Zoho CRM API limits are counted in credits, not calls. Each edition gets an allowance of credits per rolling 24 hours, made of a base amount plus credits for every user license, up to a ceiling. Apart from Bulk Read downloads there is no per-minute limit: Zoho caps how many calls may run at the same time instead.
The numbers above come from Zoho's API limits page, with the day we last checked them.
How to read the limits
Credits are weighted. A plain read costs one credit, writes are charged per group of records, and bulk jobs cost a large fixed amount whatever their size, so a small bulk job can cost more than the same work done with ordinary calls.
Concurrency is the real speed limit. Each edition allows a set number of calls in flight, and a lower sub-concurrency limit, the same on every edition, covers heavy calls such as converting a lead, the Query and Composite APIs, and inserts or updates of more than a few records.
How to plan a sync in credits
Count the reads and writes and price each one, then group writes so each call carries as many records as allowed. Use Bulk Write and Bulk Read only when the record count is large enough to beat their fixed cost.
Keep the calls in flight under your edition's concurrency limit, and under the sub-concurrency limit for heavy calls. A sync that runs many calls in parallel hits that cap long before it runs out of credits, so run fewer calls at once, not fewer calls.
What to do next
Look up the tool on the other end of your pipeline and plan around the tighter limit. Pipedrive also weights calls, against a daily token budget, while HubSpot counts each call the same.
In Oneprofile, Zoho CRM connects as a source or a destination, and each export can be held to a rate you set in requests per minute.