REST API guide

Querying data, errors, limits, and what applies to every call.

• Query data The whole query body of the Developer API, from dimensions, measures and filters to paging, counts, totals and time zones, and how to read the answer.
• Errors The problem format the Developer API answers with, and every code it can return, with its status and what to do about it.
• Rate limits The Developer API's limits per key, person and address, requests running at once, the daily row budget, values by plan, Retry-After, reading your limits from whoami, and a backoff snippet.
• The security model What applies to every Developer API call, from the person reloaded as they are now to access levels, row policies, hidden fields, source errors and what Halo records.
• Webhooks Halo posts to your address when something happens. Every event and its payload, how to check the signature, how retries work and how to drop repeats.
• Read websites and the directory Read your Halo CMS websites and your Halo CRM listings and businesses with an API key. What's in them, how to page, and what's left out on purpose.