Open Source Splunk Alternatives in 2026

Why Teams Are Leaving Splunk

Splunk dominates enterprise log analytics, but its pricing pushes teams away. Workload pricing starts around $1,800/year for 1 GB/day ingest. At 10 GB/day, expect $15,000-20,000/year. At 100 GB/day, you're looking at $100,000-150,000/year — and that's before premium add-ons like Enterprise Security (SIEM), IT Service Intelligence, or premium support tiers. Cisco's 2024 acquisition of Splunk for $28 billion adds strategic uncertainty: licensing changes, product direction shifts, and deeper integration into Cisco's enterprise bundle are all on the table.

The open source log management ecosystem has matured dramatically. Tools like Graylog, OpenSearch, and Grafana Loki now handle terabytes of daily log ingest with production-grade reliability. SIEM capabilities that once justified Splunk's cost premium are available in Wazuh at zero licensing cost. Cloud-native search engines like Quickwit deliver sub-second query performance on object storage at a fraction of the infrastructure cost.

This roundup covers five open source alternatives that cover Splunk's core use cases: centralized log management, full-text search, security monitoring (SIEM), alerting, and dashboards.

TL;DR

Graylog is the most direct Splunk replacement for log management — centralized ingest, powerful search, dashboards, and alerting in one platform. Wazuh is the pick if SIEM and security monitoring are your primary use case. Grafana Loki wins on cost-efficiency for teams already running the Grafana stack.

Key Takeaways

Graylog offers the closest feature parity to Splunk's log management — pipelines, extractors, dashboards, and alerting built in
OpenSearch is the most scalable option — handles petabyte-scale log data with full-text search and visualization via OpenSearch Dashboards
Wazuh replaces Splunk Enterprise Security (SIEM) — threat detection, compliance reporting, and vulnerability assessment at zero license cost
Quickwit is purpose-built for cloud-native log search on object storage — dramatically lower storage costs than Elasticsearch-based solutions
Grafana Loki is the lightest option — index-free log aggregation that pairs with Prometheus and Grafana for unified observability
Cost savings are substantial — self-hosting at 50 GB/day costs $3,000-8,000/year in infrastructure vs $60,000-100,000/year for Splunk

Quick Comparison

Feature	Graylog	OpenSearch	Wazuh	Quickwit	Grafana Loki
License	SSPL / Apache 2.0	Apache 2.0	GPL-2.0	AGPL-3.0	AGPL-3.0
Self-Host Difficulty	Medium	Medium-High	Medium	Low-Medium	Low
Docker/K8s Support	Docker, K8s	Docker, K8s, Helm	Docker, K8s	Docker, K8s	Docker, K8s, Helm
Search Language	Graylog QL + Lucene	DQL + PPL + SQL	Wazuh QL	Lucene-like	LogQL
SIEM Capability	Basic (paid tier)	Via Security Plugin	Full (native)	None	None
Alerting	Built-in	Built-in	Built-in	Via Grafana	Via Grafana
Data Retention	Configurable (index rotation)	Index lifecycle mgmt	Configurable	S3/GCS lifecycle	Configurable (object storage)
Active Development	Active (Graylog Inc.)	Active (AWS + community)	Active (Wazuh Inc.)	Active (Quickwit Inc.)	Active (Grafana Labs)

Pricing: Splunk vs Self-Hosted

Splunk's costs scale with ingest volume. Self-hosted costs scale with infrastructure — which grows much slower.

Daily Ingest	Splunk Cloud	Splunk Enterprise	Self-Hosted (Graylog/OpenSearch)	Self-Hosted (Loki)
1 GB/day	$1,800/year	$1,800/year	$600-1,200/year (VPS)	$300-600/year (VPS)
10 GB/day	$15,000-20,000/year	$12,000-18,000/year	$2,400-4,800/year	$1,200-2,400/year
50 GB/day	$60,000-100,000/year	$50,000-80,000/year	$6,000-12,000/year	$3,600-7,200/year
100 GB/day	$100,000-150,000/year	$80,000-120,000/year	$12,000-24,000/year	$6,000-12,000/year
500 GB/day	$400,000+/year	$300,000+/year	$36,000-72,000/year	$18,000-36,000/year

Self-hosted costs = compute + storage infrastructure + engineer time for operations. Splunk costs = license/subscription only, excluding infrastructure for Enterprise deployments.

