Changelog

Changes an integration would notice, newest first. Additions within v1 never break existing code; see versioning.

2026-09-14

• Published these developer docs.
• A 429 from the rate limit now uses the standard error shape, with the type rate_limited, instead of a bare message.

2026-09-11

• Connect several applications to one account, each with its own key, abilities and optional sending-domain limits.
• Replace a key with an overlap of up to a week, so the old one keeps working while you deploy the new one.
• New newsletter:read ability, for a key that can look subscribers up but not change them.

2026-09-10

• Webhooks: signed notifications for email delivery events, newsletter subscribers, preference changes and received mail.
• Every response carries X-Reggio-Request-Id, and every error repeats it as error.request_id.
• PATCH /api/v1/emails/{id} moves a scheduled message to a new time.

2026-09-09

• The newsletter subscriber API: lists, fields, add or update, look up and unsubscribe, with the newsletter:manage ability.

2026-09-08

• Send a published email template with template_id and variables.
• Validation failures use the standard error shape, with error.fields.
• suppressed is returned on every kind of send, including scheduled sends and each message in a batch.

2026-09-01

• Scheduled sends with scheduled_at, cancelled with DELETE /api/v1/emails/{id}.
• POST /api/v1/emails/batch for up to 100 messages at once.
• tags, custom headers and the Idempotency-Key header.
• Attachments, by content or by link, and inline images.
• GET /api/v1/emails/{id} to see what happened to a message.

2026-08-24

• The transactional email API: POST /api/v1/emails.
• SMTP credentials for any verified sending domain.