Blog

Notes on SMS, deliverability, privacy, and the AI reply loop.

• 2026-09-19·Engineering·6 min

  Why your Android phone is a better SMS gateway than Twilio

  A single mid-range Android with an unlimited plan costs ~$0 per SMS. Twilio charges $7.50 per 1,000. Here is the math and the caveats.

• 2026-09-19·AI·5 min

  How to make an AI SMS auto-reply sound human

  A prompt template, a confidence gate, and a handful of vetoes. What we learned iterating on Gemini for our free auto-reply.

• 2026-09-20·Privacy·3 min

  Why we delete your SMS after 24 hours

  Messages are the most sensitive thing we could store. So we mostly don't. Here is exactly what is kept, for how long, and why.