Both terms refer have the same meaning. If there are any doubts on how to obtain it, please refer to the following guide.
Generally speaking, access token represents authorization from one Aliexpress seller account. In other words, the relationship between access token and Aliexpress seller account is 1 to 1.
For appKey under a Commercial developer, it could help to authorize mutiple Aliexpress seller accounts, therefore generating mutiple access tokens. However, for appkey under a self developer, it could authorize one Aliexpress seller account, which is the seller account belonged to the Self developer himself.
The validity time depends on the type of account:
Self-Developer: For those who registered as a self-developer, the token lasts for a whole year.
If the token is going to expire soon. It is recommended to renew it or at least notify of its expiracy date 2-3 days before the expiracy date. It is imperative t do so because with an expired token none of the API requests will be processed.
