---
title: "Preview databases"
description: "Every API preview gets an ephemeral Postgres with migrations and seed data - isolated from production."
url: https://evonx.ai/docs/preview-and-debug/preview-databases
locale: en
updated: 2026-09-04
---

# Preview databases

Every API preview gets an ephemeral Postgres with migrations and seed data - isolated from production.

When a preview includes your API, Evonx gives it a database of its own: a fresh,
ephemeral Postgres created for that preview, migrated to the current schema and
loaded with seed data. Nothing you do in a preview can touch production data.

## What you get, automatically

1. A **dedicated Postgres instance** spins up alongside the preview — not a shared
   database, and never your production one.

2. **Migrations run** so the schema matches the code being previewed. If the
   change you're testing alters the data model, the preview database already
   reflects it.

3. **Seed data loads** — realistic sample records (customers, jobs, appointments,
   whatever your app's domain defines) so screens render with content instead of
   empty states.

When the preview is [cleaned up](/docs/preview-and-debug/preview-hub), its
database goes with it.

## What this means in practice

- **Test destructively.** Delete records, cancel appointments, corrupt a workflow
  on purpose — the worst case is restarting the preview for a fresh copy.
- **Data doesn't persist between previews.** Each preview starts from migrations
  plus seed data. If a test needs specific records, add them at the start of the
  session — or ask the AI to extend the seed data so every future preview includes
  them.
- **Schema changes get exercised safely.** A thread that alters the data model
  proves its migrations by running them here first, before they ever touch
  [your managed production database](/docs/launch/managed-database).

> **Warning**
> Seeing production-like data in a preview? You're not — seed data is deliberately
> realistic. But that's also the standard to hold it to: if your seeds are
> placeholder junk, ask the AI to generate seeds that resemble your real business,
> so previews actually rehearse reality.

## Related

- [Managed database](/docs/launch/managed-database) — the production counterpart.
- [Reading preview logs](/docs/preview-and-debug/reading-logs) — the database
  preparation phase in the boot logs.