11 TypeScript Static Code Analysis Tools (2026)

Why TypeScript static analysis matters

TypeScript gives you a type system, and that catches a huge class of bugs before they ship. But a common misconception is that once a project compiles cleanly, it is safe. It is not. The compiler proves that your types line up - it does not prove your code is correct, secure, or maintainable.

tsc happily compiles a forgotten await that leaves a promise floating and an unhandled rejection waiting to crash your process. It compiles any values that quietly erase type safety as they propagate through your codebase. It does not know that a string flowing from req.query into a database call is a SQL injection, that a function has a cyclomatic complexity of 40, or that an entire module is dead code no one imports anymore. Strict mode helps, but strict mode is about type soundness, not about risky-but-valid patterns.

Static code analysis fills these gaps. The right tools for TypeScript fall into a few buckets: type-aware linters that use full type information to catch floating promises and unsafe any, dead-code and coverage tools that keep the codebase lean, security SAST scanners that trace tainted data, and platforms or AI reviewers that roll quality and review into CI. This guide covers the 11 tools that matter in 2026 and how to combine them.

Comparison table

Tool	Type	Pricing	Best for
tsc —noEmit (strict)	Type checker	Free (OSS)	The non-negotiable baseline
typescript-eslint	Type-aware linter	Free (OSS)	Floating promises, unsafe any
Biome	Linter + formatter	Free (OSS)	Fast lint and format in one tool
Knip / ts-prune	Dead-code finder	Free (OSS)	Unused files, exports, deps
type-coverage	Type metrics	Free (OSS)	Measuring any leakage
SonarQube	Quality platform	Community free, paid from ~$13/mo	Quality gates, 300+ TS rules
DeepSource	Quality platform	Free tier, ~$24/user/mo	Autofix and CI quality checks
Codacy	Quality platform	Free tier, ~$15/user/mo	Multi-language org dashboards
Semgrep	Security SAST	OSS free, paid from ~$35/contrib/mo	Custom TS security rules
Snyk Code	Security SAST	Limited free, ~$25/dev/mo	Cross-file taint analysis
CodeRabbit	AI reviewer	Free for OSS, ~$24/user/mo	Contextual PR review
CodeAnt AI	AI reviewer + SAST	Paid, contact sales	Combined quality and security
Sourcery	AI refactoring reviewer	Free tier, paid plans	Refactor suggestions in PRs

Type-aware linters and compiler tooling

These are the foundation. They run locally and in CI, they are free, and they catch the majority of everyday TypeScript issues before any platform or AI tool sees the code.

1. tsc —noEmit with strict mode

The TypeScript compiler is itself the most important static analysis tool you have. Running tsc --noEmit type-checks the project without producing output, and turning on strict activates the full suite of soundness checks: strictNullChecks, noImplicitAny, strictFunctionTypes, strictBindCallApply, and more. Adding noUncheckedIndexedAccess, noUnusedLocals, noUnusedParameters, and exactOptionalPropertyTypes pushes the floor even higher.

No other tool can replace this, because it performs full-program type inference that linters and AI reviewers do not attempt. If you do one thing for TypeScript code quality, enable strict mode and gate CI on a clean tsc run.

Key features: Full type inference, null safety, unused-symbol detection, no extra install. Pricing: Free, bundled with TypeScript. When to use it: Always, on every project, as the CI baseline before anything else runs.

2. typescript-eslint

The standard ESLint rules look at syntax only. typescript-eslint is the official plugin and parser that gives ESLint access to your TypeScript type information, which unlocks a category of rules the compiler does not enforce. With type-checked rules enabled, it flags no-floating-promises (an async call you forgot to await), no-misused-promises, await-thenable, and the no-unsafe-* family that catches any values leaking into assignments, calls, member access, and returns.

These are exactly the dangerous-but-valid patterns tsc lets through. Enabling the strictTypeChecked config is the single biggest linting upgrade most TypeScript teams can make. The tradeoff is speed: type-aware rules require type-checking each file, so lint runs are slower than syntax-only linting.

Key features: no-floating-promises, no-unsafe-assignment, no-explicit-any, strict-boolean-expressions, no-non-null-assertion. Pricing: Free and open source. When to use it: Every TypeScript project. Run the type-checked config in CI even if you keep a lighter config for editor speed.

3. Biome

Biome is a Rust-based toolchain that combines a linter and a formatter, with native TypeScript and JSX support and no plugin setup required. Its headline feature is speed - it runs roughly 20-100x faster than ESLint, which makes it attractive for large monorepos and pre-commit hooks where lint time is painful.

