Stoplight 6.0 Roadmap - Breaking Changes & Feedback

[bolshakov]

We're planning Stoplight 6.0 somewhere in 2026 with three breaking changes that fix long-standing design issues.

• Read the full roadmap on my blog →

What's Changing

1. Configuration Conflict Prevention

• Same circuit name must have same configuration
• #withand with_* famility of methods removed--encouraged dangerous config mutation
• Raises ConfigurationError immediately on conflicts
• Enables ~5x performance improvement through safe caching
• Migration: Audit lights for config conflicts -

2. Cleaner Configuration API

• Behavioral settings: Stay at light level (threshold, window_size)
• Observability: Move to global (notifiers, error_notifier)
• Runtime: Move to #run call (tracked_errors, fallback)
• Migration: Mechanical changes, deprecation warnings in 5.x

Timeline

• Q4 2025: Deprecation warnings in 5.x releases
• 2026: 6.0 release
• Gives you enougcht time to test and plan

Questions for You

1. Are we missing legitimate use cases for #with? Some pattern where light mutation actually makes sense?
2. Will moving notifiers to global config break your setup? Are you doing something clever with per-circuit notifiers?
3. Does the bundling make sense? Or would you rather take these changes separately (multiple upgrades over the year)?

Your real-life experience matters more than theoretical design. Share your thoughts here--especially if something in this roadmap would break your setup or if we're missing an important use case.

Updated 20 Feb 2026: Updated timeline