Knock vs MailAnvil: Notification Infrastructure vs Transactional Email API
Knock vs MailAnvil: Notification Infrastructure vs Transactional Email API
Knock (knock.app) shows up whenever a team outgrows raw email sending and starts googling "notification service". It is a genuinely good product — but it solves a different problem than a transactional email API, and the pricing gap between the two is about 10x. This guide walks through what that 10x buys, so you don't pay for orchestration you don't need (or skip it when you actually do).
What Knock actually is
Knock is notification infrastructure. You build a workflow — "trial ending soon" — and Knock routes it across channels: email, in-app feed, push, Slack, SMS. It handles batching ("digest all activity into one 9 AM email"), per-user channel preferences, in-app feed components for your frontend, and read-state aware conditional sending. Email is one output of a routing engine, not the product.
Verified pricing (checked October 2026 directly on knock.app/pricing):
- Developer — $0/month: 10,000 messages/month, 500 guide active users, 500 AI agent credits
- Starter — $250/month: 50,000 messages included, then $0.005 per message ($5 per 1,000), 2,500 guide active users
- Enterprise — contact sales
A "message" in Knock's terms is one message sent to one user on one channel — so a workflow that emails and in-app-notifies the same user counts twice. At 100,000 messages/month a Starter-plan customer pays roughly $500/month. At 250,000, about $1,250/month.
What MailAnvil actually is
MailAnvil is a transactional email API. There is no workflow engine, no in-app feed, no channel routing. You call one REST endpoint (or the MCP tool, if you're wiring up an AI agent) and the email is sent through SES with DKIM/SPF handled on Cloudflare's edge. Webhooks tell you delivered, bounced, or complained.
Verified pricing (IDR-first):
- Free — Rp 0, 3,000 emails/month
- Pro — Rp 249rb/month, 50,000 emails
- Max — Rp 749rb/month, 100,000 emails
At 100,000 emails/month that's Rp 749rb — roughly $47 at Rp 16,000/USD. Knock's equivalent volume is about $500/month: ~10.7x more expensive — because you're also buying the orchestration layer.
The code difference
Sending a password reset through Knock requires a workflow to exist first (created in the dashboard or via API), a recipient identified in Knock's user system, and a template attached to the email channel step:
curl -X POST https://api.knock.app/v1/workflows/trial-ending/trigger \
-H "Authorization: Bearer sk_knock_" \
-H "Content-Type: application/json" \
-d '{"recipients": ["user_42"], "data": {"trial_end": "2026-10-20"}}'
With MailAnvil, the email is the unit of work:
curl -X POST https://api.mailanvil.com/v1/emails \
-H "Authorization: Bearer sk_live_..." \
-d '{
"from": "[email protected]",
"to": "[email protected]",
"subject": "Your trial ends Oct 20",
"html": "<p>2 days left. <a href=\"...\">Upgrade</a></p>"
}'
Two honest observations. First, Knock's model wins when the same notification must hit email + in-app + push with user preferences respected — you'd otherwise write and maintain that fan-out yourself. Second, Knock's model is heavier for pure email: user records, workflow definitions, and per-channel templates replace a single HTML string, and every message routes through Knock's message pricing even though only the email leg costs them anything meaningful.
Which one do you need?
- Just transactional email — OTPs, invoices, password resets, receipts. MailAnvil. There is no orchestration problem to solve; don't pay 10x for one.
- Multi-channel notifications with digests, preferences, in-app inbox — Knock earns its price, and you still need an email provider underneath for high-volume transactional mail. Many teams use both: Knock for product notifications, a direct email API for SMTP-level volume like billing and security emails (Knock's own docs recommend keeping critical email flows separate).
- Indonesian SaaS, IDR bank account — Knock bills in USD by card. MailAnvil bills in Rupiah with QRIS and GoPay, documents and supports in Bahasa, and your API calls terminate at Cloudflare's Jakarta edge rather than a queue in Virginia.
The build-it-yourself middle ground
The workflow Knock sells is, in the small, a cron job plus a database query: collect events, batch them, send one email. Teams with a single digest email frequently hand-roll it and it works fine until per-user preferences and channel fan-out appear. The failure mode isn't the code — it's the maintenance surface (preference management, read-state, retry semantics per channel). That maintenance surface is what the 10x is actually priced on.
Bottom line
Knock and MailAnvil overlap only on the email channel. If your roadmap says "notification system", evaluate Knock seriously. If your roadmap says "send email reliably and cheaply", the ~$5/1,000 vs ~Rp 15rb/50k pricing comparison answers itself — and Indonesian teams get the further advantage of paying in the currency their bank actually holds.