Caido

Caido is a web-security auditing toolkit focused on inspecting traffic and scaling manual testing. It suits pentesters, security engineers, and bug-bounty hunters who need filtering, repeatable workflows, and optional AI connections. The free tier is a credible way to start, while larger projects and teams will quickly need a paid plan.

Overview

Founded in 2021, Caido is presented by its bootstrapped, independent company as a lightweight toolkit for web, API, and mobile testing, with finding management included. Its center of gravity is a proxy-led workflow: capture traffic, search it, automate selected actions, and extend the environment when a standard feature is not enough.

Caido supports individual practitioners as well as collaborative deployments. The Penetration Testing Software category is the useful starting point for comparing it with scanners, operating-system toolkits, and reporting products.

Key features

Traffic interception and analysis

The proxy intercepts and monitors HTTP and WebSocket traffic, retaining history for intercepted requests and WebSocket messages. In practice, that gives an assessor a searchable record to revisit instead of relying only on what is visible in the moment. HTTPQL filtering searches requests and responses, which is particularly useful when an engagement generates more traffic than can be reviewed sequentially.

Automation and extensibility

Node-based workflows handle ad-hoc automation, while automated attacks can use custom payloads and placeholders. This is a good fit for testers who repeatedly modify requests or run structured variations, though the value depends on how much of an assessment can be expressed as a workflow rather than exploratory manual work. Community plugins and custom extensions provide an escape hatch for specialized needs; the Basic plan's three-plugin ceiling is a meaningful constraint for free users.

AI and programmatic access

Users can connect an existing LLM provider, including Anthropic, Google, OpenAI, and services reachable through OpenRouter. Caido also says AI agents can access it programmatically through the Client SDK. These options can add analysis or orchestration without locking a customer to one model vendor, but they require the user to bring an eligible provider relationship and to decide how that connection fits the engagement's security controls.

Data handling and trust

At registration, Caido collects an account name, email address, and user-agent. When cloud services are connected, it records instance IP addresses plus API-call actions and timestamps; it says instance data and in-app activity are not collected. A Trust Portal lets visitors request access to trust documents, which is a useful route for teams that need security documentation before adoption.

Pricing

Caido uses a freemium model. Basic costs free and is free forever. It includes two projects, seven workflows, three plugins, five filter presets, and one pipeline session at a time. That is enough for learning and small engagements, but the caps can force housekeeping for anyone juggling clients, automation recipes, or extension-heavy setups.

The Education Plan is free with a free one-year license for students and teachers at accredited institutions. It is the clearest route for classroom or individual study, but it is time-limited rather than a permanent free entitlement.

Individual has monthly or yearly billing and one user, with unlimited projects and workflows, AI Assistant, and nightly builds. Its displayed price is custom pricing, although the paid entry point is 20 /user/mo. This is the logical upgrade for a solo professional whose work outgrows Basic's caps. Team is billed per seat, monthly or yearly, and adds shared instances, reassignable licenses, and a dedicated support channel; its displayed price is also custom pricing. Enterprise uses custom pricing per seat and adds unlimited users, purchase orders, and custom integrations built on request. Basic and Individual receive public Discord support, while Team gets the dedicated channel.

Platforms

Caido is offered through web, Windows, macOS, Linux, API, and self-hosted options. That breadth helps teams fit it into mixed environments and makes self-hosting relevant where deployment control matters.

Who it's for

Choose Caido when your work revolves around manual web testing, traffic analysis, repeatable request manipulation, and optional AI-assisted workflows. It is especially well matched to pentesters, security engineers, and bug-bounty hunters who want one environment for web, API, and mobile assessments. It is less compelling if you need a permanently unrestricted free installation or a clearly published price for every paid tier before budgeting.

Pros and cons

Pros

• Strong traffic workflow: HTTP and WebSocket interception, history, and HTTPQL search support detailed investigation.
• Useful automation path: Node workflows, payloads, and placeholders reduce repetitive request work.
• Flexible AI access: Existing Anthropic, Google, OpenAI, and OpenRouter connections avoid a single-provider requirement.
• Extensible and deployable: Plugins, custom extensions, API access, and self-hosting suit varied environments.

Cons

• Basic is tightly capped: Two projects, seven workflows, three plugins, five presets, and one concurrent pipeline session limit sustained use.
• Most paid prices are not displayed: Budgeting beyond the stated 20 /user/mo starting point requires a quote.
• Team value starts with seats: Team is billed per seat, so collaborative growth increases the licensing commitment.
• AI is an add-on connection: Users must supply an existing LLM provider rather than receiving a universal model allowance.

Alternatives

Pentesterra is a better fit if you want a free DevGuard tier with one project, three scans per month, and CLI, IDE-plugin, and web-console access. Pick Dradis when open-source reporting and one-project-at-a-time community use matter more, or when a free trial is important. Kali Linux is the choice for a free, open-source security distribution rather than a focused proxy toolkit. OWASP Amass suits users seeking a free Apache-licensed framework. PenPeeper is a free option for personal or professional use under its restriction on resale and paid SaaS hosting. RedAmon is preferable for an MIT-licensed, Docker-based self-hosted stack. w3af is the alternative when a free open-source web-application scanner is the priority. Aircrack-ng is the choice for a free wireless-security software suite.

Verdict

Caido is a strong choice for professionals who want a focused proxy, powerful traffic search, workflow automation, and the option to connect AI and custom extensions. Its free Basic plan lowers the barrier to entry, but serious individual work can outgrow its caps and teams must obtain pricing for seat-based plans. Look elsewhere if you need a broad free distribution, a dedicated scanner, or fully transparent paid pricing before committing.