Deezer User Token [verified]
Some community sources suggest that if you request the offline_access permission during OAuth, you may receive a token with an expires=0 value, which some interpret as “never expires”. However, this behaviour is not guaranteed across all versions of Deezer's API, and relying on a token never to expire is risky.
If you are building a public application, you should use the official method: deezer user token