---
title: "Level 4 overview | Grafana Labs"
description: "Introduction to custom instrumentation"
---

> For a curated documentation index, see [llms.txt](/llms.txt). For the complete documentation index, see [llms-full.txt](/llms-full.txt).

## Level 4: Custom instrumentation

**What you learned in Module 4:**

- Transaction insights let you debug specific requests.
- Distributed tracing shows the full request path across services.
- Continuous profiling reveals code-level performance hotspots.
- Frontend observability captures real user experiences.

* * *

**What you’ll do in this module:**

You’ll explore custom application observability:

- **Why Level 4** — When auto-instrumentation isn’t enough
- **What Level 4 provides** — Custom metrics, spans, and application context
- **Where to learn more** — Resources for custom instrumentation

**Estimated time:** 5 minutes