Prometheus

Prometheus is an open-source systems and service monitoring system, originally built at SoundCloud and now a Cloud Native Computing Foundation (CNCF) graduated project. It scrapes metrics from configured HTTP targets at intervals, stores them in a custom on-disk time series database (TSDB), evaluates rule expressions written in PromQL, and triggers alerts through external Alertmanagers.

This wiki covers the github.com/prometheus/prometheus repository: a single Go module that builds two binaries (prometheus and promtool), a React-based web UI, and a large collection of service discovery, storage, and protocol-translation packages.

What this repository contains

The repo at github.com/prometheus/prometheus produces:

• prometheus — the main server binary. It scrapes targets, ingests samples into the TSDB or the agent WAL, evaluates rules, and serves the HTTP API and UI. Source: cmd/prometheus/main.go.
• promtool — a CLI for validating configuration, querying a server, debugging the TSDB, running rule unit tests, and importing OpenMetrics data. Source: cmd/promtool/main.go.
• The TSDB library (tsdb/) — a self-contained time series database used by the Prometheus server and reusable by other projects.
• The PromQL engine (promql/) — a parser, AST, and evaluator for PromQL queries.
• A library of service discovery plugins (discovery/) for Kubernetes, AWS, Consul, DNS, Azure, GCE, and ~25 other systems.
• The remote write/read subsystem (storage/remote/) for shipping samples to long-term storage and ingesting from compatible senders.
• The React web UI (web/ui/) — both the new Mantine-based UI and the legacy 2.x UI.

Where to start

If you want to...	Read this
Understand the high-level architecture	Architecture
Build and run Prometheus locally	Getting started
Learn project-specific terminology	Glossary
Submit a PR or fix a bug	How to contribute
Understand the storage engine	TSDB
Learn how scraping works	Scrape
Understand PromQL evaluation	PromQL
Add or modify a service discovery	Discovery
See current codebase statistics	By the numbers
Read the project history	Lore

Project facts

Attribute	Value
Current version	3.11.2 (April 2026), see VERSION
Language	Go (server, library, tooling) + TypeScript/React (UI)
Go module	github.com/prometheus/prometheus (Go 1.25+, see go.mod)
License	Apache 2.0 (LICENSE)
First commit	24 November 2012
Governance	CNCF graduated project; a team of general and area maintainers
Build system	make build driven by Makefile and Makefile.common

See Maintainers for the current owner list and Reference: Dependencies for the third-party landscape.