Skylos

Overview

Skylos is an open-source static analysis tool for finding security regressions, exposed secrets, dead code, quality problems and mistakes introduced by AI. It suits teams that want local scans or CI checks, particularly Python teams already using Ruff, Pylint or Mypy. Its local-first CLI is a practical starting point; cloud workflows add collaboration and history, but uploading reports has privacy and retention trade-offs.

Key features

The CLI runs locally without an account, so teams can scan code and add CI checks without sending reports to Skylos. Analysis covers Python, JavaScript and TypeScript, Go, Java, Kotlin, PHP, Rust, Dart, C#, Shell and deployment configuration, with depth varying by language. That breadth is useful for mixed-language repositories, though teams should not assume equal coverage across every language.

The free VS Code extension adds inline diagnostics and optional AI verification through OpenAI or Anthropic API keys. GitHub pull request workflows, OIDC identity, and optional Slack and Discord notifications are cloud features. Local MCP tools cover analysis, security, quality and secret scanning; remediation uses credits, so it may add cost when teams use it.

A normal CLI scan stays on the user's machine. Data reaches Cloud when a report is uploaded, a cloud action is triggered or the public scan endpoint is used. Reports may contain findings, severity, rule identifiers, paths, line numbers, snippets, attribution and scan metadata, with provenance or defense evidence optional. Skylos describes role-based permissions, hashed project API keys, restricted GitHub OIDC uploads, bounded report ingestion and security headers. It does not claim SOC 2, ISO 27001 or CSA STAR certification.

Pricing

The free plan costs 0.00 USD per free. It combines local CLI scans without login with one cloud project, 10 stored scans and seven-day history, making it suitable for individual evaluation or light use rather than long-term team reporting.

Paid credit packs are one-time purchases, not recurring subscriptions: Starter costs 9.00 USD per once for 500 credits and 30 days of Pro access; Builder is 39.00 USD per once for 2,500 credits and 90 days; Team is 129.00 USD per once for 10,000 credits and 180 days; Scale is 499.00 USD per once for 50,000 credits and 365 days. Credits do not expire, but Pro access does, so buyers should distinguish the lasting credit balance from the time-limited access.

Workspace includes 10 projects, 500 stored scans per project and 90-day history. Enterprise has custom pricing, with 9,999 projects, 10,000 stored scans, 365-day history, unlimited credits, priority support and an SLA. The available packs suit intermittent or finite credit needs; teams requiring greater scale, retention or service commitments should consider Enterprise.

Platforms

Skylos supports API, extension, Linux, macOS, self-hosted, web and Windows environments. Its hybrid deployment model pairs local and CI use with optional cloud features, letting teams keep ordinary CLI scans local while opting into cloud workflows.

Who it's for

Skylos is best suited to developers and teams that want static analysis in local workflows, CI or VS Code, especially Python teams already using Ruff, Pylint or Mypy. Its cloud tier is a better fit when pull request workflows, notifications and stored scan history matter. Teams that require a named security certification should look elsewhere.

Pros and cons

• Pro: Local CLI scans need no account and stay on-device unless a cloud action or upload is used, giving teams a clear local workflow.
• Pro: Language coverage spans common application and deployment code, with CI, IDE and MCP entry points for different workflows.
• Pro: Credit purchases are one-time and credits do not expire, so occasional users need not commit to a recurring plan.
• Con: Cloud storage is capped by plan and history length, limiting long-term review on Free and Workspace.
• Con: Uploaded reports can include source snippets and file-level details, which may require review before a team enables cloud features.
• Con: Analysis depth varies by language, and Skylos does not claim SOC 2, ISO 27001 or CSA STAR certification.

Alternatives

For another free, open-source choice with CLI and platform components under Apache License 2.0, consider Horusec. Puma Scan offers a free Community plan and a 299.00 USD per year End User plan; it may suit readers comparing a paid annual license.

Semgrep Code is worth comparing for its free Code and Supply Chain edition, capped at 10 repositories, 10 contributors and 60 AI credits. For a dedicated open-source static analysis engine and CLI, OpenGrep is a free option.

Snyk Open Source focuses on software composition analysis; its free plan covers five projects. For teams seeking a paid web application and API testing product, Veracode DAST is another option. PVS-Studio and Black Duck Coverity are further alternatives for readers comparing static analysis tools.

See more tools in Static Application Security Testing Software.

Verdict

Choose Skylos if you want a local-first analyzer with CI and editor support, broad language coverage, and optional cloud workflows without a recurring credit-pack commitment. Its strongest case is keeping routine scans local while adding cloud features selectively. Look elsewhere if your team needs a recognized security certification, consistently deep analysis across every supported language, or cloud retention beyond the plan limits.