Client SDKs
Vexil provides client SDKs for reading feature flags from your application code. All SDKs follow the same pattern:
- Initialize a client with a provider (env, sidecar, or configmap)
- Call typed methods:
Bool(),String(),Int(),JSON() - Get the default value back if the flag is not found or disabled
Providers
| Provider | Source | Use When |
|---|---|---|
| env | FLAG_* environment variables | Flags delivered via envVar |
| sidecar | HTTP to localhost:8514 | Flags delivered via sidecar |
| configmap | Mounted files from a directory | Flags delivered via configMap |
Quick Comparison
// Go
client, _ := vexil.New(vexil.WithEnvProvider())
darkMode := client.Bool("dark-mode", false)
# Python
client = Client(provider="env")
dark_mode = client.bool("dark-mode", default=False)
// Node.js
const client = new Client({ provider: 'env' });
const darkMode = await client.bool('dark-mode', false);
// .NET
using var client = new VexilClient(new EnvProvider());
var darkMode = client.Bool("dark-mode", false);