Arcjet
Arcjet is a developer-first, in-code security platform now extending into runtime protection for AI agents in production.
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Arcjet, founded in 2023 by David Mytton (former CEO of Server Density), builds a security-as-code platform that developers embed directly into application routes via SDK — providing bot detection, rate limiting, email validation, sensitive-data detection, and OWASP Top 10 web application firewall protections without a separate security appliance or gateway. It’s used across 500+ production applications and more than 1,000 developers, per company-reported figures.
In September 2026, Arcjet extended its product into “agent runtime security” — tracking what AI agents do once deployed in production, checking agent actions against policy before execution, and maintaining audit logs. Its $8.3M Series A (Oct 2025, $12M total) was backed by Plural, Andreessen Horowitz, Seedcamp, and notable devtools angels including former Twilio CEO Jeff Lawson.
Innovation Matrix Assessment
Extended from developer-first app security into AI-agent runtime enforcement, a timely but not wholly novel pivot.
Genuine production usage (500+ apps, 1,000+ developers reported) indicates real operational adoption.
Moderate raise ($8.3M) relative to peers; credible investor names but smaller round size.
In-code application security and bot detection is an established category; the AI-agent runtime layer is newer but incremental to existing product.
Usage figures are company-reported and not independently audited.
Application security is durable, but the AI-agent runtime feature's differentiation from competitors is still unproven.
Why CISOs Should Care
Lets engineering teams embed bot, abuse, and now AI-agent-action controls directly into application code rather than deploying a separate security gateway.
What Makes It Different
Ships as an SDK integrated at the code level rather than a network appliance or API gateway, extending that same in-code model to AI-agent runtime governance.
The Matrix Verdict
52/100 — INCREMENTAL INNOVATOR
A credible, developer-adopted application security vendor extending into AI-agent security; solid but not category-defining relative to dedicated AI-agent certification/insurance players.
Editorial Note: Claims vs. Verified Findings
Usage figures ("500+ production applications," "1,000+ developers") are company-stated and not independently verified.
Sources
- Arcjet Raises $8.3m — GlobeNewswire (Oct 8, 2025) — https://www.globenewswire.com/news-release/2025/10/08/3163261/0/en/Arcjet-Raises-8-3m-to-Tackle-Surge-in-AI-Powered-Cyberattacks-and-Malicious-Bots-with-In-Code-Defense.html
- Arcjet launches runtime security for AI agents — SiliconANGLE (Sept 17, 2026) — https://siliconangle.com/2026/09/17/exclusive-arcjet-launches-runtime-security-to-track-and-control-ai-agents-in-production/
- Arcjet — Crunchbase profile — https://www.crunchbase.com/organization/arcjet
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