Choose your path

No. Socrates comes with the built-in Beagle AI model that works out of the box on every tier with monthly token quotas. You can also bring your own API keys from OpenAI (GPT-5.5), Anthropic (Claude Opus 4.8, Sonnet 4.6), and any OpenAI-compatible endpoint (Together.ai, Groq, DeepSeek, vLLM, Ollama). We never charge for inference.

Diophantus (free) gives you up to 5 saved sessions, 1 LLM provider key, 1M Beagle tokens per month, standard teaching quality, a basic knowledge graph, and community support. All core features are included, such as LaTeX rendering, real-time streaming, tutor mode, exam and assessment, diagnostic questions, and the mistake book. No credit card needed. Just start learning immediately with Beagle.

Yes. Annual billing saves approximately 17%, effectively 2 months free. Riemann is $90/year (vs $108), Descartes is $190/year (vs $228), Euclid is $390/year (vs $468). You can choose monthly or annual during checkout. Annual plans can be cancelled anytime with pro-rated refunds.

Absolutely. Subscriptions are month-to-month with no long-term commitment. Upgrade instantly from your profile settings and the new features unlock immediately. Cancel any time. Your access continues through the end of the billing period. Downgrades take effect at the next billing cycle.

Euclid is our premium tier for power users and teams. Key differences: unlimited saved sessions vs 200, unlimited LLM provider keys vs 5, maximum teaching depth with full customization of the Socratic style, knowledge graph export (JSON/CSV), priority support with faster response times, and early access to new features before they ship to other tiers.

We don't offer refunds for partial months, but every subscription includes a 7-day free trial of the next tier up, so you can try before you commit. If you cancel during the trial period you won't be charged. Annual plans cancelled early may receive a pro-rated refund for remaining months.

Not yet, but we're working on it. If you're interested in team accounts, centralized billing, or managed deployments for your organization, email us at hello@topodrive.top and we'll keep you updated.

Currently we don't have a formal student discount program, but the free Diophantus tier includes all core teaching features. Many students use the free tier successfully with their own low-cost API keys. Email us at hello@topodrive.top if you have specific needs. We are flexible.