More newsletter settings in the API

The /v1/newsletters endpoint has always let you manage the basics — name, description, CSS, branding colors — but a lot of the settings you could configure in the UI weren't available programmatically. That changes today: we've added a big batch of new fields to the Newsletters API.

What's new

Locale, templates, and theming:

• locale — set your newsletter's language (French, German, Spanish, and eleven others)
• template — choose your email template (classic, modern, plaintext, naked)
• archive_theme — pick your archive page theme (classic, modern, arbus, lovelace, myrna)
• timezone — set the timezone for scheduling and date display

Custom transactional emails: You can now fully customize the subject, body, and template for all of your transactional emails via the API: subscription confirmation, subscription confirmed, confirmation reminder, premium confirmation, expired trial notification, gift subscription, and gift unsubscription.

Social and sharing:

• socials — manage your linked social media accounts
• sharing_networks — control which share buttons appear on your archives

Archive and branding:

• announcement_bar_text, announcement_bar_background_color, announcement_bar_visibility — configure your archive's announcement bar
• reply_to_address — set a custom reply-to email
• subscription_redirect_url and subscription_confirmation_redirect_url — redirect subscribers after signup or confirmation

All of these fields work with both POST (create) and PATCH (update) requests. This is especially useful if you're using Buttondown as a headless newsletter provider and want to manage everything programmatically.