# Timeout
source: https://docs.chalk.ai/docs/timeout

## Maximum execution time for resolvers

Computing features associated with third-party services can be unpredictably slow.
Chalk helps you manage such uncertainty by specifying a resolver timeout duration.

Chalk will instantaneously (±1ms) cease waiting for a resolver whose
runtime has exceeded the specified timeout duration. Simultaneously,
via parallel execution, Chalk will return other crucial features whose
resolvers did not time out.

To specify a timeout, use the timeout keyword argument to either
@online or @offline:

### Example

```
from chalk.features import online, offline

@online(timeout="200ms")
def resolve_australian_credit_score(
    driver_id: User.driver_id_aus,
) -> User.credit_score_aus:
    return experian_client.get_score(driver_id)

@offline(timeout=timedelta(milliseconds=50))
def resolve_canadian_credit_score(
    user_si_number: User.social_insurance_number,
) -> User.credit_score_can:
    return equifax_client.get_score(user_si_number)
```

See Duration for supported durations.

### Behavior upon timeout

### Direct timeout

If a query's output feature is directly resolved by a resolver that
timed out, Chalk will return an error with the error code RESOLVER_TIMED_OUT,
and its message will contain the name of the timed-out resolver.

### Upstream timeout

If a query's output feature is resolved by a resolver whose upstream
resolver has timed out, Chalk will return an error with the error
code UPSTREAM_FAILED.

The resolver that directly outputs the requested feature will not be
run (unless it marks its inputs as optional).

### Multiple output features

If your query contains multiple output features, Chalk will still
return the other features whose resolver did not time out.