Blog
Shadow traffic and canaries: validating CORS headers on duplicated requests
Mirror production traffic to new builds without user impact; compare header sets byte-by-byte for drift.
1 min read
testingcanarycors
Privacy and sampling
Redact cookies and PII from mirrored payloads in shadow pipelines.
Sample traffic to control storage costs while keeping statistical significance.
Release gates
Block promotion if OPTIONS or Allow-Origin differs between shadow and baseline beyond tolerance.
Keep shadow environments network-isolated from production databases.