Arcjet vs Pillar Security

How do Arcjet and Pillar Security differ?

Pillar Security is an AI security platform that covers the AI lifecycle: Pillar discovers AI assets across code, platforms, and endpoints, red teams agents, applies runtime guardrails to prompts and responses, and maps findings to compliance frameworks. Arcjet is an AI agent runtime security platform that enforces one policy in the path of each action: inside your code for custom agents, and in the hooks that Claude Code, GitHub Copilot, Cursor, and OpenAI Codex already fire, with no gateway to route through. The key difference is what each product checks at runtime. Pillar's published integrations inspect the content of prompts and responses, and Arcjet decides the action itself – the command, the path, or the destination – before it runs. Choose Pillar if you want discovery, posture, red teaming, and guardrails from one vendor across the AI your organization builds. Choose Arcjet if you want an allow or deny decision before each coding-agent or custom-agent action, with policies your engineers can test and publish themselves.

Arcjet publishes this comparison. Competitor details come from Pillar Security's public documentation, reviewed on September 25, 2026. Pillar's product documentation requires an access code, so this comparison relies on Pillar's public website, its published integrations, and announcements. Products change, so check the linked sources before you decide.

Arcjet and Pillar Security at a glance

Arcjet decides agent actions in the agent's hook and in your code, and Pillar Security covers discovery, red teaming, runtime guardrails, and governance across the AI lifecycle. The following table compares the two products across 13 areas.

What is Pillar Security?

Pillar Security is an AI security platform that describes itself as "one platform to discover, test, secure and govern every AI agent across your organization." Dor Sarig and Ziv Karliner founded Pillar, and the company raised a $9 million seed round led by Shield Capital, with Golden Ventures and Ground Up Ventures, on April 16, 2025.

On September 16, 2026, Pillar announced that Gartner named it a Pioneer in the 2026 Emerging Market Quadrant for AI Application Security. Pillar's research team publishes vulnerability research on coding agents and MCP servers, including Gemini CLI and the Dolt and Grafana MCP servers.

The Pillar platform has four modules. The following table summarizes what Pillar's pages say about each module:

Pillar says its runtime protection "can alert on or block a dangerous action before it runs." Pillar's solutions page describes two delivery points. For agentic endpoints, Pillar deploys through MDM to "discover every AI coding agent, MCP server, plugin, and configuration across your fleet," and at runtime monitors "every prompt, tool call, and command to detect prompt injection, tool poisoning, and data exfiltration." For AI gateways, Pillar inspects every prompt and response.

One published Pillar integration is the LiteLLM guardrail, which calls Pillar's API before and after the model call for prompt injection, jailbreaks, PII and PCI data, secrets, and content moderation. Pillar also publishes a Python SDK, at version 1.1.5 as of October 29, 2025. Pillar's homepage offers deployment in your own VPC and a demo, and doesn't publish pricing.

What is Arcjet?

Arcjet is an AI agent runtime security platform. Arcjet discovers the agents running in your organization, enforces policy across every action, prompt, and tool call, and keeps the evidence to prove what happened. Arcjet enforces in the path of the action, in code or in the agent's hook, not on the network.

For coding agents, Arcjet uses the hooks that Claude Code, GitHub Copilot, Cursor, and OpenAI Codex already fire, with no SDK and no code change. You install the hook configuration through managed settings, MDM, or an organization lock, so developers can't remove it without administrator access. One policy applies across all four agents and decides before the action runs, on a tool call, a prompt, or a model switch.

Arcjet ships 12 starter policies for coding agents, covering destructive commands, history rewrites, protected paths, credential access, piped installers, MCP allowlists, egress allowlists, destination threats, model allowlists, sensitive information, prompt injection, and npm publishing. Evaluation runs at the edge in over 300 data centers, and a hook adds one request of latency, typically a few tens of milliseconds.

For custom agents and applications, the JavaScript, TypeScript, Python, and Go SDKs provide guard() for tool calls, queues, MCP handlers, and any action that has no HTTP request, and protect() for HTTP routes. Integrations cover 15 frameworks: the Claude Agent SDK, Claude Managed Agents, Cloudflare Think, CrewAI, Genkit, Google ADK, LangChain, LangGraph, Mastra, OpenAI Agents, Strands Agents, TanStack AI, Vercel AI SDK, Vercel Eve, and Microsoft Agent Framework for Go.

Guard policies are centrally managed and written in Rego (OPA) or with a builder. You publish them from the Arcjet Console or the MCP server, run them in dry run before they go live, and changes take effect in real time. Detectors cover prompt injection, sensitive information, destination threats, token and spend budgets, and rate limits. The same SDK covers bot detection, rate limiting, Shield WAF, and email validation.

