Validation Rules vs Flow vs Apex Triggers

by Ratko Brzilov

This is one of the most common decision points for new admins and junior developers. All three tools run when a record is created or updated and at first they seem interchangeable. Because of that, many people choose based on familiarity and they use Flow because they learned Flow recently or they use Apex because they come from a programming background. But in Salesforce architecture, this choice actually matters a lot.

But in Salesforce architecture, this choice actually matters a lot.

Using the wrong tool doesn’t just make a solution slightly messy. Over time it causes slow save times, conflicting automation, and systems that are very hard to debug. I’ve seen orgs where opening a record takes several seconds simply because the same requirement was implemented in the wrong place.

The good news is that the decision is much simpler than it looks once you understand the real purpose behind each tool.

Validation Rules — The Data Gatekeeper

Validation Rules exist for one reason only: to stop bad data from entering Salesforce.

When a user clicks Save, Salesforce checks the conditions inside the rule. If the conditions are not met, the record does not save and the user sees an error message. That’s it. No automation runs, nothing updates in the background, and no records are created.

Validation Rules do not automate business processes. They protect the database.

Common examples:

These rules might feel small, but they are extremely important. Reports, dashboards, forecasting and automation all depend on accurate data. If incorrect data gets saved, every process built on top of it starts giving unreliable results.

Record-Triggered Flow — The Business Process Engine

Flow is where Salesforce actually starts doing work.

Unlike Validation Rules, Flow does not block the user. Instead, it reacts after a record is saved and performs actions automatically. This is Salesforce handling business processes without human involvement.

A Flow can:

Imagine a sales team marks an Opportunity as Closed Won. The company now needs a project created, an onboarding email sent and a customer success manager assigned. None of that is data validation: it is business workflow.

This is exactly what Flow is designed for. In fact, modern Salesforce best practice is a Flow-first approach. Workflow Rules and Process Builder were gradually replaced because Flow can handle almost all day-to-day automation while still being maintainable by admins.

Apex Triggers — The Heavy-Duty Option

Apex Triggers are custom code. They run before or after records are saved, just like Flow, but they give developers full control over the system’s behavior. Because of that, they are also the most powerful and the most expensive to maintain.

Triggers are not meant to be the default solution anymore. Salesforce now clearly recommends using Apex only when Flow cannot reasonably handle the requirement.

Situations where Apex makes sense include:

Why not just always use Apex? Because code must be maintained. Someone must understand it later, write test classes, debug deployments, and update it when the business changes. Unnecessary code becomes technical debt very quickly. Use Apex only when declarative tools stop being practical.

Decision Framework

Instead of guessing every time, you can follow a clear order:

1. Are you preventing incorrect data? → Validation Rule

2. Are you automating a business process? → Flow

3. Is the requirement too complex or performance-heavy? → Apex Trigger

Many Salesforce orgs become slow because admins skip the first step and immediately build a Flow. Over time, dozens of flows begin reacting to the same record save, and troubleshooting becomes painful.Often, a single Validation Rule would have solved the problem faster and cleaner.

Final Thoughts

Good Salesforce architecture is not about using the most powerful tool available. It is about using the simplest tool that correctly solves the problem.

Once you start thinking this way, designing solutions becomes much easier and your org becomes faster, cleaner, and easier for the next admin (or future you) to maintain.