# Developer documentation/API

This part of the documentation is for you if you want to improve python-fints, but also if you just want to look behind the curtain.

Contents:

- Parsing and serialization
  - `FinTS3Parser`
  - `FinTS3Serializer`
- FinTS Segments
  - `FinTS3Segment`
  - All Segments
- FinTS Segment Sequence
  - `SegmentSequence`
- Working with Segments
- Defining new Segment classes
  - Base types
  - Field types
  - Constructed and helper types