Your first link

Follow Quick start to create a standard redirect.

behavior is explicit: use STANDARD for a simple redirect. Supply a valid originalUrl; optional UTM fields include utmSource, utmMedium, utmCampaign, utmTerm and utmContent.

Generated short codes have seven alphanumeric characters. Custom aliases have separate validation rules; they are not restricted to the generated format. An unavailable alias is rejected. Use the API response as the source for the final short URL.

Do not send tags or title as invented creation fields. Social preview fields are ogTitle, ogDescription and ogImageUrl. Tags are managed through their own API operations.

Review Links before adding expiry, routing or a password.