The Arcjet Console records every decision and session. You can export decisions to Datadog, Splunk, SentinelOne, Panther, and Amazon S3 on the Enterprise plan. Arcjet holds a SOC 2 Type 2 report, available at trust.arcjet.com.

Arcjet publishes its pricing: Individual at $25 per month, Startup at $299 per month, and custom Enterprise pricing, with a 15-day trial. Agent usage costs $50 per million agent requests.

Key differences between Arcjet and Pillar Security

Arcjet differs from Pillar Security in four ways: what each product checks at runtime, where the check runs, how policies are written, and which lifecycle stages Pillar covers that Arcjet doesn't. The following sections cover each one.

Deciding the action, not only inspecting the text

Pillar's published runtime integrations center on content: a guardrail that inspects prompts and responses at an AI gateway or through its API, and endpoint monitoring that detects injection, tool poisoning, and exfiltration. A content guardrail catches unsafe text wherever that text passes the inspection point.

Arcjet decides the action itself. An Arcjet coding-agent policy reads the tool, the command, the path, the MCP server, and the destination host, and answers allow or deny before the tool runs. A policy can deny rm -rf on a build directory, a write to .github/workflows, a read of a cloud credentials file, or a request to a host with a poor reputation, even when the prompt that led there looks harmless. For more information about why action-level checks matter, see secure AI agents in production.

No gateway to route through

A gateway guardrail sees the traffic that passes through the gateway. Arcjet runs in the agent's hook and in your code, so a tool call is decided where it executes, whether or not it involves a model call that crosses a gateway. Coding agents on developer machines, background jobs, and MCP handlers use the same Arcjet policy.

Policies engineers can read and test

Arcjet policies are Rego or builder rules. Each Arcjet policy carries its own tests, runs in dry run before it goes live, and can be generated from an English description and then reviewed. Engineers can read a policy in a code review, and a security team can publish a change without an application deploy. Pillar's public materials don't describe its policy format.

Where Pillar goes further

Pillar covers parts of the AI lifecycle that Arcjet doesn't. Pillar scans repositories for AI assets, assesses posture and supply chain risk, runs automated red teaming, and produces compliance reports for four frameworks. Pillar's guardrails also document system prompt protection, taint analysis for data egress, and deployment in your own VPC.

When to choose Pillar Security

Choose Pillar Security when you want one vendor across the AI lifecycle, from repository discovery to red teaming to runtime guardrails. Pillar fits when any of the following apply:

• You want discovery, posture management, red teaming, and runtime guardrails from one vendor.
• You need an inventory of the AI models, agents, and MCP servers in your code repositories.
• You want guardrails at an AI gateway you already run, such as LiteLLM.
• Compliance mapping to frameworks such as the EU AI Act and ISO 42001 is a primary requirement.
• You need the platform deployed in your own VPC.

When to choose Arcjet

Choose Arcjet when you need an allow or deny decision on the agent's action before it runs, not only a check on the text. Arcjet fits when any of the following apply:

• You want to enforce one policy on Claude Code, GitHub Copilot, Cursor, and OpenAI Codex before each tool call runs.
• You build custom agents in JavaScript, TypeScript, Python, or Go and want the decision in your code, next to the tool.
• You want policies in Rego with tests and dry run, published without an application deploy.
• You want to check the destination an agent is about to contact against threat intelligence.
• You also need bot detection, rate limiting, and WAF rules for the application that hosts the agent.
• You want to read the documentation and start without a sales call.

For more information about the coding-agent threat model, see coding agent security.

Can you use Pillar Security and Arcjet together?

Yes, Pillar Security and Arcjet can run side by side. Pillar can find the AI assets in your repositories, test them with red teaming, and screen content at your AI gateway. Arcjet can decide the actions: shell commands, file writes, credential reads, MCP servers, and network destinations in coding agents, and the tool calls inside your own agents. Red-team findings from Pillar can become Arcjet policies that you test in dry run before they go live.

What are the alternatives to Pillar Security?

Pillar Security alternatives include content detectors, enterprise AI control planes, and tools that enforce policy on agent actions directly. The following products are common alternatives to Pillar Security, depending on which part of Pillar you need:

• Arcjet enforces one policy on coding agents through their native hooks and on custom agents through SDKs, with public documentation and self-serve pricing.
• Lakera, part of Check Point, is a prompt and response detector with a hosted API.
• Onyx Security positions itself as a secure AI control plane with discovery, inline inspection, red teaming, and an AI gateway.
• Runlayer is an AI enablement and control platform built around an MCP gateway, endpoint discovery, and hooks.

For the difference between posture products and runtime enforcement, see AI security posture management versus runtime security.