Architecture
Flags are defined and configured in the dashboard, distributed via a CDN-backed snapshot API, and evaluated entirely within the SDK. There is no per-evaluation network call. The SDK fetches a snapshot of all flag configurations on startup, caches it locally, and runs the evaluation engine in-process on every call.- Zero evaluation latency — flag checks are pure in-memory operations.
- No single point of failure — stale cached snapshots serve traffic even when the origin is unreachable.
- Deterministic rollouts — the same user always lands in the same bucket, across all platforms and restarts.
Flag types
| Type | Return type | Typical use case |
|---|---|---|
boolean | bool | Feature gates, kill switches, A/B experiments |
string | string | UI variants, copy testing, configuration by name |
number | number | Numeric thresholds, price multipliers, capacity limits |
object | Record / object | Structured configuration payloads |
SDK platforms
React
Hooks for React 18+ web applications
React Native
Hooks with AsyncStorage persistence and foreground refresh
.NET
Hosted service integration for ASP.NET Core 8+
Key concepts
- Projects, Environments & Applications — the resource hierarchy and how SDK keys map to environments
- Flags — how flags are structured, typed, and namespaced
- Targeting — rule-based evaluation using evaluation context attributes
- Evaluation — the complete evaluation algorithm and reason codes