Custom functions in Zoho CRM are serverless scripts written in Deluge (Data Enriched Language for the Universal Grid Environment), Zoho's proprietary scripting language (Zoho CRM help: Custom Functions).
Key capabilities:
- Read and write to any CRM module via built-in Deluge tasks (zoho.crm.getRecords, updateRecord, etc.).
- Communicate with third-party REST APIs via
get urlandpost urltasks. - Send emails, manipulate lists and maps, parse XML, call other functions.
- Can be triggered by: Workflow rules, Approval processes, Blueprints (After Transition), Schedules, Custom buttons, and the new Kiosk Studio.
- Up to 6 custom functions per workflow rule (1 instant + 5 time-based).
- Transfer up to 10 CRM field values to third-party applications per function invocation.
Deluge Script Builder (low-code): A drag-and-drop code assistant that converts business logic into Deluge code without requiring manual syntax writing (Zoho CRM help: Custom Functions Programming).
Function Trails: A dedicated section for drafting, testing, and revising functions before associating with live automations—keeping experimental code separate from production rules.
Zia Formula Expression Generator (Q1 2026): Describe a formula in plain language; Zia generates the complete Deluge formula expression with correct syntax, which can then be inserted into a formula field (Zoho CRM Q1 2026 update).
April 2026—CRM Integration Tasks on Deluge V8 APIs: New Deluge integration tasks for Zoho CRM built on V8 APIs, supporting Create Record, Bulk Create, Get Records, Get Related Records, Fetch by ID, Update, Bulk Update, Update Related Record, Search, Attach File, Convert Lead, Get Fields, and Upsert (Releasebot: Zoho April 2026 updates).