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Mails.ai vs Siel

A side-by-side comparison built from both listings. Blank cells mean the company has not given that detail; we never guess.

Mails.ai compared with Siel
DetailMails.ai logo Mails.aiSiel logo Siel
What it doesEmail infrastructure for AI agents SMS API and CPaaS platform for OTPs and alerts
StageStartup Not given
FoundedNot given Not given
Based inNot given Not given
Pricing modelNot given Paid
PricingFree: 3,000 emails + 3,000 inbound replies/month; Pro: $20/month for 50K emails + 50K inbound replies; Scale: $99/month for 250K emails + 500K inbound replies. Yearly billing available: Pro $200/year, Scale $990/year (two months free). Not given
Key features
  • Per-agent email addresses on your domain
  • Native prompt-injection scanning on every inbound
  • Per-agent reputation graph
  • Typed reply events without raw MIME parsing
  • MCP-native distribution
  • Self-serve signup with no sales call
  • TypeScript and Python SDKs
  • HMAC-signed webhooks with retries
  • Per-agent allowlist and send limits
  • DKIM signing on custom domains
  • REST API and SMPP 3.4 protocol support
  • Routes tested on real phones
  • Campaign management with CSV import
  • OTP by SMS and Telegram
  • Fraud protection with spending and OTP limits
  • Real-time delivery analytics
  • Mobile apps for iOS and Android
  • Public pricing by country
  • Message price shown before sending
What makes it different
  • No approval queue—sending works immediately on signup
  • Prompt-injection scanning built into every inbound message
  • Per-agent reputation tracking so each agent is scored independently
  • Every route tested on real phones to verify delivery receipts
  • No monthly fee, no minimum contract required
  • Fraud protection stops invalid sends before charging
  • Message price and part count visible before sending
  • One platform across REST API, SMPP, web app and campaigns
Community votes00
DR (Domain Rating by Ahrefs)29 no change since last checkNot checked yet no change since last check
Trust Flow (Majestic)80
Citation Flow (Majestic)360
Referring domains (Majestic)4060

3 details filled in for both companies.

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