As the Synapse login mechanism needs an attribute to uniquely identify users, and Mastodon's endpoint does not return a `sub` property, an alternative `subject_claim` has to be set. Your Synapse configuration should include the following:
As the Synapse login mechanism needs an attribute to uniquely identify users, and Mastodon's endpoint does not return a `sub` property, an alternative `subject_template` has to be set. Your Synapse configuration should include the following:
```yaml
oidc_providers:
@@ -585,7 +585,9 @@ oidc_providers:
scopes: ["read"]
user_mapping_provider:
config:
subject_claim: "id"
subject_template: "{{ user.id }}"
localpart_template: "{{ user.username }}"
display_name_template: "{{ user.display_name }}"
```
Note that the fields `client_id` and `client_secret` are taken from the CURL response above.