The caveat for TypeScript specifically is that Biome does not yet perform full type-aware analysis. It cannot replicate no-floating-promises or the no-unsafe-* rules that depend on type information. The common pattern in 2026 is to use Biome for formatting and fast syntactic linting and keep typescript-eslint only for the type-checked rules Biome cannot match.

Key features: Combined lint and format, native TS/JSX, extremely fast, single binary. Pricing: Free and open source. When to use it: New projects wanting one fast tool, or as the formatter and fast-lint layer alongside typescript-eslint.

4. Knip and ts-prune (dead-code detection)

The TypeScript compiler analyzes one file at a time, so it can flag an unused local but never an unused export or a whole module nobody imports. Knip closes that gap. It scans an entire TypeScript project to find unused files, exports, types, and dependencies, which keeps bundles small and refactors honest. ts-prune was the earlier tool for finding unused exports, but it is now largely superseded by Knip’s broader analysis.

Dead code is a quiet tax on TypeScript projects: it slows builds, inflates bundles, and misleads readers into thinking abandoned code is still live. Running Knip in CI prevents that accumulation.

Key features: Unused files, exports, types, dependencies, and devDependencies across the whole project. Pricing: Free and open source. When to use it: Any project past a few thousand lines, especially monorepos and libraries with many entry points.

5. type-coverage

type-coverage measures what percentage of your codebase is actually typed versus implicitly or explicitly any. A project can compile cleanly while still being riddled with any escapes that silently disable type checking. type-coverage gives you a single number to track and a CI threshold to enforce, so coverage can only go up over time.

It pairs well with a gradual migration strategy. Set the current percentage as a floor, fail CI on regressions, and ratchet the target upward as you eliminate any.

Key features: Per-file and total type-coverage percentage, configurable minimum threshold, strict mode for counting. Pricing: Free and open source. When to use it: JavaScript-to-TypeScript migrations and any team trying to drive down any usage.

Quality platforms

Platforms roll many checks - rules, duplication, complexity, coverage, and security - into a hosted dashboard with historical trends and quality gates. They trade some depth in any single area for unified reporting across a whole organization.

6. SonarQube

SonarQube ships 300+ rules for TypeScript covering bugs, code smells, security hotspots, and maintainability, and its defining feature is the quality gate: a configurable pass/fail threshold on new code that blocks merges when standards slip. It tracks complexity, duplication, and coverage over time, and the “clean as you code” model focuses enforcement on changed lines so legacy debt does not stall delivery.

The free Community Edition runs the TypeScript analyzer fully, and SonarCloud offers a hosted option that is free for public repositories. It is the most widely adopted quality platform in enterprises that need auditable gates.

Key features: 300+ TS rules, quality gates on new code, complexity and duplication metrics, OWASP coverage. Pricing: Community Edition free; paid editions and SonarCloud start at approximately $13/month and scale by lines of code. When to use it: Teams that want enforceable quality gates and long-term trend tracking across many repos.

7. DeepSource

DeepSource is a hosted code-quality platform with native TypeScript support that runs on every pull request and surfaces bugs, anti-patterns, performance issues, and style problems. Its standout is Autofix - for many issue classes it generates a fix you can apply with one click directly from the PR, which lowers the cost of acting on findings.

It also tracks code coverage and lets you set quality thresholds that block merges. The individual tier is free, which makes it easy to trial on a single repo before rolling out.

Key features: TS-native analyzers, one-click Autofix, coverage tracking, PR-level quality checks. Pricing: Free individual tier; team plans around $24/user/month. When to use it: Teams that want analysis plus automated fixes wired into the PR flow.

8. Codacy

Codacy aggregates static analysis across many languages into one dashboard, wrapping tools like ESLint and others behind a unified grade and policy layer. For TypeScript it analyzes .ts and .tsx natively, tracks complexity and duplication, and lets you enforce per-repository quality policies and coverage gates from a central place.

Its strength is organizational visibility - an engineering lead can see quality across dozens of repos at a glance, with consistent standards applied everywhere. It is a good fit when TypeScript is one of several languages in your stack.

Key features: Multi-language dashboards, quality policies, coverage gates, complexity and duplication tracking. Pricing: Free tier available; paid plans start at approximately $15/user/month. When to use it: Organizations standardizing quality across many repos and languages, not just TypeScript.

Security SAST for TypeScript

The platforms above touch security, but dedicated SAST tools go deeper, tracing how untrusted data flows from source to sink and shipping rule libraries tuned for real vulnerability classes.

