# How it works

Anonymizers work by processing all data that flows through Opik's tracing system - including inputs, outputs, and metadata - before it's stored or displayed. They apply a set of rules to detect and replace sensitive information with anonymized placeholders.

The anonymization happens automatically and transparently:

1. **Data Ingestion**: When you log traces and spans to Opik
2. **Rule Application**: Registered anonymizers scan the data using their configured rules
3. **Replacement**: Sensitive information is replaced with anonymized placeholders
4. **Storage**: Only the anonymized data is stored in Opik