Salesforce Flow vs. Apex: When to Use Which

One of the most common questions among Salesforce admins and developers: when should you use a Flow, and when should you write Apex code? Both tools automate business processes, but they have very different strengths and limitations.

Salesforce Flow: Full Power, No Code

Salesforce Flow (formerly Lightning Flow) is Salesforce's visual automation tool. It lets you build complex business processes without writing a single line of code — directly from the Setup interface.

• Best for: automating field updates, notifications, approvals, and record creation
• Key advantage: maintainable by an admin — no code deployment required
• Limitation: can slow down on very large volumes (>50,000 records)
• Types available: Record-Triggered Flow, Screen Flow, Scheduled Flow, Autolaunched Flow

Apex: Maximum Flexibility Through Code

Apex is Salesforce's proprietary programming language, similar to Java. It lets you implement any business logic and interact with external APIs — with full control over execution.

• Best for: bulk processing (Batch Apex), complex API integrations, advanced conditional logic
• Key advantage: superior performance on large volumes, full execution control
• Limitation: requires a developer and deployment via changeset or CI/CD pipeline
• Typical use cases: cascading update triggers, third-party API callouts, complex schedulers

Salesforce's Official Decision Framework

Salesforce officially recommends defaulting to Flows whenever possible. Apex should be a last resort — only when Flow hits its technical limits.

• Trigger on record change → Record-Triggered Flow
• Guided user interface → Screen Flow
• Scheduled bulk processing → Batch Apex if >10,000 rows, otherwise Scheduled Flow
• External API call with complex conditional logic → Apex
• Reusable logic called from multiple Flows → Invocable Apex

Combining Flow and Apex: The Best of Both Worlds

You can — and often should — use both together. A Flow can call an Apex method via an Invocable Action, keeping the visual business logic in Flow while delegating complex processing to Apex. This gives admins visibility without sacrificing developer-grade performance.

Real-World Example

A B2B software company automates its contract renewal process: a Record-Triggered Flow fires 60 days before expiration, creates a follow-up task for the rep, and sends a personalized email. When the deal value exceeds $50,000, the Flow calls an Invocable Apex method that queries an external pricing API to generate a custom quote in CPQ. The admin maintains the Flow visually while the developer owns only the Apex integration logic.

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