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Best Open Source SIEM Alternatives to Splunk in 2026

Open source SIEM tools provide cost-effective security monitoring with full transparency into detection logic and data handling.

3 Open Source SIEM Tools, side by side

ToolDeploymentPricing modelOpen source
Elastic SecurityCloud + Self-hostedResource-based (nodes/capacity)Yes
GraylogCloud + Self-hostedPer-node licensing (Operations and Security tiers)Yes
WazuhCloud + Self-hostedOpen SourceYes

By eliminating per-GB ingest costs and allowing self-hosted deployments, these tools give security teams complete control over their SIEM infrastructure. They are ideal for organizations that want to avoid vendor lock-in, customize detection rules, and reduce the escalating costs of enterprise SIEM platforms like Splunk.

By use case

Our read on which tool suits which job. Editorial, not paid, and separate from the listing below.

Open source at scale

Elastic Security

The most capable open-source SIEM alternative to Splunk, offering unified SIEM, EDR, and cloud security on the ELK Stack. Best for teams that want enterprise-grade detection without per-GB ingest costs and can manage Elasticsearch clusters.

Open source, Cloud, Self-hosted

Approachable log management

Graylog

A more approachable open-source option with an intuitive interface and powerful pipeline processing. Best for teams that need centralized log management with SIEM capabilities at a fraction of Splunk's cost and complexity.

Open source, Cloud, Self-hosted

Free full-stack security

Wazuh

The most comprehensive free open-source security platform, combining SIEM, XDR, and compliance monitoring in one agent-based solution. Best for organizations wanting full-stack security visibility with zero licensing costs.

Open source, Cloud, Self-hosted

Elastic Security

SIEM & Security Analytics
Best fit for

Teams wanting open-source flexibility with enterprise SIEM capabilities and no per-GB ingest pricing

Elastic Security is a unified security solution built on the Elastic (ELK) Stack that combines SIEM, endpoint security, and cloud security into a single platform. It leverages Elasticsearch for fast search and analytics at scale, provides pre-built detection rules aligned with MITRE ATT&CK, and offers free and open core functionality that makes it accessible to organizations of all sizes.

Pricing

Free 14-day trial; no flat published price. Elastic Cloud Hosted is resource/pay-as-you-go; Serverless Security is usage-based from ~$0.09/GB ingest + ~$0.017/GB/mo retention (Essentials), ~$0.11/$0.019 (Complete); enterprise/self-managed via contact sales.

Resource-based (nodes/capacity)

Deployment

Cloud, Self-hosted, Open source

Standards & certifications

SOC 2, ISO 27001, PCI DSS

Visit Elastic SecurityView listing

Graylog

SIEM & Security Analytics
Best fit for

Teams needing cost-effective log management with SIEM capabilities and an intuitive user experience

Graylog is an open-source log management and SIEM platform designed for collecting, indexing, and analyzing log data at scale. Its centralized log management approach combined with security analytics capabilities makes it a cost-effective alternative to enterprise SIEMs. Graylog offers a streamlined, intuitive interface and a powerful pipeline processing engine for data enrichment and normalization.

Pricing

Free source-available "Open" tier; paid plans Enterprise from $15,000/yr, Security and API Security from $18,000/yr (consumption-based, contact sales for a quote)

Per-node licensing (Operations and Security tiers)

Deployment

Cloud, Self-hosted, Open source

Visit GraylogView listing

Wazuh

SIEM & Security Analytics
Best fit for

Organizations wanting a free, comprehensive SIEM/XDR platform with strong compliance capabilities

Wazuh is a free, open-source security platform that provides unified XDR and SIEM protection. It offers log analysis, intrusion detection, file integrity monitoring, vulnerability detection, and compliance monitoring across on-premises and cloud workloads.

Pricing

Free (Open Source)

Open Source

Deployment

Cloud, Self-hosted, Open source

Visit WazuhView listing

Comparisons

Datadog Security vs Elastic Security

Choose Datadog Security if seamless integration of security and observability is your priority and devSecOps teams that ...

Read Comparison

Datadog Security vs Graylog

Choose Datadog Security if seamless integration of security and observability is your priority and devSecOps teams that ...

Read Comparison

Elastic Security vs LogRhythm

Choose Elastic Security if open-source core with no ingest-based pricing is your priority and teams wanting open-source ...

Read Comparison

Splunk vs Graylog

Choose Graylog if you need an affordable, intuitive log management and SIEM solution that your team can learn quickly. C...

Read Comparison

Wazuh vs Splunk

Choose Wazuh if licence cost matters most and you have the skills to run it, or want a managed service at a fixed monthl...

Read Comparison

Wazuh vs Graylog

Choose Wazuh if you want threat detection on the endpoints themselves, with every feature free. Choose Graylog if your p...

Read Comparison

Shortlists

Editorial lists and deep dives covering these tools.

Frequently Asked Questions

For many organizations, yes. Elastic Security in particular has matured significantly and provides SIEM, endpoint detection, and cloud security in a single platform. While Splunk still leads in query flexibility (SPL), app ecosystem breadth, and managed SOAR, open source SIEMs can handle core security monitoring, threat detection, and compliance at a dramatically lower cost. The tradeoff is that you need operational expertise to deploy and maintain the infrastructure.

Organizations typically report 50-80% cost reductions when moving from Splunk to open source SIEMs like Elastic Security or Graylog. The savings come primarily from eliminating per-GB ingest licensing, which is Splunk's largest cost driver at scale. However, factor in the operational cost of managing your own infrastructure, hiring or training Elasticsearch administrators, and the time investment in building custom detection content.

Elastic Security is the more feature-complete SIEM, offering detection rules, EDR, cloud security posture management, and machine learning anomaly detection. Graylog excels at log management with an intuitive interface and powerful pipeline processing but has less mature security-specific features. Choose Elastic Security for a full SIEM replacement; choose Graylog for cost-effective log management with basic SIEM capabilities.

Running an open source SIEM requires skills in Linux administration, the underlying data store (Elasticsearch for Elastic Security, MongoDB and OpenSearch for Graylog), cluster management, capacity planning, and security content development. Your team should be comfortable writing detection rules, managing data pipelines, and troubleshooting distributed systems. Many organizations start with managed cloud offerings (Elastic Cloud, Graylog Cloud) to reduce the operational burden.

View all SIEM & Security Analytics tools

About this listing

Open Source SIEM Tools tools, compared on public information. The comparison table and the full entries follow our editorial order, with any paid Featured listing shown first and labelled. How we work →