AWS WAF introduces dynamic label interpolation for custom request and response handling

This article announces dynamic label interpolation in AWS WAF, enabling security engineers to forward WAF classification signals to origins and embed context in responses using a single rule.

• Use ${namespace:} syntax to forward entire label namespaces in custom headers and response bodies
• Eliminates need for separate rules for each signal value
• Introduces synthetic labels: client IP, WAF request ID, JA3/JA4 fingerprints
• Embed reference IDs in block/challenge pages for false positive reporting
• Works with AWS Managed Rules, Marketplace rule groups, and custom labels
• Headers automatically adapt as new labels are added to namespace
• Available in all AWS Regions at no additional cost

Dynamic label interpolation simplifies WAF configuration by consolidating multiple rules into single rules with dynamic variables, improving operational efficiency for security teams.