Compare/Veto vs Arcjet

Veto vs Arcjet

Arcjet is a security SDK for web applications. It blocks bots, rate-limits abusive traffic, validates emails, and shields signup flows. Veto is a runtime authorization SDK for AI agents. It intercepts tool calls and decides whether the agent is allowed to execute them. These are very different problems: protecting inbound traffic to your app vs controlling outbound actions from your agent. They can live in the same codebase without overlap.

Operational assessment

Arcjet is one of the cleaner developer security SDKs to appear in the last few years, Next.js-native, fast, and focused on real abuse problems (bots, bursts, fake signups). If you run a Next.js app and need bot defense, Arcjet is a fit. None of that overlaps with what Veto does. Veto solves a different problem entirely: when your AI agent decides to call issue_refund(amount=50000), do you let it run? You almost certainly want both products in a production AI app. They protect opposite directions of traffic.

What each product does

Arcjet

A developer security SDK for request-level protection, bot defense, and rate limiting. SDK path for Next.js, Node, Bun, and Deno. Code-first configuration in TypeScript, with decisions made at the edge.

Core capability:

Bot detection, rate limiting, signup-form protection, email validation, sensitive data shielding. Returns edge request decisions so your app can deny or challenge abusive inbound traffic before doing any work.

  • Bot fingerprinting and detection
  • Rate limiting with multiple algorithms
  • Email validation for signup flows
  • Sensitive-data filter for incoming payloads
  • TypeScript-native config and decision API

Veto

An open-source SDK that intercepts AI agent tool calls and evaluates them against YAML policies before execution. Sits inside the agent process, decides allow, deny, or escalate per call.

Core capability:

Policy-driven authorization on each tool invocation. Considers tool name, arguments, user, and context. Review-required actions can be routed to a human for approval before the call resumes.

  • Tool-call interception and authorization
  • Human review approval queues
  • Declarative YAML policies in version control
  • SDK and framework integrations
  • Apache-2.0 SDK, self-hostable engine

Feature comparison

These are not competing products. The table mostly shows that each one covers what the other does not.

CapabilityVetoArcjet
Tool-call authorization
Human approval workflows
YAML policy engine
Bot detection
Inbound rate limiting by IP
Email validation
Signup-form abuse protection
Per-tool rate limits for agents
Per-decision record
TypeScript SDK
Python preview
Open-source core

Choose by control direction: inbound or outbound

Imagine your application as a box with arrows on both sides. Inbound traffic from users. Outbound traffic from your agent. Different security tools live on different arrows.

Inbound (Arcjet's home)

Bots scraping your site, attackers brute-forcing logins, abusive signups, fake email addresses, a spike of traffic from one IP. Arcjet's checks fire on requests entering your app. Decisions are by IP, fingerprint, header, rate.

Outbound from the agent (Veto's home)

Your agent has decided to fire a tool. delete_customer, send_money, push_to_main. Veto's checks fire on those calls. Decisions are by tool, argument values, user role, and policy.

Both arrows matter

A production AI app needs Arcjet (or equivalent) on inbound to keep junk traffic out. It needs Veto on outbound to keep the agent inside policy. Treating these as alternatives misses the shape of the problem.

Pricing

Veto

Open Source runs locally. Core adds shared approvals, decision records, export, and retention. See the pricing page for price, retention, and action limits.

Arcjet

Arcjet pricing and package shape can change. Verify the current public tier, quotas, and enterprise terms on the Arcjet site.

Decision framework

Choose Veto when

  • You build AI agents that execute tool calls
  • You need allow, deny, or approve decisions per call
  • Sensitive operations must route to a human before execution
  • You want per-decision records logs
  • You build against LangChain, MCP, or other agent frameworks

Choose Arcjet when

  • You run a Next.js, Node, or Bun app and need inbound abuse defense
  • Bot traffic, signup spam, or scraping are real problems
  • You need email validation and rate limiting in one SDK
  • You want code-first config rather than a workspace rules engine
  • You need edge request decisions before application work

Frequently asked questions

Is Arcjet an AI security product?
Arcjet is a developer security SDK for web apps. Its primary problems are bot detection, rate limiting, signup abuse, and email validation. It has some AI-specific abuse features (detection of AI scraping bots, abuse signals for AI-generated traffic) but its core job is protecting your web application from incoming requests. Veto protects your AI agent's outgoing tool calls, a different control point.
Can Arcjet stop my AI agent from doing something destructive?
Not at the same boundary. Arcjet inspects HTTP traffic at the application boundary, mostly inbound. It is not the policy layer for the tool call your agent is about to execute. If your agent decides to issue a large refund or delete a customer record, the control point needs to sit on that tool path. Veto runs inside the agent path and blocks or escalates the call before execution.
Do Veto and Arcjet overlap at all?
Almost not at all. Arcjet is on the inbound web side, shape, throttle, and validate traffic coming into your app. Veto is on the outbound agent side -- gate the function calls your agent emits. They can live in the same codebase comfortably without overlap, similar to how a WAF and an internal authorization library coexist.
What about rate limiting agent tool calls?
Veto policies can express rate limits per user, per tool, per agent, "this agent may not call charge_card more than five times per hour." Arcjet's rate limiting is for inbound web requests by IP, user, or API key. They look superficially similar but apply to opposite directions of traffic.

Related comparisons

Veto vs Cloudflare AI Firewall

Edge vs application layer

Veto vs Vercel AI Gateway

LLM routing vs action control

Veto vs Multifactor

Account sharing vs authorization

Going deeper: AI agent authorization, LangChain integration, Blog: the authorization gap.

Arcjet keeps abuse out. Veto keeps the agent in line.

Sign upRead docsBook a call