Arcjet (site) is a runtime security platform for AI agents: it detects prompt injection, authorizes tool calls, redacts sensitive data, and blocks bots and abuse before an action executes. It has a free 15-day trial, then paid plans start at $25/month (Individual), $299/month (Startup), with custom Enterprise pricing plus usage-based fees. Below are alternatives that do similar runtime interception or agent-security work, ordered from cheapest to most expensive stated price.
| Product | Free tier | Starts at | Best for |
|---|---|---|---|
| AIBIM AI | Yes | Free (beta) | Teams testing runtime security with no budget yet |
| Kastra | Yes | $19.99/mo | Developers using Claude Code, Codex, Cursor, OpenClaw |
| SafeClaw | Yes | $20/mo | Teams that want hosting plus credit-based security |
| GnamiAI | Yes | $29/mo | Solo builders needing a sandboxed agent runtime |
| Runwall | Yes | Not stated | Small teams wanting a free runtime layer first |
| Runtime | Yes | $99/mo | Teams needing sandboxed coding agents at scale |
| Oconee Runtime | Yes | $750/mo | Enterprises with many users needing agent-execution controls |
AIBIM AI
AIBIM AI (site) offers runtime security for LLM apps and agents, currently free through a controlled beta with no pricing gate. It suits teams that want to try agent-level security monitoring before committing budget. Cost: free during beta, per the stated facts. The limitation is that no pricing has been published yet, so there's no guarantee what it will cost once beta access ends — plan for a future paid tier.
Kastra
Kastra (site) intercepts AI agent tool calls and evaluates them against deterministic, plain-English policies before execution, returning allow, hold, or deny decisions in under 1ms. It's built for developers using coding agents like Claude Code, Codex, Cursor, and OpenClaw. Pricing starts at $19.99/developer/month for Pro (15-day free trial, no card required), with Team at $49.99/developer/month (3-seat minimum) and custom Enterprise pricing. The Team plan's 3-seat minimum means small teams pay for seats they may not need.
SafeClaw
SafeClaw (site) provides security-first hosting for AI agents, combining runtime protection with the hosting layer itself. It fits teams that want agent hosting and security bundled together rather than a security layer added to existing infrastructure. Pricing starts at $20/month for the Pro plan (5,000 credits), with Operator at $50/month (15,000 credits) and a free tier of 1,000 trial credits. Because it's credit-based, costs can scale unpredictably with usage compared to flat-rate plans.
GnamiAI
GnamiAI (site) is a "safer AI agent runtime" offering cloud sandboxing and model support. It suits individual developers who want a free trial before paying and don't need enterprise-scale controls. The Pro plan costs $29/month for 12,500 cloud sandbox credits, all workspace modes, and model support; the app is free to try. Pricing is credit-based, so heavy usage could exceed the 12,500-credit allotment faster than expected.
Runwall
Runwall (site) is a runtime security layer meant to let AI agents execute safely, with a free tier for individual developers and small teams and a separate Pro plan for production-grade governance. It suits teams wanting to start free and only consider paying once they need advanced controls. Specific Pro plan pricing is not stated, so cost at scale is unclear until you contact them or check current plan details.
Runtime
Runtime (site) offers sandboxed coding agents for teams, with a free plan (500 credits) for individuals and a Teams plan for production use. It suits organizations that need sandboxing across multiple developers rather than a single security check. The Teams plan starts at $99/seat/month, with custom Enterprise pricing for advanced security needs — a per-seat model that gets expensive quickly for larger teams.
Oconee Runtime
Oconee Runtime (site) targets the broader enterprise security boundary created by AI agents that execute commands, modify files, and invoke tools against enterprise resources. It suits larger organizations, not solo developers or small teams. Pricing starts at $750/month for the Starter plan (10 users), with Growth at $1,500/month (25 users), Growth+ at $3,000/month (75 users), and custom Enterprise pricing; a 7-day free trial is available. At these prices it's the most expensive option here, well above Arcjet's own paid tiers.
How to choose
If you want to spend nothing right now, start with AIBIM AI or Runwall's free tier. If you're a solo developer or small team working with coding agents, Kastra, SafeClaw, or GnamiAI cover the basics for $19.99–$29/month. If you need per-seat sandboxing across a team, Runtime's $99/seat plan fits; for enterprise-wide agent-execution governance with many users, Oconee Runtime is built for that scale but costs the most.
FAQ
Is there a free alternative to Arcjet? Yes — AIBIM AI is free during its current beta, and Kastra, Runwall, GnamiAI, SafeClaw, and Runtime all offer free tiers or trials.
What's the cheapest paid alternative? Kastra's Pro plan at $19.99/developer/month is the cheapest stated paid price among these alternatives.
Which alternative is built for enterprise use? Oconee Runtime, starting at $750/month for 10 users, is explicitly positioned for enterprise-scale agent-execution controls.