Caido

Overview

Caido is a web security auditing toolkit for examining traffic and scaling manual testing. It is best suited to pentesters, security engineers, and bug bounty hunters who want filtering, workflow automation, and optional AI connections in one toolkit. Its free tier makes it approachable, though the tight project and workflow caps and the lack of published prices for most paid plans make it harder to judge the cost of growing into it.

It supports web, API, and mobile testing and finding management. Caido was founded in 2021 and describes itself as bootstrapped and independent. See our Penetration Testing Software list for more tools in the category.

Key features

Traffic inspection and search

Caido’s proxy intercepts and monitors HTTP and WebSocket traffic, with history for intercepted traffic and WebSocket messages. That gives testers a record to inspect during an assessment rather than limiting review to live requests. HTTPQL filtering searches requests and responses, a useful complement when traffic volumes make manual browsing cumbersome.

Workflows, extensions, and AI

Node-based workflows support ad-hoc automation, and automated attacks can use custom payloads and placeholders. This suits testers who want to repeat or adapt tasks without turning every step into a manual sequence. Community plugins and custom extensions add room to extend the toolkit, although Basic limits users to three plugins.

Users can connect an existing LLM provider, including Anthropic, Google, OpenAI, and providers available through OpenRouter. AI agents can also access Caido programmatically through its Client SDK. This approach lets users bring an existing provider, but the plan descriptions do not establish what AI usage costs or quotas apply.

Data and trust

At registration, Caido collects account name, email, and user-agent. When users connect to cloud services, it collects instance IP addresses and API-call actions and timestamps; it says it does not collect instance data or in-app activity. A Trust Portal lets visitors request access to trust documents, rather than providing direct access to them.

Pricing

Caido is freemium, with paid access from $20/user/mo. There is no free trial. Basic is free forever and includes two projects, seven workflows, three plugins, five filter presets, and one pipeline session at a time. Those caps make it a reasonable starting point for individual evaluation, but a meaningful constraint for parallel work or users who need more room to organize assessments.

The free Education Plan is a one-year license for students and teachers at accredited institutions. It is time-limited, unlike Basic, and its stated eligibility narrows its relevance to that group.

Individual offers unlimited projects and workflows, AI Assistant, nightly builds, and one user, with monthly or yearly billing. The price is custom pricing. It is the more natural fit for a solo user who outgrows Basic’s project and workflow caps, but the absent price prevents a direct cost comparison with Basic or the advertised paid starting point.

Team is priced per seat with monthly or yearly billing and includes shared instances, reassignable licenses, and a dedicated support channel. It fits teams that need shared work and license flexibility, though the custom pricing means seat costs cannot be assessed in advance. Enterprise uses custom pricing per seat and adds unlimited users, purchase orders, and custom integrations built on request; it is aimed at organizations needing those purchasing or integration arrangements rather than a small team. Basic and Individual receive public Discord support.

Platforms

Caido supports API, Linux, macOS, self-hosted, web, and Windows. The combination of desktop, web, and self-hosted options gives deployment flexibility across common environments.

Who it's for

Caido is a good fit for pentesters, security engineers, and bug bounty hunters who want to inspect HTTP and WebSocket traffic, search requests and responses, and automate parts of manual testing. The free plan is useful for trying its core approach, but its caps make it less suited to sustained work across several projects or workflows. Buyers who need predictable paid pricing should compare carefully before committing.

Pros and cons

• Pros: Traffic history covers HTTP and WebSocket messages, while HTTPQL provides request and response filtering.
• Pros: Node-based workflows, custom payloads, plugins, and connections to existing LLM providers offer several ways to adapt testing work.
• Pros: Multiple platform options include self-hosted deployment.
• Cons: Basic caps users at two projects, seven workflows, three plugins, five filter presets, and one pipeline session at a time.
• Cons: Individual and Team prices are not published, so readers cannot readily compare their costs; there is also no free trial.
• Cons: The Education Plan lasts one year, so it is not a perpetual free option for eligible users.

Alternatives

Pick Dradis if you want a freemium option whose Community Edition is open source, free forever, and limited to one project at a time, with community forum support; it also offers a free trial.

Pentesterra is another freemium option; its DevGuard Free plan includes one project, three scans per month, a CLI, IDE plugin, web console, and community support.

Choose RedAmon if an open-source, self-hosted Docker stack with no license fee for commercial or personal use is the priority.

Aircrack-ng is a free software suite with no license fee for users who want that alternative.

Faraday is a freemium alternative with an Always On plan and a Pentest on Demand plan; the latter excludes vertical modules.

OWASP ZAP is free and open source, and may suit readers who prefer a project anyone can contribute to.

Kali Linux is another free option, available for Linux, Windows, macOS, and Android.

Revelion offers a PAYG Free plan with 10,000 starting credits and no monthly commitment; MSP Basic costs £99 a month, with annual billing roughly 17% below monthly.

Verdict

Choose Caido if you are a security tester who values traffic history, searchable requests and responses, and configurable workflows, with the option to connect an existing LLM provider. Its free Basic plan is a useful entry point, but its caps are restrictive for broader work, and the unpublished prices for Individual and Team leave the cost of scaling unclear. If those limits or pricing uncertainty are decisive, compare alternatives before moving beyond the free tier.