> For the complete documentation index, see [llms.txt](https://docs.ndax.in/v3/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ndax.in/v3/fix/sequence-diagram.md).

# Sequence Diagram

### Connectivity and Logon <a href="#connectivity-and-logon" id="connectivity-and-logon"></a>

The API client must establish a FIX session by sending a `Logon (35=A)` message. NDAX will act as an acceptor for all FIX sessions.

<figure><img src="/files/uMdCBLnwKRNmAWw5XPQn" alt=""><figcaption><p>National Digital Asset Exchange's FIX Logon Message Flow</p></figcaption></figure>