# Developer Guide

## Document Information

### Copyright Notice

![](https://1577345028-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-MiVMn-5GzUw-bGYHPT8%2Fuploads%2Fgit-blob-dcc15fd6a92e21ac527032fce03e725afcc37a84%2FShareAlike.png?alt=media)

This document is released under the [Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license](https://creativecommons.org/licenses/by-sa/4.0/).

### Status

This document is in draft.

### Author / contact

[Joris Scharp](mailto:joris@headease.nl)\
[Headease B.V.](https://www.headease.nl/)

## Important differences with Koppeltaal 1.3.x

| Concept                | **KT 1.3.x**                                | KT 2.0                   |
| ---------------------- | ------------------------------------------- | ------------------------ |
| **FHIR Exchange**      | Messaging                                   | RESTful API              |
| **Content Validation** | Separate service                            | Built-in                 |
| **Authorisation**      | None - application has access to everything | On resource & CRUD-level |

### FHIR Exchange

By using the (FHIR) RESTful API exchange there is a single source of truth. Koppeltaal 1.x acted as a message broker, giving each participant the responsibility to keep all data up-to-date.

Another big advantage is that Koppeltaal 2.0 works with small messages. So no self-contained bundles. This saves a lot of data being transferred over the line and the chance of 409 Conflicts are considerably reduced.

### Content Validation

Previously, a separate service could be used to check whether the content of a `Bundle` is valid. However, this validation was not enforced by the Koppeltaal server.

Koppeltaal 2.0 uses [profiles](https://simplifier.net/Koppeltaalv2.0/~resources?fhirVersion=R4). A profile indicates exactly what the rules are per [Resource](https://www.hl7.org/fhir/r4/resourcelist.html). The Koppeltaal server can enforce profiles by validating that the Resources adhere to the profile.

### **Authorisation**

Applications connect to the Koppeltaal server. Within "Domeinbeheer" (Domain Management), roles are assigned to the applications. A role can contain multiple CRUD permissions per Resource. With Koppeltaal 2.0, you are only allowed to work with resources to which you are entitled. With Koppeltaal 1.x, applications can see everything that they are subscribed to within a Domain.

{% hint style="warning" %}
Note: Resources are managed at application level Koppeltaal 2.0.

The golden rule is that the application **itself** determines which resources are accessible at user level within the application.
{% endhint %}

##


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://devguide.koppeltaal.nl/readme.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.