Vercel Flags now supports JSON values

You can now store JSON values in Vercel Flags, extending the existing support for boolean, string, and number values. This allows you to collapse what used to take several related flags into a single feature flag.

For example, to A/B test how a different model performs, you can now define a single model flag. This allows you to manage one flag that serves the full object rather than managing ai_model, ai_temperature, and ai_max_tokens separately:

// Variant A
{
  "id": "claude-sonnet-4-6",
  "temperature": 0.7, 
  "maxTokens": 1024,
  "systemPrompt": "You are a helpful shopping assistant."
}

// Variant B
{
  "id": "claude-opus-4-6",
  "temperature": 0.8, 
  "maxTokens": 2048,
  "systemPrompt": "You help with shopping."
}

Use Vercel Flags to progressively route traffic to a new model, A/B test, or quickly switch models in case a provider is having issues.

Try it out or learn more about Vercel Flags.