Engineering Blog
How we build
email + AI.
Deep dives on the infrastructure, AI agents and reliability work behind SlyReply — from the people who ship it. Here for the product instead? Read the docs .
The email is the app
Why SlyReply has no inbox UI: SMTP is the interface, your From address is the login, and we store zero message bodies. How the pieces fit.
Andrew9 min read
architectureemailsmtpprivacysecurity
Fictional users that write real reviews
We test SlyReply with a couple of dozen fictional people — AI personas that drive the real product and write honest reviews. Here's how, and why it beats more assertions.
Andrew7 min read
ai-agentstestinginfrastructure
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