IEC 61025 · ISO 26262 · ARP4761

Fault tree analysis that meets the standards you're audited against.

A professional-grade FTA workspace that runs entirely in your browser. Built for safety engineers, reliability teams, and compliance-driven industries that can't afford five-figure desktop licences — or limitations.

Launch Studio — Free → Talk to us about Enterprise
No account. No credit card. Runs in your browser.
Simple fault tree diagram TOP EVENT System failure AND BE-01 Sensor fail BE-02 Relay stuck
Capabilities

Everything you need for IEC 61025 analysis.

From deterministic minimal cut sets to uncertainty-aware Monte Carlo — the full analytical stack, not a stripped-down subset.

Analysis engine

MOCUS minimal cut sets

Deterministic minimal cut set generation with no simulation variance. Handles AND, OR, Voting, Inhibit, PAND, and XOR gates under IEC 61025 semantics. Non-coherent gates (NAND, NOR, NOT) require BDD analysis and are on the roadmap.

Importance measures

Birnbaum, Fussell-Vesely, RAW, RRW

Quantify which basic events drive top-event probability. All four standard measures computed per event, sortable, exportable.

Uncertainty

Monte Carlo simulation

xoshiro128** PRNG, chunked async execution that won't freeze your tab, live convergence plots, and sensitivity analysis on every basic event.

Interchange

IEC 61025-compliant exports

SVG, PDF, RTF, PNG, JPEG, and portable JSON for round-tripping between tools. Exact geometry constants, not pixel estimates.

Multi-page

Transfer gates across diagram pages

Handle trees that don't fit on one sheet without losing coordinates. Per-page position isolation means subtree layouts survive every render cycle.

Probability models

Exponential, Weibull, constant, λ×FH

Pick the probability model that matches your data, per basic event. Use constant failure rates, exponential with mission time, Weibull with shape/scale, or λ×flight-hours.

Examples

Start from a working template.

Eight industry-grade fault trees with calibrated probability data. Open one in a click — no setup, no signup.

Aviation · ARP4761 DAL-A

Total Loss of Aircraft Hydraulic Power

Triple-redundant systems A/B + RAT backup. 13 nodes · 25,000 hr mission.

Open in Studio → Automotive · ISO 26262 ASIL-B

AEB System Fails to Activate

Sensors, ADAS processing, actuation, and redundant power paths. 16 nodes.

Open in Studio → Rail · EN 50126 SIL 4

Signal Passed at Danger (SPAD)

Signalling failure, ATP failure, and driver-error pathway. 15 nodes.

Open in Studio →
See all 8 templates →
Written against
IEC 61025:2006 IEC 61508 ISO 26262 ARP4761 EN 50126 MIL-STD-882E
Positioning

Between heavyweight and toy.

Legacy desktop suites cost a fortune and lock you into Windows. Open-source tools stop short of the analysis rigour regulators expect. FTA Studio sits precisely in the gap.

Legacy desktop

ReliaSoft, Isograph, Siemens

The incumbents.

  • Five-figure annual licences
  • Windows desktop only
  • Heavyweight install and IT overhead
  • Vendor lock-in on file formats
The middle path

FTA Studio

Professional tool, modern delivery.

  • Free Community tier, forever
  • Runs in any modern browser
  • IEC 61025 JSON interchange
  • $99 / seat / year Enterprise
Open source

Scram, OpenFTA, others

The free alternatives.

  • Limited analysis coverage
  • Sparse importance-measure support
  • Thin documentation
  • DIY compliance story
Privacy by architecture

Your fault tree data never leaves your device.

For ITAR-controlled programs, CUI-sensitive work, and any organisation that treats reliability data as confidential IP — Community edition is a closed system. Nothing phones home. Nothing is collected. Nothing is stored off-device.

Read the full privacy policy →
  • Browser-only Community edition. No server, no telemetry, no phone-home.
  • localStorage is the only persistence. Clear your cache and the data is gone.
  • No tracking cookies. No analytics pixels. No third-party scripts.
  • Enterprise activation sends only a licence key and per-seat fingerprint.
FAQ

Questions, answered.

The quick version. For anything else, email support@ftastudio.app.

Is Community really free?
Yes. Full IEC 61025 analysis, MOCUS minimal cut sets, importance measures, every export format, and multi-page diagrams. Forever. No trial, no expiry.
What does Enterprise add?
FMEA with RPN, Event Tree Analysis, Monte Carlo simulation, analytics dashboard, audit-ready compliance reports, and priority support. See the pricing page for the full comparison.
Does my data leave my device?
No. Community is 100% browser-side. Enterprise sends only a licence key and per-seat fingerprint to api.ftastudio.app at activation. Project data never leaves your machine.
Does this comply with IEC 61025?
FTA Studio implements IEC 61025:2006 symbols and geometry exactly, with JSON interchange. Compliance of your analysis is your responsibility; the tool gives you the vocabulary to produce compliant outputs.
Which browsers are supported?
Current Chrome, Edge, Firefox, and Safari. No Internet Explorer. Not recommended on mobile browsers — the UI needs a real screen for production work.
Can I use it offline?
Yes, once loaded. Community needs no network after the first page load. Enterprise needs a brief connection at licence activation and at periodic re-check intervals.
Can I self-host?
Enterprise customers in regulated environments: yes — talk to us. Air-gapped deployment with customer-held keys is on the roadmap.
How do I get support?
Email support@ftastudio.app. Enterprise customers get priority response.

Start in 10 seconds. Or talk to us first.

Community is free. Enterprise is a conversation.

Launch Studio — Free → Talk to us about Enterprise
$0 Community · $99/seat/year Enterprise · No credit card