Best Alternatives to Arcjet in 2025
Arcjet is a runtime security platform for AI agents that ships as code inside your application, helping teams detect prompt injection, authorize agent tool calls, redact sensitive data, and block bots and abuse in real time before an action happens. But depending on your stack, budget, or specific threat model, you may want to evaluate other options. Here are the best alternatives to Arcjet for securing AI agents and LLM applications at runtime.
Lakera Guard
Lakera Guard is a purpose-built LLM security API that detects prompt injection, jailbreaks, data leakage, and harmful content with a single API call. It offers strong detection accuracy, low latency, and easy integration, making it a direct alternative if you want a managed security layer without embedding code deeply into your app.
Prompt Security
Prompt Security provides runtime protection for GenAI applications and AI agents, covering prompt injection, data exfiltration, and unsafe tool use. It offers both inline and out-of-band deployment options, plus visibility into agent behavior, which suits enterprises needing governance alongside runtime blocking.
Robust Intelligence (Cisco AI Defense)
Robust Intelligence, now part of Cisco AI Defense, offers AI firewall and runtime guardrails for LLM apps and agents. It combines automated red teaming with runtime enforcement, making it a strong fit for organizations that want continuous validation plus real-time protection in one platform.
Protect AI (Guardian)
Protect AI's Guardian provides a firewall for AI models and LLM applications, detecting prompt injection, malicious inputs, and model abuse. It integrates with existing ML pipelines and offers centralized policy management, appealing to teams already using Protect AI's broader AI security suite.
HiddenLayer
HiddenLayer focuses on securing AI models and agents against adversarial attacks, model theft, and runtime manipulation. Its platform offers real-time detection and response for AI workloads, making it a good alternative if your priority is protecting both the model and the agent runtime from sophisticated threats.
CalypsoAI
CalypsoAI offers an AI security platform with runtime guardrails, red teaming, and model-agnostic policy enforcement. It is designed for enterprises deploying AI at scale and provides visibility and control over agent interactions, tool calls, and data flows, similar to Arcjet's runtime focus.
Noma Security
Noma Security provides end-to-end AI security spanning discovery, posture management, and runtime protection for AI agents and applications. It emphasizes agentic AI security with tool-call authorization and data flow controls, making it a viable alternative for teams needing broad AI security coverage beyond just runtime blocking.
Arcjet stands out for embedding runtime security directly in your code to protect AI agents before actions execute. If you need a managed API, enterprise governance, or broader AI security coverage, Lakera Guard, Prompt Security, Robust Intelligence, Protect AI, HiddenLayer, CalypsoAI, and Noma Security are all strong alternatives. Evaluate them based on your deployment model, latency requirements, and whether you need pure runtime enforcement or a fuller AI security platform.