Loki's cost advantage comes from its architecture: it indexes only labels (metadata), not log content, and stores compressed log chunks on cheap object storage (S3, GCS, MinIO). Graylog and OpenSearch use Elasticsearch-style full-text indexing, which requires more disk I/O and storage but delivers faster ad-hoc search across log content.

Graylog

The most direct Splunk replacement for centralized log management.

GitHub: 7,300+ stars
Stack: Java, MongoDB, OpenSearch/Elasticsearch backend
License: SSPL (server), Apache 2.0 (some components)
Deploy: Docker, DEB/RPM packages, Kubernetes

Graylog is purpose-built for log management. It accepts logs via Syslog, GELF, Beats, and raw TCP/UDP inputs, processes them through configurable pipelines and extractors, and makes them searchable through a web interface with dashboards and alerts. If you've used Splunk's search and reporting interface, Graylog's workflow feels familiar.

Standout features:

Processing pipelines with rule-based routing, enrichment, and transformation
Extractors for parsing unstructured logs into structured fields
Stream-based routing to direct logs to different indices and retention policies
Role-based access control with LDAP/AD integration
Sidecar agent management for deploying log collectors (Filebeat, Winlogbeat) across fleets
Content packs for pre-built dashboards and extractors (similar to Splunk apps)

Graylog's free tier (Open) covers log management, search, and dashboards. The paid tiers (Operations and Security) add anomaly detection, SIEM correlation, and enterprise support. For pure log management, the open source version is fully capable.

# docker-compose.yml — Graylog with OpenSearch
services:
  mongodb:
    image: mongo:6.0
    volumes:
      - mongo_data:/data/db

  opensearch:
    image: opensearchproject/opensearch:2
    environment:
      - discovery.type=single-node
      - DISABLE_SECURITY_PLUGIN=true
    volumes:
      - os_data:/usr/share/opensearch/data

  graylog:
    image: graylog/graylog:6.1
    depends_on:
      - mongodb
      - opensearch
    ports:
      - "9000:9000"   # Web UI
      - "1514:1514"   # Syslog TCP
      - "12201:12201" # GELF TCP
    environment:
      - GRAYLOG_HTTP_EXTERNAL_URI=http://127.0.0.1:9000/

Best for: Teams replacing Splunk's core log management — ingest, search, dashboards, and alerting. Organizations with mixed infrastructure (Linux, Windows, network devices) sending logs via Syslog.

OpenSearch

Scalable full-text search and analytics, community-driven.

GitHub: 9,800+ stars
Stack: Java (OpenSearch), React (Dashboards)
License: Apache 2.0
Deploy: Docker, Helm, RPM/DEB, Kubernetes Operator

OpenSearch is AWS's fork of Elasticsearch and Kibana, created after Elastic changed Elasticsearch's license in 2021. It provides the same distributed search and analytics engine, with OpenSearch Dashboards replacing Kibana for visualization. For organizations that built their log infrastructure on the ELK stack, OpenSearch is a license-safe continuation of that architecture.

Standout features:

Full-text search with Lucene-based indexing — fast ad-hoc queries across billions of log lines
OpenSearch Dashboards for visualization, saved searches, and alert management
Index lifecycle management for automated rollover and deletion based on age or size
Security plugin with fine-grained access control, audit logging, and encryption
Anomaly detection plugin using machine learning for automated pattern recognition
SQL and PPL (Piped Processing Language) query support alongside DQL
Cross-cluster replication for disaster recovery and geographic distribution

OpenSearch handles petabyte-scale data when deployed as a multi-node cluster. The tradeoff is operational complexity: cluster management, shard allocation, JVM tuning, and index optimization require dedicated expertise. At smaller scale (under 50 GB/day), a 3-node cluster runs comfortably on modest hardware.

