initFireweave (or the language equivalent), sitting on one runtime and one adapter. You evaluate control points and register targets. That is the whole v1 surface.
The runtime never invents an identity (you pass targetingKey) and evaluation never throws — failures come back as a Decision carrying your default.
The wire still says flagKey. The product noun is control point.
There is no OpenFeature provider in this picture. See OpenFeature.
1. Init with a required mode
mode is 'remote' or 'local' and is never inferred. Remote without credentials is a boot error.
Construct
InMemoryAdapter yourself for fixture-driven tests. See Adapters.
The SDK reads no environment variables. Your application may read FW_API_URL / FW_PROJECT_API_KEY and pass them in.
2. Initialize, then wait for a usable state
initFireweave / Init / Fireweave.init validates options, constructs the adapter, and brings the runtime to READY — or throws Configuration.
Reads before READY degrade to your default with NotReady.
The browser-shaped runtimes (Web, Swift) add a load-bearing STALE state: if the initial prefetch loses a 5 second ceiling, sync reads return defaults with reason STALE. That is not the same as READY with every control point off. See Lifecycle.
3. Register a target
A target is who the decision is for, keyed bytargetingKey.
Register durable properties once (login / device provision). registerTarget exists in all seven languages and never throws — check ok.
- Server SDKs:
registerTarget/register_target/RegisterTarget - Web and Swift:
registerTarget, plusidentify(register, then re-prefetch under that id)
kind (user | device) and properties. fw_-prefixed property keys are reserved and stripped server-side.
Two identity paths compose on fw-server: stored registerTarget properties, plus per-evaluate attributes (attributes win for that call). Local mode records in-process and traces [fireweave:local]. In-memory adapters and the repo test-server stub do not persist registration.
4. Evaluate a control point
The nine methods live oncontrolPoints / control_points / ControlPoints:
The argument is still
flagKey. Every evaluation produces a Decision: flagKey, value (or your default), optional variant, reason, and error fields. If the value looks like your default, inspect reason / the error kind.
A v1 read is side-effect free. No read emits telemetry as a consequence of being called.
5. Shut down once
Share one client. Shut it down once at process exit. Default bound is 10_000 ms where the language exposes it.- Node / Web / Python / Rust / Swift:
shutdown() - Java:
close() - Go:
client.Runtime().Shutdown(ctx)
What this flow is not
The SDK evaluates and registers targets. It does not wrap application code, advance a percentage ramp, or run client-side guardrails. Thereleases, exposures, signals, capabilities, and guardrails client namespaces are gone. Console wrap / ramp / Log-Alert-Block language is not part of this path.
Next: Architecture for layers and wire paths, or Quickstart to run an offline evaluate.