A relay platform is an intermediary service that forwards requests to another service instead of answering directly. In cyber security, relays sit between the user and the final provider, such as an API, model endpoint, payment service, or internal application. Because the relay can see, transform, log, or delay traffic, it becomes part of the trust boundary. Even if the final service is secure, the relay may still expose sensitive data in request bodies, headers, cookies, or diagnostic traces.
Relay platforms matter because attackers often target the middle of a workflow, not just the endpoint. A compromised or over-privileged relay can leak prompts, credentials, session tokens, or customer records, and misconfigured logging can create unintended copies of that data. Defenders reduce risk by minimizing stored content, disabling verbose debug output, authenticating upstream calls, encrypting traffic end to end, and clearly documenting what the relay can observe and retain. In practice, a relay is useful for routing and abstraction, but it should never be treated as a harmless pass-through.