## TL;DR

The client stored 'we are rate limited' as one global flag, so a 429 on one endpoint paused every endpoint for every API key. Track rate-limit state per endpoint (and per key), so a throttle on one route does not freeze the rest.

## Error

```text
one slow endpoint's 429s paused the entire sync, including unrelated endpoints
```

## Steps

1. Find the global rate-limit flag in the client Expected: you locate the shared state.
2. Replace it with per-endpoint (and per-key) backoff state Expected: throttles are scoped.
3. Re-run the sync and throttle one endpoint deliberately Expected: other endpoints keep moving.
4. Add a test asserting a 429 on route A does not delay route B Expected: it cannot regress.

## When to use

- One throttled endpoint freezes everything
- Rate-limit state is global

## When not to use

- The provider rate-limits the whole key globally (then global is correct)
- Each key has its own client instance already

## Tool compatibility

- Scoped rate-limit state
- Shared API clients

## Variant phrasings

### 429 froze all endpoints

Your rate-limit flag is global. Scope backoff per endpoint and per key.

### one throttle paused everything

Same: per-route backoff state.

## Why it happens

The simplest backoff implementation is a single sleep flag. It works in demos with one endpoint and one key, then falls over in production.

## Edge cases

- Respect Retry-After per endpoint; a global earliest-retry time has the same bug
- Circuit breakers are per-dependency for the same reason

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_kMICYQTQlTyI1xsjOydh7w