SyncSEO probes five engines, all reachable from Settings → Engines:
- ChatGPT — GPT-4o family. Default enabled on every plan.
- Claude — Anthropic Claude Sonnet (and Opus on Premium-tier article generation). Default enabled on every plan.
- Perplexity — Sonar models, citation-grounded. Default enabled on every plan.
- Google Gemini — Growth plan and above.
- Google AI Overview — Growth plan and above.
Toggling engines
From Settings → Engines, check or uncheck per workspace. Empty selection means “use the system default” (the three free-plan engines). If your buyers don’t use Perplexity, turn it off and save credits — runs scale with engine count.
How probes are sent
Every engine receives the same probe variant for a given prompt (D1 cold, D2 regional, D3 niche-contextualised, D4 alternatives). We don’t hand-tune per engine; the same question goes to every engine and the comparison is apples-to-apples.
Why not all five always?
Cost. Each probe call costs a small amount through OpenRouter; a 200-prompt run × 5 engines = 1000 probes. We bake the cost into the credit price for plans that include all 5; Free / Starter stays at 3 to keep the per-credit math reasonable.