Best for: Organizations already running Elasticsearch/Kibana, teams needing petabyte-scale full-text search, environments where Apache 2.0 licensing is required.

Wazuh

Open source SIEM and security monitoring — the Splunk Enterprise Security replacement.

GitHub: 11,500+ stars
Stack: C, Python, OpenSearch/Elasticsearch backend
License: GPL-2.0
Deploy: Docker, OVA, AMI, Kubernetes, packages

Wazuh is the open source answer to Splunk Enterprise Security. It combines host-based intrusion detection (HIDS), log analysis, vulnerability assessment, and compliance reporting in a single platform. While Graylog and OpenSearch focus on general log management, Wazuh is specifically built for security operations.

Standout features:

Real-time threat detection with 3,000+ built-in detection rules (MITRE ATT&CK mapped)
File integrity monitoring (FIM) — detect unauthorized changes to critical system files
Vulnerability assessment — scan agents for known CVEs and report remediation priority
Compliance dashboards for PCI DSS, HIPAA, GDPR, NIST 800-53, and SOC 2
Active response — automatically block IPs, kill processes, or quarantine files on detection
Agent-based architecture — deploy lightweight agents on Linux, Windows, macOS endpoints
Integration with OpenSearch Dashboards for visualization and investigation

Wazuh's agent-based model provides deeper host visibility than log-only approaches. Agents report file changes, running processes, open ports, installed packages, and system configuration — giving security teams the context needed to investigate alerts. Splunk Enterprise Security costs $20,000-75,000/year on top of base Splunk licensing; Wazuh provides comparable SIEM functionality at zero license cost.

Best for: Security teams replacing Splunk Enterprise Security, organizations needing compliance reporting (PCI, HIPAA, SOC 2), teams wanting host-based intrusion detection alongside log analysis.

Quickwit

Cloud-native search engine built for logs on object storage.

GitHub: 8,500+ stars
Stack: Rust
License: AGPL-3.0
Deploy: Docker, Kubernetes, binary

Quickwit takes a fundamentally different approach to log search. Instead of maintaining expensive local disk indices like Elasticsearch or OpenSearch, Quickwit indexes directly to object storage (S3, GCS, Azure Blob, MinIO). This decouples compute from storage, making it possible to search terabytes of logs without provisioning proportional local disk. Storage costs drop by 5-10x compared to Elasticsearch for the same data volume.

Standout features:

Sub-second search on object storage — no local SSDs required for the data tier
Native Kafka and Kinesis ingest — stream logs directly without an intermediate shipper
OpenTelemetry-native — accepts OTLP traces and logs directly
Elasticsearch-compatible API — drop-in replacement for many Elasticsearch query patterns
Jaeger and Grafana integrations — use existing dashboards and trace UIs
Schemaless indexing — ingest JSON logs without pre-defining a schema
Designed for Kubernetes — stateless search nodes scale horizontally

Quickwit is newer than the other tools in this roundup, but its Rust-based engine and object-storage-first architecture make it compelling for cloud-native environments where storage costs dominate. Teams running in AWS or GCP save significantly by storing logs in S3/GCS instead of on EBS volumes or persistent disks.

# quickwit.yaml — minimal configuration
version: 0.8
node_id: searcher-1
metastore_uri: s3://my-bucket/quickwit/indexes
default_index_root_uri: s3://my-bucket/quickwit/indexes

Best for: Cloud-native environments where storage cost is the primary concern, teams already using Kafka for log streaming, organizations wanting Elasticsearch-compatible search on object storage.

Grafana Loki

Lightweight log aggregation designed for the Grafana ecosystem.

