Both collect and search huge volumes of machine data for observability and security, so the choice comes down to how you want to run and pay for it. Elastic offers Elastic Cloud Serverless, Elastic Cloud Hosted and self-managed Elasticsearch, with source code you can use under an open source AGPL licence. Splunk, now part of Cisco, offers Splunk Cloud Platform and Splunk Enterprise for on-premises and even air-gapped sites, with several ways to pay and unlimited users.
Both are big names in log analytics, so I read Elastic's plans, observability and licensing pages and Splunk's plans, Enterprise trial and about pages to set out the practical differences.
Elastic and Splunk side by side
| Elastic | Splunk | |
|---|---|---|
| Ownership | Elastic | Part of Cisco |
| Managed option | Elastic Cloud Serverless and Hosted | Splunk Cloud Platform |
| Self-managed option | Self-managed Elasticsearch, locally or on Kubernetes | Splunk Enterprise, private cloud, on premises or air-gapped |
| Licence for self-managed | SSPL, Elastic License or AGPL | Paid, after a 60-day free trial |
| Ways to pay | Serverless or hosted plans | Activity-based, ingest or workload models |
| Security tools | SIEM, agentic SOAR, XDR and endpoint | SIEM, SOAR, UEBA |
| Free trial | Free trials for cloud options | Splunk Enterprise free for 60 days, no credit card |
How you pay is the big difference
Splunk gives you a choice of models. Its plans page says Splunk Cloud Platform can be bought on activity-based, ingest or workload models, all with unlimited users, and Splunk Enterprise on ingest or workload models. Cloud Flex lets you move spend across Splunk products as your needs change, and eligible Cisco telemetry counts at a reduced, weighted ingest rate, a perk for companies already on Cisco gear.
With Elastic, the choice is about how much you'd like to run yourself. Serverless means zero operational load, Hosted means you pick the cloud and keep control, and self-managed means you download and run Elasticsearch yourself. Since a licence change in 2024, Elastic says the source is available under the open source AGPL as well as SSPL and the Elastic License.
Where Elastic stands out
Elastic builds observability and security on top of its search engine. Its observability tools include log analytics with Search AI, AI agents that detect and investigate issues across your stack and LLM observability for monitoring AI apps. On the security side it offers SIEM, agentic SOAR that automates alert triage and response with Elastic Workflows so you don't need a separate SOAR tool, and XDR and endpoint security.
For the open source side of Elastic's story, our Elasticsearch vs OpenSearch guide explains the OpenSearch fork.
Where Splunk stands out
Splunk says it's helped organisations explore their machine data since 2003, like spelunkers in a cave, and it now describes itself as supercharged by Cisco. Splunk Enterprise can run in a private cloud, on premises or in air-gapped environments, which suits regulated industries. You can try Splunk Enterprise free for 60 days with no credit card, and add free prebuilt apps from Splunkbase.
Datadog is the other name that often joins this shortlist, and our Splunk vs Datadog guide sets it against Splunk.
Five questions to decide
- Must the platform run fully offline or air-gapped? Splunk Enterprise supports that.
- Do you want to run it yourself under an open source licence? Elastic's AGPL option allows it.
- Is your network already built on Cisco? Splunk's weighted ingest for Cisco telemetry helps.
- Do you want no servers to manage at all? Elastic Cloud Serverless or Splunk Cloud Platform.
- Will many people need access? Splunk's cloud plans include unlimited users.
Whichever you choose, it works best inside a wider plan, so see my notes on cybersecurity essentials for customer-facing platforms and building a strong security culture.
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My advice on Elastic or Splunk
For a smaller team that's comfortable with open source and wants a choice between running it yourself and a serverless cloud, Elastic is the more flexible start. For larger or regulated organisations, especially those on Cisco networks or needing air-gapped deployments, Splunk is the safer fit. Run both trials against a week of your own logs, because how each handles your data volume will tell you more than any feature list. And don't forget the people side: whoever runs it day to day should help choose it, since they'll live with the queries and dashboards.
Do you make observability or security tools? Tool makers can ask to be considered for a featured place in comparisons like this one.
Frequently asked questions
Is Splunk owned by Cisco?
Splunk describes itself as part of Cisco and says it's supercharged by Cisco.
Is Elastic open source?
Elastic says that in 2024 it added the OSI-approved AGPL as a licence option alongside SSPL and the Elastic License.
Is there a free trial of Splunk?
Yes. Splunk offers Splunk Enterprise free for 60 days with no credit card required.
Can Splunk run on premises?
Yes. Splunk Enterprise can be deployed in a private cloud or on premises, even in air-gapped environments.
What ways can you run Elastic?
Elastic offers Elastic Cloud Serverless, Elastic Cloud Hosted and self-managed Elasticsearch you run locally or on Kubernetes.
