> For the complete documentation index, see [llms.txt](https://docs.bimcat.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bimcat.org/user-manual/usage/sign-in.md).

# Sign In

The **Sign In** button allows a user to sign in to the EC3 Building Transparency service, which is essential for using most of the BIM Climate Action Tool functions.

<figure><img src="/files/JCJ9lC6dHAJGzs5sL2lc" alt=""><figcaption></figcaption></figure>

This button has the same functionality as the [corresponding item](/user-manual/usage/tallycat-beta/sign-in.md) under the **Web Analysis** drop-down menu.