GitHub: 24,500+ stars
Stack: Go
License: AGPL-3.0
Deploy: Docker, Helm, Kubernetes, binary

Grafana Loki takes the most opinionated approach in this roundup: it deliberately does not index log content. Instead, Loki indexes only metadata labels (like job, namespace, pod, level) and stores compressed log chunks on object storage. This makes Loki dramatically cheaper to operate than Elasticsearch-based solutions, at the cost of slower ad-hoc full-text search across unindexed fields.

Standout features:

Label-based indexing — storage costs 10-20x lower than Elasticsearch for the same log volume
LogQL query language — Prometheus-like syntax for filtering and aggregating logs
Native Grafana integration — query logs alongside metrics and traces in the same dashboards
Multi-tenancy built in — isolate log data by team or environment
Promtail, Alloy, and Fluentd/Fluent Bit as log shippers
S3, GCS, Azure Blob, and MinIO as storage backends
Scales horizontally with microservices deployment mode for high-volume environments

Loki's design philosophy mirrors Prometheus: simple, cost-effective, and tightly integrated with Grafana. If your team already runs Prometheus + Grafana for metrics, adding Loki for logs is the natural extension — same query paradigm, same dashboards, same alerting system.

The tradeoff is search flexibility. Splunk and OpenSearch let you search any field in any log line instantly because they index everything. Loki requires you to filter by labels first, then grep through matching log streams. For known queries (e.g., "show me errors from the payment service in the last hour"), Loki is fast. For exploratory analysis across all logs without knowing which labels to filter on, Elasticsearch-based tools are faster.

For the complete Grafana + Prometheus + Loki deployment guide, see how to set up a self-hosted observability stack with Grafana, Prometheus, and Loki.

Best for: Teams already using Grafana and Prometheus, cost-conscious environments with high log volume, Kubernetes-native deployments where label-based filtering aligns with how logs are structured.

When to Use Which

The right choice depends on your primary use case, existing infrastructure, and team expertise.

Replace Splunk's log management (search, dashboards, alerts): Pick Graylog. It's the most direct functional replacement — same workflow of ingest, parse, search, alert. Familiar to Splunk users, lower operational complexity than OpenSearch, and the free tier covers core log management. If you need more scale or are already running Elasticsearch, pick OpenSearch instead.

Replace Splunk Enterprise Security (SIEM): Pick Wazuh. No other open source tool matches its breadth of security monitoring: detection rules, vulnerability scanning, compliance reporting, and host-based intrusion detection. Pair Wazuh with Graylog or OpenSearch if you also need general-purpose log management beyond security events.

Minimize storage costs for high-volume logs: Pick Grafana Loki or Quickwit. Both store data on cheap object storage. Loki is simpler to operate and integrates natively with Grafana. Quickwit offers faster full-text search and an Elasticsearch-compatible API. At 100+ GB/day, storage architecture drives cost more than compute — these two tools are designed for that reality.

Already running the Grafana stack: Pick Grafana Loki. Adding Loki to an existing Prometheus + Grafana deployment is straightforward — same ecosystem, same query patterns, same dashboards. See the complete observability stack guide for how Loki fits alongside Prometheus, Tempo, and Grafana.

Need Elasticsearch-compatible APIs: Pick OpenSearch. If your existing tooling, dashboards, or integrations rely on Elasticsearch APIs, OpenSearch is the drop-in replacement with Apache 2.0 licensing. Migration from Elasticsearch to OpenSearch requires minimal changes.

Combined stack for large organizations: Many teams run multiple tools. A common pattern: Wazuh for security monitoring and SIEM, Graylog or OpenSearch for operational log management, and Grafana Loki for application-level log aggregation. Each tool handles what it does best, with logs routed to the appropriate system based on source and purpose.

For broader observability beyond log management — metrics, traces, APM, and uptime monitoring — see best open source alternatives to Datadog and best open source monitoring tools. For a hands-on guide to deploying OpenObserve as a lightweight log management platform, see how to self-host OpenObserve. For the full category index of open source SaaS alternatives, see open source alternative for every SaaS category.

The SaaS-to-Self-Hosted Migration Guide (Free PDF)