A Client Has at Most One Reminder Configuration
client_id is unique across a reminder configuration. Creating a reminder for a client that already has one replaces it — send_to, copy_to_self and the entire rules array are overwritten. There is no error on a repeated POST; it’s the normal way to update a configuration in one call. See Configure payment reminders for a client.
Updating Replaces the Entire Schedule
PUT works the same way as create: send the complete rules array, not just the rule you want to change. Any rule omitted from the payload is removed, and rule ids are never returned, so there is no way to reference an existing rule to patch it individually. Read the current configuration with GET first if you only mean to change part of the schedule.
The Three Operators
Each rule is anchored on the invoice due date and fires relative to it:
A configuration can have between 1 and 5 rules, in any combination of operators.
Default Email Copy
There is no endpoint to fetch email templates. If a rule omitsemail_body, Qonto sends this default copy based on the rule’s operator:
email_title always has to be set explicitly — only email_body falls back to this default copy.
These defaults are localized in the recipient’s language; the table above shows the English copy.
Removing the Invoice Automation Add-on Deletes Every Reminder
If an organization’s Invoice Automation add-on is removed, every client’s reminder configuration in that organization is deleted immediately, and this cannot be undone — the configurations have to be recreated one by one. This applies regardless of whether the reminders were created via this API or the Qonto app. Build for this if you cache reminder state on your side: a404/403 on a reminder you previously created is expected after an add-on change, not a bug.