Cassini

Statistical Process Control

Control charts, not contracts.

ambient · agentic · audited

A complete SPC platform you deploy on your own infrastructure. Variable, attribute, and short-run charts. Nelson rules, capability analysis, MQTT / Sparkplug B ingestion, time-travel replay, a lakehouse data product, streaming CEP rules, and a 300-endpoint REST API — all in one open-core package. Own your quality data. No vendor lock-in. No per-seat pricing traps.

View Pricing View on GitHub

10+

Chart Types

Nelson Rules

300+

API Endpoints

200K

Samples / Min

SPC Engine

Every chart type. Every rule. No compromises.

Cassini ships a complete SPC engine — not a subset, not a starter kit. If your quality standard references it, Cassini supports it out of the box.

Variable Charts

X-bar & R, X-bar & S, Individuals & Moving Range for continuous measurement data. Plus CUSUM and EWMA for detecting small, sustained shifts that Shewhart charts miss.

Real-time via WebSocket

Attribute Charts

p, np, c, and u charts for defective/defect count data. Includes Laney p' and u' corrections for overdispersed data — the kind most SPC tools silently get wrong.

Overdispersion-corrected

Short-Run Charts

Deviation mode and Z-score standardization for low-volume and high-mix production. Chart multiple part numbers on a single control chart without waiting for 25 subgroups.

High-mix / low-volume ready

Nelson Rules

All 8 Nelson Rules, individually configurable per chart. Pro edition adds preset management with Nelson, AIAG, WECO, and Wheeler rule sets for standardized configuration across your plant.

8 rules, individually configurable

Capability Analysis

Cp, Cpk, Pp, Ppk, and Cpm indices included in Open. Pro edition adds non-normal distribution fitting with Box-Cox transformation and 6 distribution families for data that isn't normally distributed.

Non-normal fitting: Pro

Equipment Hierarchy

ISA-95 compliant structure: Enterprise, Site, Area, Line, Cell, Equipment. Organize charts, data, and permissions the way your plant actually operates — not the way a SaaS vendor decided to model it.

ISA-95 compliant

Cassini SPC dashboard showing an Individuals control chart with Nelson rule violation detection, control limits, and spec limits

Control chart dashboard with real-time violation detection

Cassini data entry screen with manual measurement input, spec limit validation, and batch tracking

Manual data entry with validation

Cassini violations list showing Nelson rule violations with severity, status, and acknowledgement workflow

Violation tracking and acknowledgement

Computation Transparency

“Show Your Work”

Click any calculated value — a control limit, a capability index, a Nelson rule violation — and Cassini shows you exactly how it was computed. Step-by-step. With the formula rendered in KaTeX and citations to the relevant AIAG standard.

No more black-box SPC. When an auditor asks how your Cpk was calculated, you don't open a support ticket. You click the number.

This is the feature quality engineers wish every SPC tool had. Cassini is the one that actually built it.

Cassini Show Your Work panel — clicking the Process Capability Cpk value opens a slide-out with the KaTeX-rendered formula, step-by-step computation, USL/LSL inputs, normality test result, and the AIAG citation

Process Capability — formula + AIAG citation, one click away

Time-Travel SPC Replay

Rewind any chart. Any timestamp.

Pro tier

Cassini reconstructs the exact state of any control chart at any point in its history — control limits, violation state, in-control status, every Nelson rule decision. Built for regulated industries where “what did we see when we made that decision?” is an audit question, not a guess.

Pair it with the hash-chained audit log and Ed25519 electronic signatures and you have a 21 CFR Part 11 compliance story that holds up under deposition. Replay a violation investigation from six months ago. Show an FDA inspector exactly what the operator saw at 03:42 last Tuesday. No reconstruction. No interpretation.

Read the time-travel replay docs →

Cassini time-travel SPC replay — control chart with the ReplayScrubber active showing a historical timestamp, the ReplayBanner overhead, and the chart redrawn with the limits and rule state from that moment

Pick any timestamp. The chart redraws as it was.

Python · Polars · DuckDBread-only

import polars as pl

df = pl.read_parquet(
    "https://factory:8000/lakehouse/samples",
    storage_options={"api_key": "$CASSINI_API_KEY"},
)

df.filter(pl.col("char_name") == "OD-A")
  .group_by_dynamic("ts", every="1h")
  .agg(pl.col("value").mean())

Browser UI for the same API

Cassini Lakehouse

Your SPC data. Your tools.

