"Supports custom code" means nothing. Here's the 3-level ruler that tells you if a low-code platform will lock you in.

Every low-code vendor says "we support customization." But supports is a weasel word — recoloring a button is customization, and rewriting a scheduling engine is also customization. What actually decides whether a platform locks you in is how far up its extensibility goes. Here's a ruler. The three levels of customization Level What you can do Most no-code A real dev framework L1 — Config Fields, forms, workflows, permissions, themes ✅ ✅ L2 — Extension Custom components, custom actions, external API calls, business rules ⚠️ limited ✅ L3 — Framework Modify/extend the core, custom engines, deep rewrites, source under control ❌ wall ✅ (when open/controllable) Where it stops is where your ceiling is. Plenty of no-code platforms are delightful at L1, then hit "can't do that" at L2/L3 — and you retreat to writing your own thing next to it. Now low-code is the burden. Why you get locked in Black-box SaaS — no source, so any extension point the vendor didn't expose is simply out of reach. Two sources of truth — your extension code and the platform's config live in different systems, so a platform upgrade breaks/voids your work. Crippled self-hosting — the on-prem edition quietly drops extension capabilities. Closed ecosystem — only their component marketplace; your stack can't get in. How model-driven + open source raises the ceiling One unified extension system — your extensions (custom fields/components/actions) and the platform itself are built on the same metadata. Extension isn't a bolt-on, it's a first-class citizen — upgrades don't wipe your customizations. Source under your control — open + self-hostable is what makes L3 framework-level extension actually possible: an extension point you can't reach, you can add. AI at the metadata layer — AI-generated extensions land in the same model, so they stay maintainable and evolvable. That's the road Oinone takes: 100% metadata-driven, front + back end open source, self-hostable — customization reaches L3. How to stress-tes