Always-on tracing for production and preview traffic

Vercel has launched Always-on tracing for production and preview traffic in beta. Unlike previous session tracing, which only captured developer browser requests, this feature continuously samples real user traffic to assist with debugging.

Users can control the collection scope via sampling rules. You can set trace ratios for each environment (all, production, preview) and limit the scope to specific path prefixes such as /checkout. Nothing is collected until rules are added, so you only pay for what you choose.

Infrastructure and external fetch spans are captured automatically. To add framework and custom spans, you must instrument your app with @vercel/otel. Traces can be viewed in the Logs dashboard or retrieved using the vercel traces get <request-id> command.

Pricing and policies are as follows:

• Cost: $0.50 per million spans
• Retention period: Follows runtime log retention (Hobby: 1 hour, Pro: 1 day, Enterprise: 3 days)
• Availability: Available to teams on all plans