AI tool comparison
Cal.diy vs Sup AI
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Productivity
Cal.diy
Cal.com, forked — all enterprise code removed, MIT licensed
50%
Panel ship
—
Community
Paid
Entry
Cal.diy is a community-maintained fork of Cal.com with all enterprise and commercial code stripped out — no Teams, no Organizations, no Insights, no SSO/SAML, and crucially, no license key required. Everything works out of the box under a pure MIT license. The goal is a truly self-hostable, zero-commercial-strings scheduling platform for individuals and small teams who don't need enterprise features but do need full data ownership. The technical stack is unchanged from Cal.com: Next.js, React, tRPC, Prisma ORM, and Tailwind CSS, with support for Google Calendar, Outlook, Daily.co video, email notifications, and standard event type booking flows. The project effectively resolves the "open core trap" by maintaining a clean split: if you want enterprise features, pay Cal.com. If you want a completely free, auditable, no-vendor-lock scheduling system, Cal.diy is the answer. With 41.5k stars (inherited from the Cal.com fork lineage), it has massive visibility. The maintainers are explicit that this is best suited for advanced self-hosters with server admin experience, not a one-click deploy for non-technical users. But for developers who want scheduling infrastructure without SaaS dependencies, it's arguably the cleanest option available.
AI Productivity
Sup AI
Runs 339 LLMs in parallel and downweights the hallucinating ones.
50%
Panel ship
—
Community
Free
Entry
Sup AI is an ensemble AI assistant that runs your query through 339 language models simultaneously, measures per-segment confidence across all responses, and synthesizes a final answer that amplifies agreement and suppresses likely hallucinations. The team claims a 52.15% score on Humanity's Last Exam (HLE) — 7.41 percentage points above the single best model — which, if verified, would make it the highest-scoring system on the benchmark to date. The underlying mechanism works like an LLM panel: each model votes on sub-claims within the response, confidence is estimated by agreement density, and the final output surfaces high-confidence segments while flagging uncertain ones. It's designed to reduce hallucination rate on factual tasks, not improve reasoning per se — the models in the ensemble aren't doing collaborative chain-of-thought, they're voting on outputs. Sup AI was built by Ken Mueller (Stanford, CEO) and Scott Mueller (AI Research Scientist) and launched on Product Hunt today. Pricing starts with $10 in free credits, no auto-charge, with a credit card required to start. The HLE benchmark claim is the headline and will face scrutiny — if verified, this is a meaningful research result. If it's cherry-picked, it's still a usable product with a differentiated architecture.
Reviewer scorecard
“The open core model has always been a tension with Cal.com — features gated behind enterprise licensing in a supposedly open-source project. Cal.diy resolves that cleanly. The stack is familiar, the MIT license is genuine, and for anyone building a product that needs scheduling infrastructure, this is the right starting point.”
“The HLE claim needs independent verification, but the underlying ensemble approach is architecturally sound for factual Q&A tasks. Running 339 models is expensive — pricing will be the gating factor for production use. The $10 free credit is a fair trial.”
“This is a maintenance burden in disguise. You're now responsible for keeping a large, complex Next.js codebase patched, secure, and up-to-date with upstream Cal.com changes — changes that may or may not land in the DIY fork on any predictable schedule. For most teams, Cal.com's free tier or Calendly is simply less operational overhead.”
“Extraordinary claims require extraordinary evidence. A 7.41 point jump on HLE via ensembling — without publishing methodology — smells like benchmark gaming. The latency of running 339 models in parallel is also a real concern for anything other than async research tasks.”
“Scheduling is increasingly the integration surface AI agents use to take real-world actions — booking meetings, blocking time, managing availability across workflows. Having a fully controllable, self-hosted scheduling layer that AI agents can write to without SaaS rate limits or webhook restrictions is a genuine infrastructure advantage for agentic systems.”
“Model ensembling is an underexplored direction in the race to reduce hallucination. If Sup AI's approach scales, it could be more durable than fine-tuning individual models — you get the wisdom of the crowd across model families, training data, and architectures simultaneously.”
“For content creators or solopreneurs who just need a Calendly replacement, self-hosting a full Next.js stack is overkill. The UX of the base Cal.com is fine but not exceptional, and the enterprise features you're losing (like organization-level insights) are actually useful for managing content calendar coordination across a team.”
“For creative work, ensemble outputs tend to regress toward the mean — you get the most-agreed-upon version of something, which is usually the least interesting version. This is a tool for factual accuracy, not creativity. I'd stick with a single strong model for writing.”
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