GateTest vs Semgrep
110 Modules vs Writing Rules in 2026
Semgrep is great at finding code that matches patterns you’ve written rules for. The gap is the bug nobody wrote a rule for yet — the SSRF in a handler that’s shaped differently, the race condition in a new ORM, the N+1 query introduced last Tuesday. GateTest uses Claude to read intent, not patterns.
The gap pattern-matching can’t close
Semgrep needs a rule to find a bug. These real bug classes ship every week — and no pattern covers them all:
Feature Comparison
| Feature | GateTest | Semgrep |
|---|---|---|
| Finds known vulnerability patterns (OWASP rules) | ✓ | ✓ |
| Semantic taint-flow analysis (multi-file) | ✓ | ✗ |
| AI reasoning — finds bugs no rule covers | ✓ | ✗ |
| Auto-fix PR (working code, not text substitution) | ✓ | ✗ |
| Dependency / SCA scanning | ✓ | ✓ |
| IaC security (Terraform, K8s, Dockerfile, CI) | ✓ | ✗ |
| Accessibility (WCAG 2.2 automated audit) | ✓ | ✗ |
| N+1 query detection | ✓ | ✗ |
| Datetime timezone bug detection | ✓ | ✗ |
| Money-float safety (parseFloat on currency) | ✓ | ✗ |
| Import cycle / circular dependency detection | ✓ | ✗ |
| PII-in-logs detection | ✓ | ✗ |
| Prompt injection / AI-app safety scanning | ✓ | ✗ |
| Mutation testing (via GitHub Action) | ✓ | ✗ |
| Cross-finding attack-chain correlation | ✓ | ✗ |
| Pay per scan (no rules to maintain) | ✓ | ✗ |
| PR / commit status integration | ✓ | ✓ |
Semgrep OSS covers pattern-matching SAST. Semgrep Code / Supply Chain / Secrets are separate paid products.
Why GateTest goes further
Reasoning vs. pattern matching
Semgrep matches code that looks like a known bad pattern. Claude reads your code and understands what it does — so it finds the SSRF that's shaped differently from any rule, the race condition in a new ORM, the N+1 in a loop structure nobody thought to write a rule for. The gap between 'matches pattern' and 'is actually dangerous' is where most real bugs live.
110 categories vs. one
Semgrep is a SAST engine — security and code quality. GateTest covers those plus accessibility (WCAG 2.2), performance, IaC security (Terraform, K8s, Dockerfile, CI pipelines), dependency hygiene, datetime bugs, money-float errors, import cycles, PII in logs, prompt injection, and more. One gate, one config, one bill.
Auto-fix PRs — not text substitutions
Semgrep's fix: patterns are text substitutions. GateTest's Scan + Fix tier ($199) uses Claude to write the actual fix logic — adds the SSRF validation guard, restructures the N+1 query into a batched lookup, fixes the datetime call with the correct timezone — then opens a pull request for your review. It's an engineer writing a fix, not a sed replacement.
No rules to maintain
Semgrep's value scales with your rule library. You either write custom rules (takes time) or use community rules (may be stale). GateTest's 110 modules are maintained for you — and Claude-driven reasoning improves with every scan through the recipe-distillation flywheel. Per-scan pricing means no maintenance overhead.
Frequently asked questions
How does GateTest differ from Semgrep?
Semgrep is a pattern-matching engine: it finds code that matches rules written in YAML. It's fast and configurable, and the community has written thousands of rules. The gap is anything nobody wrote a rule for. GateTest uses Claude to read your actual code and reason about what it does — it finds SSRF in an API handler it has never seen before, because Claude understands intent, not just structure. GateTest also runs 110 checks across categories Semgrep doesn't cover: accessibility, performance, N+1 queries, datetime bugs, money-float errors, import cycles, and infra (Dockerfile, K8s, Terraform, CI pipelines).
Does Semgrep have auto-fix?
Semgrep can apply fix: patterns defined in rules — automated text substitutions paired with the matched pattern. These work for simple, predictable transformations (rename this function call, add this import). They don't work for complex contextual fixes that require understanding the surrounding code. GateTest's Scan + Fix tier ($199) uses Claude to write the actual fix logic — adds the validation guard, restructures the N+1 loop, fixes the datetime call with the correct timezone — and opens a pull request for your review. The fix is code Claude wrote, not a text substitution.
What does Semgrep's free tier include vs. paid?
Semgrep OSS (open-source core) is free and powerful for security engineers who want to write or import custom rules. Semgrep Code (SAST), Supply Chain (SCA), and Secrets are commercial products with seat-based pricing. GateTest charges per scan: $99 for all 110 modules. No rules to write, no per-developer licensing, no annual contracts.
Does GateTest replace Semgrep rules I've already written?
GateTest is complementary if you have custom business-logic rules that are deeply specific to your codebase. For the standard vulnerability classes — SSRF, TLS bypass, PII in logs, N+1 queries, insecure cookies, ReDoS, import cycles — GateTest covers them out of the box with modules that reason about your specific code rather than matching patterns. The practical question is whether you spend time maintaining a rule library or buy 110 maintained checks per scan.
Does GateTest find injection vulnerabilities like Semgrep?
Yes. GateTest's SSRF module traces user-controlled input (req.body, req.query, req.params, event.body) through to HTTP client calls (fetch, axios, got, http.request, undici) and flags unvalidated paths. The taint flow is semantic, not pattern-matched — it understands variable aliasing and function returns, not just surface-level string proximity. The same reasoning applies to command injection surfaces. On the Forensic Scan tier ($399), Claude-driven cross-finding correlation can identify chains: 'missing input validation here combines with this overly-permissive IAM role to form a realistic SSRF → privilege-escalation path.'
How does GateTest handle false positives?
Pattern matchers like Semgrep tend to generate false positives when code matches a pattern structurally but is safe in context. GateTest modules are built with explicit suppression paths: test files downgrade severity, known-safe patterns (e.g. SSRF modules suppress on validateUrl/allowedHosts.includes guards, money-float suppresses when a decimal library is imported). Claude-driven findings on the Forensic Scan tier include reasoning, so you can see why a finding was flagged — not just a rule ID. The confidence-calibrator trainer tracks customer suppressions and flags rules with high dismissal rates as candidates for severity downgrades.
110 checks. No rules to write.
Security, quality, accessibility, performance, IaC, AI safety — in one scan. Claude finds what no pattern covers. One-time payment per scan.
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