While both of the Altmetric APIs display Altmetric attention data and research output metadata, the Altmetric Explorer API and the Altmetric Details Page API are optimized for different functions. 

The Explorer API is optimized for exporting the data that you can see within the Altmetric Explorer. For example, the Altmetric Explorer can be used to search for all policy mentions associated with a particular search across output titles or a journal. Then, you can export this data using the Altmetric Explorer API. From then on, you will have programmatic access to the return data, which is always up-to-date.

The Details Page API is optimized for retrieving metadata, mention counts by source, and mentions, for individual research outputs. For example, you can query the Details Page API with a DOI for a research output, and the API will return all the relevant metadata and Altmetric attention data for the research output. 

The Explorer API and Details Page API are separate APIs. As they are structured independently of each other, the two APIs do not share the same field names. 

For example: 

The field for journal id in the Explorer API is: journal_id 

Whereas the field for journal in the Details Page API is: altmetric_jid

What data does each API provide?