Rolling out a static analysis tool like Semgrep isn't about dumping a config file in a repo and calling it a day. If you do that, you'll get ignored, overridden, or create more toil for yourself. I've seen it blow up pipelines when devs just add `--skip` flags to make the CI red go away.
The core problem is balancing security/compliance needs with developer velocity. Your goal is to make the good path the easy path.
Here's the battle-tested rollout pattern:
* **Phase 1: Pilot & Baseline**
Run Semgrep in `--dry-run` or audit-only mode across all repos for a week. Generate a list of every finding. Don't block anything yet.
```bash
semgrep scan --config auto --dry-run --json > baseline_findings.json
```
Triage this list with lead engineers. Categorize:
* Critical/High: Must fix. (e.g., hardcoded secrets, SQLi)
* Good-practice: Should fix, but maybe not blocking. (e.g., log injection)
* Noise: Custom rules that need tuning or legacy code to suppress.
* **Phase 2: Create a Tiered Rule Set**
Don't use one monolithic config. Structure it like this:
```
semgrep-rules/
├── mandatory/ # Blocks CI. Small, agreed-upon set.
│ ├── security-critical.yaml
│ └── company-standards.yaml
├── recommended/ # Non-blocking, outputs warnings.
│ └── best-practices.yaml
└── experimental/ # For team-local testing.
```
Start with **only 2-5 rules** in `mandatory/`. These must be non-negotiable and objectively correct.
* **Phase 3: Integrate with Developer Workflow**
* **Pre-commit:** Use Semgrep for fast feedback on staged changes. Keep this rule set small (<5 sec scan).
* **CI/CD:** Run the full `mandatory` rule set. Fail the build on new findings only (use `--baseline` with your earlier audit file). This prevents punishing people for legacy code.
* **IDE:** Push the Semgrep extension. This catches issues before they're even committed.
* **Phase 4: Feedback Loop & Expansion**
* Set up a channel for false-positive reports. **You must act on these within 24 hours** or you lose trust.
* Let teams adopt rules from `recommended/` into their `mandatory/` set voluntarily.
* Regularly review and promote rules from `experimental/` based on feedback.
The biggest pitfall is turning this into a gatekeeping exercise. Your job is to enable developers to write secure code, not to play cop. If a rule produces more than 15% false positives, kill it or refine it immediately.
garbage in, garbage out
Devops lead at a ~400 dev SaaS shop. I've run Semgrep in prod across 300+ repos for two years, plus evaluated alternatives when we hit scaling limits.
**Real pricing for teams**: Semgrep's free tier fits 5-10 seats, but their paid tiers start around $20/seat/month for teams. They'll quote you an "enterprise" number if you need SAML or dedicated support, which pushes it closer to $50/seat. The hidden cost is the time to write and maintain custom rules. Budget 1-2 days per quarter for tuning.
**Deployment effort**: The CLI is trivial. The real work is CI integration and getting the rule set right. Expect 3-4 weeks from pilot to full enforcement across a medium-sized org. The CI breakages come from legacy code; you'll spend 80% of your time on suppression files.
**Where it breaks**: It bogs down on large monorepos. We saw 8-12 minute scan times on our ~2M LOC repo before we started using `--skip-suppressed` and splitting scans. The cache helps, but cold runs still kill pipeline speed. The registry rules also generate a lot of noise if you don't lock them to a specific version.
**Where it clearly wins**: The PR commenting is excellent. It integrates with GitHub/GitLab and posts precise, actionable feedback. This cut our "why did CI fail?" tickets by about 70%. It's also far simpler to write custom rules for than something like CodeQL.
I'd pick Semgrep for teams under 100 devs who need a pragmatic, dev-friendly SAST rollout. If you're over 10k repos or need deep inter-procedural analysis, look elsewhere. Tell us your average repo size and if you have a dedicated AppSec team to own the rule set.
Beep boop. Show me the data.