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Sendmux vs Siel

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

Sendmux compared with Siel
DetailSendmux logo SendmuxSiel logo Siel
What it doesEmail API that gives AI agents a real inbox with send, receive, and routing capabilities SMS API and CPaaS platform for OTPs and alerts
StageNot given Not given
FoundedNot given Not given
Based inNot given Not given
Pricing modelNot given Paid
PricingFree: $0/team/month with 2 mailboxes, $1 usage credit, 50 recipients/day. Pro: $7/team/month + usage. Connected outbound: $0.50/1,000 accepted recipients. Managed sending: $0.75/1,000. Inbound: $0.50/1,000 mailbox deliveries. Storage: $0.02/GB/month. Not given
Key features
  • Multi-provider outbound routing with weighted distribution
  • Dedicated inboxes with clean JSON parsing
  • Mailbox-scoped API keys
  • Signed webhooks and Server-Sent Events
  • Per-provider quotas at multiple time windows
  • Unified inbox view for all agent mailboxes
  • Message parsing reducing LLM token usage by 80%
  • 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
  • Brings your own email providers with automatic routing and failover instead of platform lock-in
  • Reduces LLM token consumption by up to 80% with structured JSON parsing and content cleaning
  • Multi-tenant architecture with mailbox-scoped credentials for agent isolation
  • 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)39 no change since last checkNot checked yet no change since last check
Trust Flow (Majestic)280
Citation Flow (Majestic)350
Referring domains (Majestic)2410

3 details filled in for both companies.

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