I built a small developer tool called *SimGate*.
Problem: most SMS APIs (Twilio, etc.) charge per-SMS. For small projects, prototypes, or local businesses, this adds up quickly.
What I made: - An Android app that connects your phone to the cloud via WebSocket. - A simple REST API where you send JSON (`deviceId`, `phoneNumber`, `message`). - Your phone sends the SMS using its own SIM plan — no extra per-SMS fees.
Use cases: OTP codes, alerts, internal tools, or any project where you just need reliable SMS without provider costs.
Stack: Node/Express + Websockets (backend).
Demo & docs: https://simgate.app
This is my first SaaS launch. I’d love feedback: - Would you use this for side projects or small businesses? - Any concerns about reliability/security with this model?
Thanks!
jqpabc123•4mo ago
SMS on a typical phone plan in the USA is contractually limited to "personal use" only.
I've never experienced this personally, but I read that most carriers define "personal use" as a few hundred messages (1 message = 160 char. or less) per day. Automated high volume use can get your account suspended.
Also, your personal number will be available to recipients should they decide to reply. This also adds to this vaguely defined "personal use" limit.
Also, most carriers maintain an eMail to SMS gateway available for free "personal use". Just send a properly formatted email to the gateway domain and the body will be sent as SMS --- no additional charge. But the required gateway domain is that of the recipient's service provider. Low cost carrier lookups are available from various sources.
https://www.geeksforgeeks.org/techtips/forward-email-as-a-te...
https://github.com/mfitzp/List_of_SMS_gateways/
https://www.carrierlookup.com/