Klor and ConfigCat

Both are deliberately small. Both have a flat, readable pricing model rather than a call with sales. Both ship SDKs that cache and evaluate rather than asking you to think about transport. Both treat a flag as a typed value with targeting rules, which is the right primitive.

ConfigCat has more SDKs, more years, and a percentage rollout model that works. If you are on it and content, there is no crisis here.

• Update gating is built in. Minimum supported version, latest version, and a blocked build list are fields rather than flags you write comparison logic around. This is the difference that matters if you ship a mobile app.
• Publishing is explicit and immutable. Editing stages a change; publishing compiles a snapshot you can roll back to. ConfigCat saves changes live, which is faster and gives you nothing to restore.
• Sensitive flags never reach a public payload. The confidentiality boundary is enforced when the snapshot is compiled, not by remembering which SDK key you used.
• A management API and typed values checked server side against the flag type, so a number flag cannot be published carrying a string.

• SDK coverage. Ten or so languages against Klor’s one. If your stack is not JavaScript, this decides it.
• Track record and a support team.
• Percentage rollouts and targeting have been in production for years, against Klor’s months.
• Per seat pricing that is already defined. Klor is free while it is young, which is a different kind of uncertainty.

If you ship a React or React Native app, want force update without writing it, and want to be able to undo a config change without remembering what it was, Klor is the closer fit. If your stack is polyglot or you need a vendor with years behind it, ConfigCat is the safer one, and saying otherwise would not survive your first week of using both.