> ## Documentation Index
> Fetch the complete documentation index at: https://bytekit.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Observability

> Overview of ByteKit observability modules — structured logging and performance profiling.

## What this group covers

Use these modules when you need visibility into runtime behavior without dragging observability concerns into every feature module.

<CardGroup cols={2}>
  <Card title="Logger" icon="list" href="/api-reference/logger">
    Structured logging for browser and Node.js with namespaces, levels, transports, and child loggers.
  </Card>

  <Card title="Profiler" icon="stopwatch" href="/api-reference/profiler">
    Execution timing, checkpoints, and performance measurement for async and sync work.
  </Card>
</CardGroup>

## Quick example

```ts theme={null}
import { createLogger } from "bytekit";
import { Profiler } from "bytekit/profiler";

const logger = createLogger({ namespace: "checkout", level: "debug" });

const profiler = new Profiler("checkout");
profiler.start("create-payment");

await createPayment();

profiler.end("create-payment");
logger.info("Payment created", profiler.summary());
```

<Tip>
  Combine `Logger` and `Profiler` to emit structured timing data alongside your application logs.
</Tip>