Prometheus 3.0‑beta Released: New UI, Remote Write 2.0, OpenTelemetry Support, and Other Major Changes

Prometheus has announced the release of version 3.0‑beta, available for download from the official GitHub releases page. Users are advised not to run the beta in critical production environments but are encouraged to test and report any issues.

The most noticeable change is a brand‑new default UI that replaces the old interface with a modern, less cluttered design, including a tree‑view similar to PromLens. The new UI can be temporarily disabled via the old-ui feature flag, and any bugs should be reported on GitHub.

Remote Write 2.0

Remote Write 2.0 improves the previous protocol by adding native support for metadata, exemplars, creation timestamps, and native histograms. It also reduces compression overhead through string interning, lowering CPU usage during compression and decompression.

OpenTelemetry Support

Prometheus 3.0 aims to be the default storage backend for OpenTelemetry metrics, adding several enhancements that make it a better fit for OpenTelemetry data.

UTF‑8

All metric and label names and values now accept any valid UTF‑8 characters, as in the 2.x series. Users must ensure their metric generators emit UTF‑8; otherwise, names will be escaped using the traditional underscore method. Queries can retrieve UTF‑8 metrics using the new quoted syntax or by manually specifying the __name__ label. Most Go client libraries already support UTF‑8.

OTLP Ingestion

Prometheus can be configured as a native receiver for the OTLP Metrics protocol, exposing an /api/v1/otlp/v1/metrics endpoint.

Native Histograms

Native histograms are a new, more efficient histogram type that uses exponentially growing bucket boundaries and does not require pre‑defined bucket configurations. They are experimental, disabled by default, and can be enabled with --enable-feature=native-histograms . Some aspects, such as text format and query functions, are still under design.

Other Major Changes

Removed feature flags (now enabled by default): promql-at-modifier , promql-negative-offset , remote-write-receiver , no-scrape-default-port , new-service-discovery-manager .

Range selection is now left‑open, right‑closed, preventing unexpected extra points.

Proxy mode is now stable and has its own configuration flag instead of being a feature flag.

The announcement concludes with a reminder to follow the official blog for more details and to stay updated on future releases.