Saiku: Open-Source Semantic Layer for Analytics

Try it in 30 seconds

docker run -d -p 8080:8080 --name saiku -e SAIKU_DEMO=true ghcr.io/spiculedata/saiku

Then open http://localhost:8080/ui/ and log in with admin / admin. Demo mode ships a self-contained H2 + FoodMart cube — drag fields onto rows, columns, or filters and the SPA writes MDX for you.

For a real deployment, drop SAIKU_DEMO=true and set an admin password: -e SAIKU_ADMIN_PASSWORD='a-strong-password'. Saiku refuses to start on the default admin/admin once it's network-reachable, so one of those two is required.

A hosted instance is always live at https://demo.saiku.bi (auto-reset nightly).

What is Saiku

Saiku started in 2010 as an open-source OLAP browser for Mondrian. In 2026 it was rebuilt as a modern Semantic Layer on top of:

• Mondrian 4.8.1.x (Spicule fork) — with a Calcite-based SQL planner alongside the legacy SqlQuery builder. Calcite is the default; force legacy with -Dmondrian.backend=legacy.
• Apache Arrow wire format for cellsets, so the browser and any programmatic consumer share a zero-copy result envelope.
• Jetty 12 EE10 + Jersey 3.1 + Spring 6 + Spring Security 6.5 in a single-JAR Picocli launcher.
• SvelteKit 5 + Vite for the SPA (separate repo, served from inside the same JAR at /ui/).

AI Query API + MCP

Saiku 4.x exposes a typed REST surface — /rest/saiku/api/ai/* — designed for LLM agents. Hierarchies, levels, measures and synonyms are discoverable via /ai/cubes and /ai/schema, and a single POST /ai/query translates a JSON description of a question into validated MDX, runs it, and returns typed {value, formatted, unit} cells. Every validation failure carries a {status, field, available} envelope so an agent can self-correct without scraping logs.

The container also bundles saiku-mcp, a stdio Model Context Protocol wrapper so Claude Desktop / Cursor / Cline can wire to a running Saiku with one line of config:

{
  "command": "docker",
  "args":    ["exec", "-i", "saiku", "saiku-mcp"]
}

See docs/AI-QUERY-API.md and docs/schema-annotations.md for the typed contract and the saiku.semantic.* annotation namespace cubes use to describe themselves to agents.

Dashboards

Build shareable dashboards of chart / table / KPI / text / image tiles over your cubes — with cross-tile filters, click- and brush-cross-filtering, drill-down/through, conditional formatting, combo charts, anomaly/forecast overlays, auto-refresh, PDF/PNG export and read-only share links. See the docs/dashboards-user-guide.md for the full walkthrough, and saiku-ui/src/embed/README.md to embed a dashboard in your own app via the <saiku-embed> web component.

Observability

Saiku ships opt-in OpenTelemetry instrumentation via the OTel Java agent — zero code changes, zero overhead when off. Setting OTEL_EXPORTER_OTLP_ENDPOINT activates auto-instrumentation for Jetty, Jersey, JDBC (every Mondrian-emitted SQL becomes a child span), outbound HTTP, JVM metrics, and DBCP2 connection pool metrics. Trace context is injected into the Saiku log pattern automatically.

docker run -d -p 8080:8080 \
  -e OTEL_EXPORTER_OTLP_ENDPOINT=http://otel-collector:4318 \
  -e OTEL_SERVICE_NAME=saiku-prod \
  ghcr.io/spiculedata/saiku:latest

Without the endpoint env var the agent is never loaded. See docs/observability.md for the full env-var reference, sampling guidance, and what's not yet covered (Tier 2 custom spans for ThinQueryService etc.).

Build from source

JDK 21 + Maven 3.9+ required.

Set up GitHub Packages auth first, or the build fails before it compiles. Saiku's Mondrian fork, olap4j, saiku-query and Ossie artifacts are published to GitHub Packages, which requires an authenticated token even though the packages are public. Without it you get a bare 401 Unauthorized on pentaho:mondrian that never mentions tokens:

1. Create a classic personal access token with only the read:packages scope (Tokens (classic)). It must be classic — GitHub's Maven registry does not accept fine-grained tokens, and the UI defaults to fine-grained. Our packages are public, so no repo scope or org membership is needed.
2. Add five <server> entries to ~/.m2/settings.xml — github-mondrian-saiku, github-olap4j, github-olap4j-xmlaserver, github-saiku-query, github-ossie. Copy the block from .github/workflows/ci.yml; one token covers all five.

Still getting a 401? A fine-grained token and a classic token missing read:packages produce an identical error, so check what the token actually has before minting another — curl -sI -H "Authorization: token $PAT" https://api.github.com/user | grep -i x-oauth-scopes. A classic token's scopes are editable in place, and the value doesn't change, so settings.xml needs no edit.

# Compile, unit tests, Spotless format check (CI gate):
mvn verify

# Build the runnable fat-JAR:
mvn -pl saiku-launcher -am -Dmaven.test.skip=true package

# Run:
java -jar saiku-launcher/target/saiku-*.jar serve --port 8080 --home ./saiku-home

Whole-API integration tests (boots Jetty + the launcher's WAR in-process against the seeded FoodMart H2 datasource):

mvn verify -P integration

See CLAUDE.md for the full layout, the dependency catalog (saiku-bom), and the GitHub Packages auth gotcha for local builds.

Repository layout

saiku-bom/             # central dependency-version catalogue
saiku-core/
  saiku-olap-util/     # olap4j helpers
  saiku-service/       # Semantic Layer service, AI Query, schema gen, async, cache
  saiku-semantic/      # YAML semantic layer
  saiku-web/           # JAX-RS REST resources
saiku-webapp/          # Servlet webapp (Spring XML wiring)
saiku-launcher/        # Picocli CLI + embedded Jetty serving the WAR
saiku-mcp/             # stdio JSON-RPC MCP wrapper
saiku-ui/              # SvelteKit SPA (independent versioning)

The SvelteKit SPA lives in saiku-ui/ and is built independently; the launcher serves the static dist/ under /ui/.

Getting help

• Bugs and feature requests: open an issue.
• Questions, ideas, walkthroughs: GitHub Discussions.
• Chat: Saiku Cloud Slack.
• Stack Overflow tag: saiku.
• Commercial support, hosted, training: [email protected].

The old groups.google.com/a/saiku.meteorite.bi lists and ##saiku IRC channel are no longer monitored.

Contributing

See CONTRIBUTING.md. Short version:

• feature/<name> branch off development — see the Gitflow note in CLAUDE.md.
• Run mvn spotless:apply before committing (a pre-commit hook is available via ./scripts/install-hooks.sh).
• Tests live in **/src/test/java/; integration tests in saiku-launcher/src/test/java/org/saiku/launcher/it/.
• Open the PR against development, not main. main is the release branch — only release/* and hotfix/* PRs go there.

License

Saiku is dual-licensed under Apache 2.0 and EPL 1.0. See LICENSE. A summary lives at https://saiku.bi/#license.

History

The original Saiku project was started by Tom Barber and Paul Stoellberger in 2010 at Meteorite BI and now lives at Spicule. Contributors are listed on the GitHub contributors page.

For release notes see Releases.

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