Check they use it
With a service this size, do not assume. A code for a platform somebody has never signed up to means they have to create an account, move nothing across, and maintain a second subscription alongside the one they already pay for.
If you know they care about audio quality — if they have mentioned lossless, or own decent headphones — this lands well. Otherwise pick something in the music category they already use.
Tiers and what changes
The service sells more than one tier, separated largely by audio quality. The price gap is meaningful, so a fixed amount covers a different number of months depending on which tier they are on.
If the gift is meant to be "three months", ask which tier. Otherwise present it as a contribution.
Billing route
Same question as the rest of the category: if they subscribed through a phone app store, that platform bills them and a service code may not apply. Have them check.
Availability
Smaller service, narrower footprint. It is not available in every country, and where it is, gift options vary. Tell us the country and we will confirm what exists rather than assuming.
Why it suits some people very well
For a listener with good equipment, higher-quality streaming is a real difference rather than a marketing line. This is one of the few gifts in this category that a recipient might genuinely not buy for themselves and be pleased to be given.
Asking for one
Country, tier if you know it, and whether they already have an account.