Engagement you own

Every serious app needs to reach its users — a trial-ending nudge, a shipped-order push, a re-engagement email. But the tools to do it well are closed, expensive, and hold your data and deliverability hostage.

Retainza flips that. It's a developer-first platform for the five things that actually move retention: email, push, in-app messages, deep-link navigation, and conditional automated sends. You bring your own FCM and SMTP — so we never own your delivery cost or your inbox reputation.

It's multi-tenant from day one, with the Project as the isolation boundary. Secrets are encrypted at rest with envelope encryption — a fresh data key per secret, wrapped by a master key that never leaves the process. And clean Store and Channel adapter seams mean you can move from in-memory to Postgres, or swap any channel, without a rewrite.

Start free on the hosted dashboard and scale only as your usage does — your data and your credentials stay yours throughout.