Practical guides

Feature flag guide

Feature flags, environments, rollouts, kill switch, audit trail and experimentation.

Last updated: May 22, 20268-14 minBeginner to intermediate
Start free See pricingMethodology

Feature flags vs A/B tests

An A/B test measures the performance of experiences. A feature flag controls who receives a new feature, in which environment and at what rollout percentage. Testvoy connects these worlds so product and engineering teams can move between safe rollout and measured experimentation.

Development, staging and production environments

Staged rollout by percentage

Fast rollback with kill switch

Approval gates and audit trail

Environment-specific SDK keys

Flag rollout flow
DevStagingProd
Environment, rollout, approval and kill switch are managed in one operations surface.

Safe rollout checklist

A flag should not be treated as only an on/off switch. New features ship more safely when rollout plan, measurement goal, owner, rollback criteria and audit history are clear upfront.

  • Is the owner and approver clear?
  • Is the SDK key correct in staging?
  • Did rollout start with a small audience?
  • Was the kill switch tested?
  • Is a decision goal or health metric connected?

Implementation example

For Feature flag guide, the safest approach is to start with a small verifiable scenario, then validate the setting in Testvoy through QA and reporting. The example fields below clarify what to enter in a real project.

  1. 01

    Choose the project

  2. 02

    Create the setting or rule with a clear name

  3. 03

    Enter an example URL/event/segment value

  4. 04

    Verify with preview or verifier

  5. 05

    Check the result in reporting

Example fields
Name: Feature flag guide
Project: storefront-production
URL: /pricing
Goal: signup_completed
Audience: all visitors

Practical scenario

A growth team changes CTA copy on the pricing page, connects signup_started and signup_completed goals, then reads Google Ads and returning visitor segments separately. If the result is promising, they share a report link with the client or leadership.

Common mistakes

Most mistakes come from wrong project keys, overly broad selectors, missing goals, staging/prod mixups, early decisions on small samples or skipping mobile QA.

Naming an experiment 'test'

Launching without a goal

Deciding on total CVR only

Sending screenshots instead of shareable reports

Frequently asked questions

Who is Feature flag guide for?

Marketing, growth, product and developer teams can use the same guide at different depths.

Do I need a developer?

Not for basic visual changes and report reading; SDK, custom events, custom JS or enterprise security benefit from technical support.

How do I know it worked?

Verifier, recent events, preview, QA checklist and report warnings show setup and experiment health.

What is the common mistake?

Wrong project keys, missing goals, fragile selectors, early decisions on small samples and skipped mobile QA are common.

Docs

Try this guide in the app

Finish setup, create your first experiment and read the report with cleaner data in Testvoy.