Mellow API
Bookings, availability and prices for one or more rentals, over one REST API.
Every call carries Authorization: Bearer sk_live_…. A key acts as one sales channel and reaches every rental that channel sells; bookings it makes land on that channel. Keys are made under Settings, API keys.
Dates and times are the rental's local time, written YYYY-MM-DDTHH:MM. Money is whole minor units with an ISO currency code: ISK has no decimals, so 25000 is 25,000 kr. Every price includes tax where the rental shows prices with tax.
Additive changes stay in v1: a new optional field, a new endpoint, a new enum value. Clients must tolerate unknown fields. Mellow aims to put a breaking change in a new major version beside this one. One break went into v1: on 2026-10-14 the dropoff fields became return fields, such as dropoffAt to returnAt, and the old names went.
/availability and /quotes, which ask about many at once.Idempotency-Key on every create: a retry with the same key and body returns the same booking, and a different body with the same key is refused. When the rental pauses a reseller's channel, its key still reads bookings. It gets no availability, offers or quotes, and a hold, a make, a change or a cancel answers 403 with paused.preview=true, which answers the change and writes nothing. Every write goes into the rental's price history with the key's name.