+## Generation of API code
+
+The CAPIF APIs are generated from the OpenAPI specifications provided by 3GPP. The `generate.sh` script downloads the
+specifications from 3GPP, fixes them and then generates the APIs. It also generates the mocks needed for unit testing.
+The specifications are downloaded from the following site; https://www.3gpp.org/ftp/Specs/archive/29_series. To see
+the APIs in swagger format, see the following link; https://github.com/jdegre/5GC_APIs/tree/Rel-16#common-api-framework-capif.
+**NOTE!** The documentation in this link is for release 16 of CAPIF, the downloaded specifications are for release 17.
+
+To fix the specifications there are three tools:
+- `commoncollector`, collects type definitions from peripheral specifications to keep down the number of dependencies to
+ other specifications. The types to collect are listed in the `definitions.txt`file. Some fixes are hard coded.
+- `enumfixer`, fixes enumeration definitions so they can be properly generated.
+- `specificationfixer`, fixes flaws in the specifications so they can be properly generated. All fixes are hard coded.
+
+### Steps to add a new dependency to the commoncollector
+
+When a dependency to a new specification is introduced in any of the CAPIF specifications, see example below, the following steps should be performed:
+
+For the CAPIF specification "TS29222_CAPIF_Discover_Service_API" a new dependency like the following has been introduced.
+websockNotifConfig:
+ $ref: '**TS29122_CommonData.yaml#/components/schemas/WebsockNotifConfig**'
+
+1. Copy the bold part of the reference and add it to the `definitions.txt` file. This step is not needed if the type is already defined in the file.
+2. Look in the `generate.sh` script, between the "<replacements_start>" and "<new_replacement>" tags, to see if "TS29122_CommonData"
+ has already been replaced in "TS29222_CAPIF_Discover_Service_API".
+3. If it has not been replaced, add a replacement above the "<new_replacement>" tag by copying and adapting the two rows above the tag.
+
+## Build and test
+
+To generate mocks manually, run the following command:
+
+ go generate ./...