Documentation

Transformations and Preview

The transformation model inside ETL Builder and why preview is central to the user journey.

7 minutesETL usersValidated 2026-05-15
Before you start
  • Input source selected

ETL Builder supports major ETL operations such as:

  • field selection
  • row filtering
  • sorting
  • field management and calculated values
  • expression-driven transforms
  • spatial joins
  • spatial grid and geometry stages
  • custom logic stages
  • multiple writer targets

Why preview matters

Tamaat's ETL user journey is intentionally preview-driven. Many stages can show users how the data changes before they run the entire flow. That reduces trial-and-error and helps users understand the impact of each stage while they build.

How to build a flow responsibly

  1. Add the reader first and validate the incoming fields.
  2. Add one transformation stage at a time.
  3. Use preview after each important stage instead of waiting until the end.
  4. Save and run manually before attaching a schedule.

What preview is doing for the user

Preview is not just a convenience. It is one of the main reasons the platform is easier to use. It helps users understand:

  • which rows survive a filter
  • how a field calculation changes values
  • whether a join is behaving the way they expect
  • whether a writer is receiving the data shape they intended