---
title: "Backtesting: definition | Rex glossary"
description: "Testing a change to an automated process against past cases before using it on live work, to see what it would have done differently."
canonical: https://www.rex.inc/glossary/backtesting
---

# Backtesting

Testing a change to an automated process against past cases before using it on live work, to see what it would have done differently.

In AR, backtesting might replay last quarter's customer emails through a revised procedure, or rerun cash application with a new matching rule, then compare the results with what actually happened.

It turns process changes from guesswork into evidence, and catches unintended effects before they reach customers.

How Rex helps

Simulate

Backtest changes before running in production.

[See how it works](https://www.rex.inc/platform#simulate)

## Related terms

- [Agent operating procedure A written procedure that tells an AI agent how to handle a type of work, encoded from the standard operating procedures a finance team already follows.](https://www.rex.inc/glossary/agent-operating-procedure)
- [Supervised autonomy Giving an AI agent independence in stages: it starts by proposing actions for approval and runs on its own only as its work proves reliable.](https://www.rex.inc/glossary/supervised-autonomy)

Next step

Accelerate your receivables operation with Rex

A short walkthrough of agents working your accounts under your guardrails, with your team on the exceptions.

[Learn more](https://www.rex.inc/learn-more)

[Back to the glossary](https://www.rex.inc/glossary)