What Is Static Analysis?
Static analysis examines your source code without executing it, flagging bugs, risky patterns, and style issues before anything runs.
Tests run your code and observe behavior. Static analysis reads your code and reasons about it - catching issues like unused variables, null dereferences, or insecure patterns without needing to execute a single line.
Static vs dynamic analysis
Static analysis works on the code text or its compiled form, before execution. Dynamic analysis observes the program while it runs (tests, profilers, fuzzers). They catch different classes of problems and complement each other.
What it catches
- Likely bugs: null dereferences, unreachable code, type errors.
- Security issues: this is the basis of SAST.
- Style and maintainability: complexity, dead code, conventions.
A small example
A static analyzer flags if (x = 5) as a probable typo for ==, and a function that returns in some branches but not others, before any test runs. These are bugs a passing test suite might never trigger.
In the pipeline
Static analysis runs early and fast, often alongside linting, and gates the build before expensive tests run. Fast feedback here catches whole categories of bugs without ever starting the app.
Managing false positives
Static tools err toward flagging; some findings are not real bugs. Tune the rule set, suppress known-safe patterns with a documented reason, and track new findings on the diff so the backlog does not drown the signal.
Key takeaways
- Static analysis inspects code without running it.
- It complements dynamic analysis, catching different problem classes.
- It runs early and fast as a cheap gate before tests.