Local evaluation

Overview

A flag check is a function call: look at the in-memory snapshot, hash if needed, return a value. The SDK talks to the edge only to refresh that snapshot.

Hot path

shipd.isEnabled("new-checkout", { userId: "usr_8f2k19" });
// snapshot.flags["new-checkout"] + context → boolean

No HTTP, no WebSocket, no Postgres. If you need rules that query “everyone we saw last week,” that is not eval — it is a future control-plane feature. Eval stays local.

Refresh path

ready() / poll / snapshot.updated
        │
        ▼
GET /sdk/v1/snapshot   (ETag / If-None-Match)
        │
        ├── 200 → atomic replace
        ├── 304 → keep
        └── error → onError, keep last good

streamEndpoint only invalidates. The snapshot still comes from HTTP.

When the edge is gone

You configured	You get
`defaults`	those values
previous successful fetch	last good snapshot
browser `persist: true`	last good snapshot from localStorage, then refresh

Evaluation APIs do not throw. Unknown keys return the default and emit unregistered_flag.

Bucketing

Percentage conditions hash flagKey + userId (or attribute) into 0–10000. Same inputs → same bucket. Nothing is stored to make it sticky.

⌘I

Getting started

Guides

How-to

Concepts

Reference

Local evaluation

Overview

Hot path

Refresh path

When the edge is gone

Bucketing

Next

​Overview

​Hot path

​Refresh path

​When the edge is gone

​Bucketing

​Next

Overview

Hot path

Refresh path

When the edge is gone

Bucketing

Next