Pro tier

Cassini Lakehouse exposes your samples, violations, and capability history as a read-only Arrow / Parquet data product. Query it from a Jupyter notebook with Polars, wire it to your Power BI dashboards, or feed it to an ML pipeline. DuckDB-backed analytical layer means interactive queries on millions of measurements without touching the OLTP database.

No CSV exports. No cron jobs copying tables. No analyst asking IT for “just the last six months of OD-A measurements.” Plug your tools straight into the source of truth.

Read the Lakehouse docs →

Streaming CEP Rules

Cross-stream patterns. Sliding windows.

Enterprise tier

Standard SPC catches violations on a single characteristic. Real failure modes correlate across characteristics, lines, and time. Streaming CEP rules let you express those patterns in YAML — combine Nelson rules across multiple streams within a sliding time window, hot-reload the engine, and edit rules live in the embedded Monaco editor with full schema validation.

“If OD-A trends out-of-control AND coolant temperature drifts more than 2σ within the same 15-minute window, page the line lead.” That's one rule. Hot-reloaded. Audited. No restart.

Read the Streaming CEP docs →

Cassini Streaming CEP Rules editor — Monaco YAML editor with syntax-highlighted multi-stream pattern (window, conditions, action) and inline validation

Author rules in YAML, hot-reloaded into the live engine

Measurement System Analysis

Trust the gauge before you trust the data.

Pro tier

Crossed ANOVA, range method, nested ANOVA, and attribute agreement analysis (Cohen's and Fleiss' Kappa). AIAG MSA 4th Edition d2* tables. The full study lifecycle — setup, data collection, analysis, interpretation — with the same Show Your Work transparency you get on the control charts.

Variance components decomposition with the four AIAG buckets (Repeatability, Reproducibility, Gage R&R, Part Variation), %Study Variation, %Tolerance, and number of distinct categories — colour-coded against AIAG acceptance thresholds so you see “Marginal” before you sign off on a part.

Cassini MSA Gage R&R study results — Bore Diameter Gage R&R, Crossed ANOVA, %Study GRR = 13.3% (Marginal), ndc = 10, variance components bar chart showing Repeatability, Reproducibility, Gage R&R, Part Variation, with full source table

Bore Diameter Gage R&R — variance components, %GRR, ndc

Data Integration

Connect any data source.

From manual calipers to fully automated production lines, Cassini ingests data however it arrives.

MQTT / Sparkplug B

Subscribe to industrial IoT brokers and ingest measurement data in real time. Native Sparkplug B payload decoding for direct PLC integration. Open includes one broker; Pro unlocks unlimited.

OPC-UAPRO

OPC-UA server management. Browse nodes, configure subscriptions, and map tags to SPC characteristics — all from the browser. Available with Pro license.

Gage BridgeENTERPRISE

RS-232 and USB serial connections to handheld gages, micrometers, and CMMs. Press the button on the gage, see it on the chart.

CSV / Excel Import

Guided import wizard with column mapping, validation rules, and preview. Migrate historical data or import batch records without writing code.

REST API

300+ endpoints covering every entity in the system. Build custom integrations, automate data collection, or feed Cassini from your MES, ERP, or LIMS.

Manual Entry

Touch-friendly data entry with input validation, spec limit enforcement, and operator prompts. Built for the factory floor, not the back office.

Cassini Connectivity Hub showing MQTT broker status, data flow pipeline from sources through ingestion to SPC engine, and server monitoring

Connectivity Hub with data flow pipeline monitoring

Infrastructure

Deploy anywhere. Your servers, your rules.

Cassini runs where your data lives — on-premise, in a private cloud, or on a Raspberry Pi bolted to a machine. No phone-home. No cloud dependency.

Docker

Single-command deployment. Production-ready container images with health checks and volume persistence.

Multi-Database

SQLite for single-site. PostgreSQL, MySQL, or MSSQL for enterprise scale. Swap with a config change.

PWA + Offline

Install as a native app on any device. Full offline support for areas with unreliable connectivity.

Kiosk + Dashboard

Kiosk mode for factory floor terminals. Wall dashboard mode for control room displays. No mouse required.

Cassini kiosk mode showing a full-screen control chart with large navigation arrows, control limits, and real-time violation indicators

Kiosk mode — touch-friendly, full-screen SPC for the factory floor

Editions

Open · Pro · Enterprise

Open Edition is a full SPC platform — not a crippled demo. Pro adds production databases, multi-plant, and quality tooling. Enterprise adds compliance, advanced analytics, and dedicated support.