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OpenCost

Open-source Kubernetes cost monitoring (CNCF)

open sourceupdated Apr 21, 2026

OpenCost is a CNCF-certified open-source tool for real-time Kubernetes cost monitoring that maps cloud spend directly to namespaces, deployments, pods, and labels. It provides granular cost allocation across teams and projects without vendor lock-in, supporting AWS, GCP, Azure, and on-premises clusters as the industry standard for open-source FinOps visibility in cloud-native environments.

OpenCost provides real-time cost monitoring for Kubernetes clusters by combining cloud billing data with cluster resource utilization metrics. The platform maps costs to individual namespaces, deployments, pods, containers, and custom labels, giving teams precise visibility into how cloud spend is distributed across applications, teams, and environments. This granular allocation enables accurate chargeback and showback without relying on estimates.

As a CNCF-certified project, OpenCost adheres to the Kubernetes cost monitoring standards defined by the cloud-native community. It supports all major cloud providers including AWS, GCP, and Azure, as well as on-premises Kubernetes distributions. The tool integrates with Prometheus for metrics collection and Grafana for visualization, fitting naturally into existing cloud-native observability stacks.

OpenCost is completely free and open-source, making it the accessible foundation for any organization's FinOps practice. Multi-cloud support ensures consistent cost visibility even in hybrid environments. The active community contributes new cloud provider integrations, cost allocation models, and reporting capabilities. Enterprise teams often use OpenCost as the data foundation, layering commercial optimization tools on top for automated action.

Pricing

Free and open-source (Apache 2.0)

Platforms

Kubernetes, AWS, GCP, Azure, Prometheus, Grafana

Categories

Tags

Use Cases

CAST AI logo

CAST AI

Autonomous Kubernetes cost optimization

CAST AI automates Kubernetes cost optimization by analyzing workloads in real time and taking direct action on clusters, including right-sizing pods, selecting optimal instance types, and leveraging spot instances automatically. The platform achieves up to 60% cost reduction without human intervention, offering a free cluster audit that identifies savings opportunities before any commitment.

freemium
Vespa logo

Vespa

Hybrid search and ML ranking engine at scale

Vespa is an open-source serving engine with 6K+ GitHub stars for hybrid search combining vector similarity, BM25 text ranking, and structured filtering in a single query. Built by Yahoo for web-scale, it handles billions of documents with millisecond latency. Features real-time indexing, ML model serving, tensor computation, and ACID-compliant writes. Supports custom ranking models, query federation, and geographic search. Used for recommendation systems, personalization, and RAG.

Open Source
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RAGFlow

Deep document understanding RAG engine

RAGFlow is an open-source RAG engine with 76K+ GitHub stars that provides deep document understanding for building knowledge-based AI applications. Optimizes chunking for 20+ document types including PDFs, Word docs, presentations, and images using layout-aware parsing. Features template-based chunking strategies, citation with source references, multi-recall retrieval combining keyword and semantic search, and a visual knowledge base management interface with drag-and-drop document upload.

Open Source

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Used in Stacks

Comparisons

Kubecost vs OpenCost — Commercial K8s Cost Platform vs CNCF Open-Source Cost Allocation

Kubecost and OpenCost share deep roots since Kubecost contributed the OpenCost project to the CNCF, but they serve different audiences and offer different capability levels. Kubecost provides a full commercial cost management platform with multi-cluster aggregation, savings recommendations, and budget alerts. OpenCost delivers the core cost allocation engine as free open-source software for teams that need visibility without enterprise features.

KubecostOpenCost

CAST AI vs Sedai vs OpenCost — Kubernetes Cost Optimization & FinOps Tools Compared

Kubernetes enables powerful orchestration but makes cost management deceptively complex. Shared clusters blur resource ownership, dynamic scaling changes cost profiles hourly, and overprovisioned resource requests silently waste 20-40% of cloud spend. This comparison examines three distinct approaches: CAST AI for automated infrastructure optimization with instant savings, Sedai for autonomous cloud management powered by reinforcement learning, and OpenCost as the CNCF open-source standard for Kubernetes cost visibility and allocation.

CAST AISedaiOpenCost

FAQ

What is OpenCost?

OpenCost is a CNCF-certified open-source tool for real-time Kubernetes cost monitoring that maps cloud spend directly to namespaces, deployments, pods, and labels. It provides granular cost allocation across teams and projects without vendor lock-in, supporting AWS, GCP, Azure, and on-premises clusters as the industry standard for open-source FinOps visibility in cloud-native environments.

Is OpenCost free?

Yes — OpenCost is open source and free to use. Free and open-source (Apache 2.0)

Is OpenCost open source?

Yes — OpenCost is open source.

What are the best OpenCost alternatives?

The top editor-verified OpenCost alternatives are CAST AI, Vespa, RAGFlow.