Our API plans mainly differ by the number of calls they include.
Other/meta calls are addressed to search engines (receiving metadata).
Download calls are actual downloads (receiving content).
Free requests - icons in PNG format ≤100x100 px; animated icons in GIF format.
Other/meta calls - any API requests that do not contain the content of an icon (the user receives icon metadata such as its name, styles, category, etc.).
Download calls - direct download of icons in sizes/formats other than free ones (the user receives content or metadata with content).
Let's say a user performs a search and views an icon. In this scenario, it would be a meta/other call if the icon is only previewed (<100x100 px) but not added to the project. However, it would be considered a download call if the user requests a high-quality URL and adds the icon to their project.
The standard ($250/mo) API plan includes up to 5K requests to search engines and up to 1000 monthly download calls. Every additional download adds $0.05 more to the monthly plan. All the other extra calls add $0.001.
You can find more information in the documentation on devportal: Icons8 API documentation.