# Transactional analysis

Transactional analysis is the Glass Data layer that evaluates individual events — typically payments and transactions — in real time and returns a risk recommendation to support operational decisions.

Unlike [metrics and monitors](/en/behavioral/), which observe aggregated trends over time, transactional analysis processes each event in isolation, at the moment it happens.

## How it works

For every event received, the platform runs the sequence below:

1. **Risk score**: the platform calculates a score from 0 to 100 based on predictive models and the event data.
2. **Default recommendation**: the score is translated into a recommendation — `allow`, `challenge`, or `deny` — according to the account's [analysis configuration](/en/transactional/analysis/).
3. **Rules**: if the API call references a [rule](/en/transactional/rules/), its conditions are evaluated and may override the default recommendation.
4. **Response**: the final recommendation is returned in the API response, along with the details behind the decision.

## Components

- [Analysis](/en/transactional/analysis/): score ranges that define the account's default recommendation.
- [Rules](/en/transactional/rules/): custom logic that overrides the default recommendation based on business criteria.
- [Lists](/en/transactional/lists/): data sets used as parameters in rules.

## When to use

Use transactional analysis when you need an automated per-event decision — for example, to authorize or decline a payment, require additional verification, or route a transaction to manual review. To track operational behavior over time, combine it with [metrics and monitors](/en/behavioral/).

## Table of contents

- [Analysis](/en/transactional/analysis/index.html.md)
- [Expression syntax](/en/transactional/expression-syntax/index.html.md)
- [Rules](/en/transactional/rules/index.html.md)
- [Rules in the API](/en/transactional/rules-api/index.html.md)
- [Lists](/en/transactional/lists/index.html.md)
- [Versioning](/en/transactional/versioning/index.html.md)
- [Payment modeling](/en/transactional/payment_modeling/index.html.md)