Supastarter is a polished Next.js + Supabase boilerplate for JavaScript teams; CleenUI is a licensed .NET + React codebase with a real ASP.NET Core backend, 524 pre-built endpoints, SignalR real-time messaging, and a 12-project async services layer.
Supastarter is the most mature JavaScript SaaS starter in the market — a Turborepo monorepo with a Next.js app, Supabase backend, Drizzle ORM, Stripe payments, and shadcn/ui components. It's a genuinely solid foundation for a JavaScript-first team. CleenUI targets a different engineering problem at a different scale: a licensed ASP.NET Core 8 + React 18 codebase with 524 real API endpoints, 300+ database tables, 700+ stored procedures, SignalR real-time messaging, Azure Functions + WebJobs background processing, and 20 vertical-slice modules covering auth, accounts, support, observability, translations, notifications, messaging, tasks, AI operations, assessments, and more. The comparison is less 'which starter is better' and more 'what runtime fits your team and how much of the application should already exist on day one.'
| Category | CleenUI | Supastarter |
|---|---|---|
| Runtime | .NET 8 + React 18 (separate API + SPA) | Node.js / Next.js (full-stack React) |
| Backend | ASP.NET Core 8 Web API — 524 documented endpoints across 25 functional groupings | Next.js API routes + Supabase (PostgreSQL) |
| Database | Azure SQL — 300+ tables, 700+ stored procedures, Dapper + ADO.NET (no ORM) | Supabase (PostgreSQL) via Drizzle ORM + auto-migrations |
| Background processing | 12-project .NET solution: 3 Azure Functions (translation, media safety, video encoding) + 2 WebJobs + 6 shared libraries | None included — queue infrastructure is your problem |
| Real-time | SignalR hub: conversations, participants, presence, reactions, read receipts, draft state, media | None included — Supabase Realtime can be wired separately, not pre-built |
| Frontend components | 60+ accessible React components in 12 categories | shadcn/ui on Radix primitives |
| Auth | Auth0 + JWT + RBAC + ABAC + row-level isolation + API-key auth (M01) | Auth.js / Supabase Auth + organization management |
| Payments | Stripe + M14 Vendor Marketplace (subscriptions + webhook + marketplace layer) | Stripe Subscriptions + webhook handler |
| i18n | M05 Translation & Languages — full API + DB layer, runtime translation, browser-code resolution, cache warmer | next-intl (string translation files) |
| Notifications | M06 Notify Templates (engine with versioning, history, preview-send, phrase translation) + SignalR in-app notifications | Email via Resend (transactional templates) |
| Monorepo / solution | Single Visual Studio solution (.NET projects) + single Vite SPA | Turborepo monorepo (web, saas, docs, mail-preview, shared packages) |
| Distribution | Custom-scoped engagement (one-time license, architect-led) | One-time purchase (~$499 commercial license) |
These capabilities are pre-built in CleenUI. Supastarter has no equivalent — you'd build them from scratch or wire a third-party integration.
SignalR hub — conversations, participants, presence indicators, reactions, read receipts, draft state, and media attachments. Pre-built end to end from database tables through API through hub events through React components. Supastarter ships no real-time layer.
A 12-project .NET solution: 3 Azure Functions (translation, media safety, video encoding) + 2 WebJobs (scheduled translation sweeps, continuous thumbnail generation) + 6 shared C# class libraries. Supastarter ships no async infrastructure — you choose and wire a third-party job queue.
M03 — help articles, categories, public content endpoints, search, and content association. Builds the customer-facing support surface that every B2B product eventually needs.
M09 — model config and platform routing across 6 AI vendors, prompt CRUD with versioning and history restore, dynamic prompt execution, and agent management. Deeper than dropping in an AI SDK.
M13 — full survey engine: question builder, wizard player, section/step CRUD, personality instruments (Big-Five / DISC / MBTI-style), and org-fit panels. Supastarter has no equivalent.
M11 — version-controlled agreements with user-acceptance recording and public policy lookup. Standard requirement for any regulated-industry or enterprise SaaS deal.
Pick Supastarter when your team is JavaScript-first and a Next.js + Supabase stack is non-negotiable — it's a well-built foundation for that ecosystem. Also reach for it when a smaller scope or limited budget makes a licensed .NET engagement impractical.
Pick CleenUI when your backend needs to be a real .NET API (not server actions), when real-time messaging is a product requirement (Supastarter ships none), when background processing is part of the application (Supastarter ships none), or when you want to own production-grade SQL with 700+ stored procedures rather than manage ORM migrations against Supabase.