Fastly puts model routing, AI budgets and prompt-injection controls into the edge request path

Fastly announced AI Runtime Control, AI Firewall and new API Security capabilities on September 21. Runtime Control provides a single endpoint across public and self-hosted model providers with virtual provider keys, token/spend visibility, rate limits, budget controls and failover. AI Firewall evaluates prompts in the edge request path to identify and block LLM-oriented attacks such as prompt injection. API Security can enforce API contracts against agentic and conventional traffic, observing or blocking requests that use unsupported operations or malformed payloads. Fastly says all three capabilities are now available.

Teams putting AI into production increasingly assemble separate products for model routing, cost governance, LLM security and agent authorization. Fastly is making those controls part of the edge infrastructure already carrying application traffic. That can reduce the number of gateways in a request path and make policy consistent across ordinary APIs, AI applications and autonomous agents. The trade-off is concentration: model access and AI security become more dependent on one edge control plane, and Fastly’s security/economic claims still need independent production evidence.

Applications can route model calls through one Fastly endpoint while retaining multiple public or self-hosted providers. Virtual keys keep underlying provider credentials out of applications, while token visibility, rate limiting, budget controls and failover move model economics and resilience into the routing layer.

AI Firewall evaluates prompts in the request path at the edge and is intended to block prompt-injection and related LLM attacks before they reach the target model. That differs from post-generation moderation or application-level checks because enforcement occurs on infrastructure already fronting the service.

Fastly’s API Security expansion treats autonomous and agent-assisted requests as API clients that still have to obey service contracts. Operators can observe or block calls that target unsupported operations, send malformed requests or otherwise fall outside defined API behaviour.

Fastly is combining AI routing and security with its existing bot management, WAF, DDoS and API tooling. For teams already on Fastly, that creates a path to govern human, application and agent traffic without adding another dedicated AI proxy. For teams that value provider independence, the same consolidation increases the blast radius of Fastly configuration or availability failures.