9. Semgrep

Semgrep is a fast, pattern-based SAST scanner with maintained TypeScript rulesets covering XSS, injection, hardcoded secrets, insecure cookie and JWT handling, and dangerous configuration. Its biggest advantage is custom rules: the pattern syntax looks like the code you are matching, so a team can codify its own TypeScript security and anti-pattern rules in a few lines and enforce them in CI.

Scans are quick, and the open-source CLI is free, with a hosted platform layering on dashboards, triage, and managed rule policies. For teams that want security rules they fully control, Semgrep is the most flexible option.

Key features: TS security rulesets, fast scans, easy custom rules, CI and pre-commit integration. Pricing: Open-source CLI free; team platform starts at approximately $35/contributor/month. When to use it: Teams that want fast SAST plus the ability to write and enforce their own TypeScript rules.

10. Snyk Code

Snyk Code performs cross-file taint analysis tuned for Node.js and TypeScript. Rather than matching local patterns, it follows data flows across functions and modules to detect injection, path traversal, prototype pollution, and insecure deserialization where untrusted input actually reaches a dangerous sink. That dataflow approach cuts down on noisy findings that are not really exploitable.

It plugs into IDEs, the CLI, and CI, and pairs naturally with Snyk’s dependency scanning so you cover both your TypeScript code and the npm packages it imports.

Key features: Cross-file taint and dataflow analysis, Node.js/TS tuning, IDE and CI integration, fix guidance. Pricing: Limited free tier; paid plans around $25/developer/month. When to use it: Node.js and TypeScript teams that want deep, low-noise dataflow security analysis.

AI code reviewers

AI reviewers use large language models to read diffs in context and leave review comments. For TypeScript they understand types, interfaces, and framework patterns, catching logic and design issues that rule-based tools miss.

11. CodeRabbit, CodeAnt AI, and Sourcery

CodeRabbit reviews pull requests with awareness of TypeScript types and surrounding context, generating summaries and line-level comments that flag logic errors, missing edge cases, and questionable patterns. It complements - rather than replaces - your linters and SAST, catching the semantic issues static rules cannot express. It is free for open-source repositories.

CodeAnt AI combines AI review with built-in SAST and quality checks, so a single PR pass covers security findings, code smells, and AI commentary together. It targets teams that want one tool spanning quality and security rather than a stack of separate ones.

Sourcery focuses on refactoring. It reads TypeScript diffs and suggests cleaner, simpler implementations - extracting functions, simplifying conditionals, and reducing complexity - directly as PR feedback, which makes it a useful complement to correctness-focused reviewers.

Key features: Type-aware PR review, summaries, security and refactor suggestions depending on the tool. Pricing: CodeRabbit free for OSS and ~$24/user/month otherwise; Sourcery has a free tier; CodeAnt AI is paid, contact sales. When to use it: Catching semantic, design, and refactor issues that linters and SAST cannot express.

How to choose the right setup

There is no single best tool - the right TypeScript stack depends on your project type and team size. The constant in every setup is the free foundation: tsc strict mode plus typescript-eslint type-checked rules. Everything else layers on top of that.

• Solo developer or side project: tsc strict, typescript-eslint, Biome for formatting, and Knip to keep it clean. All free, all local.
• Open-source library: Add type-coverage to drive down any, Knip to catch unused exports across entry points, and CodeRabbit’s free OSS tier for PR review.
• Funded startup or product team: The free foundation plus DeepSource or SonarCloud for quality gates, Semgrep for security, and CodeRabbit for AI review on every PR.
• Enterprise: SonarQube or Codacy for org-wide gates and audit trails, Snyk Code for deep dataflow security, plus the compiler-and-linter baseline enforced in CI everywhere.

Recommended stacks by team size:

Team size	Type safety	Quality	Security	AI review
Solo	tsc strict + typescript-eslint	Biome + Knip	Semgrep OSS	CodeRabbit (OSS)
Startup	tsc strict + typescript-eslint	DeepSource or SonarCloud	Semgrep	CodeRabbit
Enterprise	tsc strict + typescript-eslint	SonarQube or Codacy	Snyk Code + Semgrep	CodeAnt AI or CodeRabbit

The pattern is consistent: start with the free compiler-and-linter baseline that every project needs, then add a quality platform when you want gates and trends, a SAST tool when security matters, and an AI reviewer when you want semantic feedback no rule engine can provide.

Further reading

• JavaScript code analysis tools
• Best SAST tools in 2026
• Best AI code review tools
• Best code quality tools
• Static code analysis tools - a complete guide