# Debugging Code

[Requires Debug Add-on](https://www.blackfire.io/pricing)

Blackfire is built for code performance optimization. Hooking deep into the language engine, it enables developers to know exactly which code is executed, when, and how much resources it consumes. This opens doors to more than performance optimization: **debugging code**.

By default, Blackfire [prunes](../reference-guide/glossary) the least significant calls in the profiled code, and anonymizes SQL queries and HTTP calls (arguments, usernames, passwords, ...) before data is sent to our servers (see our [privacy and confidentiality documentation](../reference-guide/faq#blackfire-data-privacy)).

But the data we remove for profiling and privacy are potentially highly valuable during a debug session. The **Debug add-on** lets developers disable pruning and anonymization for specific requests.

To disable pruning and anonymization, check the *Enable debugging mode* box in the browser extension, or use the `--debug` option if creating profiles with `blackfire curl` or `blackfire run`.

![](../images/debug-addon.png)

Profiles generated with deactivated pruning and anonymization show:

- All function/method calls executed in the profiled code;
- SQL arguments in the SQL queries list, instead of question marks.

> **Note**
>
> As per [our terms of use](https://blackfire.io/terms-of-service) please ensure that you never send any personal or sensitive information to Blackfire while profiling non anonymized requests.

Additional notes:

- There is a known limitation for prepared SQL statements; arguments are never collected and only columns names are;
- This feature does not affect/add more data on the [timeline](understanding-timelines); it only does on [call-graphs](understanding-call-graphs);