no USD invoice reconciliation at month-end. For a small travel agency in Jogja sending 50k booking confirmations a month, that difference is a full workday of revenue.
Where Mailer To Go wins
Credit where due:
- Heroku/Addons.io/Build.io integration. If you provision as a marketplace add-on, billing flows through the platform. Nothing else on this list does that.
- No daily email limit on any plan — batch sends never stall.
- Pay-as-you-go overflow. Going over your plan bills at your tier's per-1,000 rate instead of hard-stopping critical mail.
MailAnvil's free tier does have a hard monthly cap (3,000), and paid plans map to fixed quotas. If your volume is wildly spiky and you live in Heroku, MTG's model can fit.
The API gap is the real story
SMTP-only sending means your code builds raw email payloads — headers, MIME boundaries, attachments — and hands them to a relay. Every modern email API (Resend, Postmark, Mailgun, MailAnvil) replaced that with POST /v1/send and a JSON body. For AI agents it goes one step further: an MCP server means Claude or any MCP-compatible agent can send email through tool calls with zero custom glue code.
Mailer To Go markets heavily to the AI-agent segment through its resources hub, but the transport is still SMTP. If you're building a fintech app that sends OTP codes, a food delivery platform that sends invoices, or a booking site that sends confirmations — you want an API call, a template ID, and a status webhook. That's the MailAnvil shape.
Verdict
Choose Mailer To Go if your app lives on Heroku, you want marketplace billing, and SMTP covers you. Choose MailAnvil if you want a REST API, MCP-native agent access, a free tier to start on, IDR pricing via QRIS/GoPay, and Bahasa Indonesia docs and support — at about 60% less at the 50k volume point.
Try MailAnvil free at mailanvil.com — 3,000 emails/mo, no card required.