Verdict
Choose GTmetrix when
- Technical SEO matters to you. Strong technical performance and Core Web Vitals diagnostics, but not a full technical SEO crawler.
- Free tools matters to you. Provides meaningful free page testing, with paid limits for scale.
- Estimated customer scale matters to you. First-party figures indicate substantial adoption and enterprise reach.
- Value accessibility matters to you. Free entry point and relatively low-cost paid tiers provide accessible performance testing.
Verdict
Choose Semji when
- Content execution matters to you. Very strong AI-assisted drafting, optimization, brand voice, knowledge grounding, and reusable agents.
- AI-search / GEO matters to you. Dedicated GEO visibility monitoring, citation/source analysis, competitive benchmarking, and recommendations are documented.
- GEO readiness matters to you. GEO is integrated with planning, Atomic Content, AI Knowledge, and measurement rather than being only a report.
- Publishing workflow matters to you. Strong editorial planning, assignments, progress tracking, CMS/custom-solution recommendations, and Chrome integration; direct publishing is not clearly documented.
These tools solve different jobs. Scores are shown against each tool's own category, so the overall grades are not directly comparable. How grades work.
Read the full reviews: GTmetrix and Semji.