Editorial · Self-hosted alternatives

Open Source RUM 2026

Three viable open-source RUM options exist in 2026. None is operationally free, the SDK is free, the backend infrastructure and operations are not. Here's the realistic economics.

Direct answer

What are the open-source RUM options in 2026?

Grafana Faro (Apache 2.0 SDK + Grafana Stack backend), Boomerang.js (SOASTA legacy library, still maintained), and Sentry self-hosted (full Sentry SaaS deployed on your own infrastructure). All have zero SaaS cost but real infrastructure and operations cost, typical all-in $30K-$100K/year for a production deployment.

Grafana Faro

The newest entrant and probably the strongest. Faro is the open-source RUM SDK from Grafana Labs, paired with the Grafana Alloy collector. Telemetry forwards into Loki (logs), Mimir (metrics), and Tempo (traces). Visualization is in Grafana. Apache 2.0 throughout.

SDK: free, open-source.
Backend: self-hosted Grafana Stack (free under AGPL) or Grafana Cloud (per-GB ingest).
Best fit: teams already running Grafana for backend observability.
Operational cost: $30K-$60K/yr for self-hosted production deployment.

See Grafana Faro pricing for the full breakdown.

Boomerang.js

Boomerang is the original open-source RUM library, originally developed by SOASTA (acquired by Akamai 2017 and now powering Akamai mPulse internally). The library is still maintained as open-source and is genuinely powerful, Akamai uses it in production for mPulse, which is one of the most mature commercial RUM products.

SDK: free, BSD licence.
Backend: you write your own. Beacon endpoint receives the data; you process and store it.
Best fit: teams who want the proven Boomerang capture model but want to own the data pipeline end-to-end.
Operational cost: highest of the three, you build the backend yourself. $50K-$150K/yr in engineering for a production deployment.

Sentry Self-Hosted

Sentry publishes its full SaaS stack as self-hosted Docker images. You can run the entire Sentry product on your own infrastructure, errors, performance, session replay, alerting, the lot. Sentry licences the core under BSL (Business Source License) with the source available; restrictions on offering Sentry as a competing SaaS to your own customers, but unlimited for internal use.

SDK: same SDK as SaaS Sentry, free.
Backend: full Sentry stack (Django + Snuba/ClickHouse + Kafka + Redis) on your own infrastructure.
Best fit: teams who like the Sentry product but need on-prem deployment for compliance or data-residency reasons.
Operational cost: $40K-$100K/yr including database operations and Kafka management.

What none of these include

The vendor support layer. SaaS Sentry has support; self-hosted Sentry has GitHub issues.
Multi-tenant billing and ownership. All three assume single-organisation use.
Automatic SDK upgrades. You install SDK upgrades on your own schedule.
Automatic infrastructure scaling. You size and scale the cluster.
Cross-product integrations (PagerDuty, Slack, GitHub). Most require manual webhook configuration.

When self-hosted makes sense

Data residency or compliance requires the data path stays under your control.
You already have the operations capacity for Grafana Stack, ClickHouse, or Kafka clusters.
Your scale ($300K+/yr commercial bill equivalent) makes self-hosting economically attractive.
You have specific customisation needs the vendor SaaS won't accommodate.

When self-hosted is the wrong choice

You want managed-SaaS simplicity.
You don't have dedicated operations engineering for the backend.
Your scale ($30K-$100K/yr commercial equivalent) is below self-hosting break-even.
You need vendor support for critical-path RUM availability.

For commercial alternatives at small scale, see RUM for small business — Cloudflare free is operationally simpler than any self-hosted option.

Last verified June 2026