What CLEARSY does

CLEARSY is a French engineering SME founded January 1, 2001 by the team that industrialized the Atelier B formal modeling tool. The company specializes in safety-critical software and systems engineering certified to SIL1 through SIL4 levels, serving clients in railway and transit (RATP, SNCF Réseau, New York City Transit, São Paulo Metro, Luxtram, Cross River Rail, Macao Light Metro, Kuala Lumpur Metro, Honolulu Metro), nuclear energy (EDF, CEA, Framatome, SCK-CEN, ITER, Hexana), defense (EXAIL, DGA), automotive, aerospace, and microelectronics sectors.

The company's product portfolio spans certified development tools, hardware platforms, and turnkey safety systems. Core technology assets include the Atelier B formal-methods IDE (over 10,000 downloads, T2 certified in 2024), the CLEARSY Safety Platform (SIL4-certified industrial computing platform with a 3,000 EUR HT starter kit), the RS4 range of SIL4 safety relays and latching interfaces, the Baseline 3 ETCS DMI display (SIL2, ERA opinion-lettered, 45,000+ units sold since 1997), and platform screen door control systems COPPILOT and DOF. Supporting tooling includes CLEARSY Data Solver (T2 certified 2025), Data Manager, Data Generator, TestRunner, DAME, and ERTMS/ETCS operational and traffic simulators. Recent product launches—LCHIP (2023), Atelier B T2 Certified Edition (2024), Data Solver new version (2025), and the 3U CLEARSY Safety Controller—indicate an accelerating productization cadence.

CLEARSY operates three revenue streams: safety systems development and integration services (professional services), safety components and tools sales (hardware and licensed software), and Qualiopi-certified training programs. The company sells exclusively through direct enterprise engagement, with four French offices (Aix-en-Provence headquarters, Paris, Lyon, Strasbourg), an established US presence (2026), and project-based delivery across Europe, Asia-Pacific, and the Americas. Pricing is not publicly disclosed beyond the Safety Platform Starter Kit; large enterprise engagements require direct quotation. The company holds an extensive certification portfolio (EN 50126/50129/50155, IEC 61508, Common Criteria, NFPA 130, T2 certifications) and maintains strategic partnerships with Siemens Mobility, Alstom, Hitachi Rail, Stadler, Hyundai Rotem, CAF, CRRC, UIC, ERA, and DGA.

Name

CLEARSY

Legal name

SAS CLEARSY

Website

https://clearsy.com

Company type

Private

Founded year

2001

Operating status

Operating

Headcount range

51–100 employees

Short description

CLEARSY is a French SME founded in 2001 that engineers SIL1-SIL4 certified safety-critical software and hardware systems using formal methods (B Method, Atelier B) for railway, nuclear, defense, automotive, aerospace, and microelectronics clients globally.

Ownership category

akta.pro rank

Product category

Safety-Critical Systems Engineering

NAICS

Navigational, Measuring, Electromedical, and Control Instruments Manufacturing (33451), Instrument Manufacturing for Measuring and Testing Electricity and Electrical Signals (334515), Electronic and Precision Equipment Repair and Maintenance (8112)

SIC

Measuring & Controlling Devices, Nec (3829), Industrial Instruments For Measurement, Display, And Control (3823), Railroad Equipment (3743), Instruments For Meas & Testing Of Electricity & Elec Signals (3825), Services-Testing Laboratories (8734)

akta.pro primary industry

Safety Instrumented Systems & Machine Safety Control (SIS, Safety PLCs, Relays) (IMAGABAF)

akta.pro secondary industries

Rolling Stock Testing, Inspection & Certification (NDT, commissioning, compliance) (TLAKAIAM), Third-Party Certification, Code Compliance & Regulatory Inspection (ASME/API/ISO) (EUAEAHAN), Automotive & Safety-Certified Processors (ADAS/Domain/ASIL MCUs) (HDAHAJAJ), Electrical Testing & Certification (Protection Relays, Switchgear, Transformers) (EUAEAHAG)

Keywords

• Formal methods software
• Safety-critical systems
• Railway signaling solutions
• SIL4 certified hardware
• Nuclear safety engineering

Headquarters

HQ city

Aix-en-provence

HQ country

France

HQ region

Europe

Offices4 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Technology or R&D, Operations, Marketing or Sales, Infrastructure

Revenue model

1. Safety Systems Development & Integration: Custom development of safety-critical software and systems for clients in railway, nuclear, automotive, defense, and aerospace sectors. Projects range from software development to turnkey system delivery with formal verification and certification to SIL1-SIL4 standards.
2. Safety Components & Tools: Sale of safety-certified components including RS4 safety relays, CLEARSY Safety Controller, CLEARSY Safety Platform, and ETCS DMI displays. Also includes development tools like Atelier B.
3. Training & Certification Services: B Method training programs and certification support services. Company is a Qualiopi-certified training center.

Pricing tiers

Go-to-market motion1 record

Distribution channels3 records

Marketing channels5 records

Core offering

CLEARSY designs, develops, and certifies safety-critical software and systems at SIL1 to SIL4 levels using formal methods (B Method and Atelier B). The company delivers turnkey safety systems, safety-certified hardware components (RS4 relays, CLEARSY Safety Platform, ETCS DMI), formal development tools, and engineering services to the railway, nuclear, automotive, defense, aerospace, and microelectronics industries.

Product overview

CLEARSY is a French SME specialized in safety-critical software and systems engineering, offering a comprehensive portfolio of products and services for safety levels SIL1 to SIL4. The product portfolio includes: Atelier B development environment for formal methods-based software development; CLEARSY Safety Platform (SIL4-certified industrial computer and controller); RS4 safety relays and latching interface systems; Baseline 3 ETCS DMI displays; and various safety systems including COPPILOT/DOF platform door controls, KFS automatic train stops, KPVA overspeed controls, DIL gap detection, and supervision systems. CLEARSY also provides ERTMS/ETCS simulation tools, data validation tools (Data Solver, Data Manager, Data Generator), test automation (TestRunner), and maintenance tools (DAME). The company serves railway, nuclear, automotive, defense, aerospace, and microelectronics sectors.

Differentiator

Problem solved

Functional benefit

Brands

• Atelier B: Integrated development environment (IDE) for formal methods B and Event-B, used for developing safety-critical software
• CLEARSY Safety Platform
• RS4 Safety Relay
• COPPILOT
• CLEARSY Data Solver
• DOF

Products and services

• Atelier B Integrated development environment (IDE) for B and Event-B formal methods used to develop safety-critical software with mathematical proof-based verification; T2 certified per EN50129 for SIL4 applications, with over 10,000 downloads.
• CLEARSY Safety Platform SIL4-certified industrial computer and development platform for building safety-critical control systems, available as a starter kit for industry and academic use.
• RS4 Safety Relays SIL4-certified safety relays (DIN format variants RS4.DIN.202, RS4.DIN.304, RS4.DIN.402, RS4.DIN.406, RS4.3U) featuring normally open and normally closed contacts with weld no transfer compliance per EN 61810-3 Type A for railway signaling applications.
• RS4.B Latching Interface System SIL4-certified latching relay system for railway wayside applications enabling DAY/NIGHT switch functions, route latching, and switch machine safety latching with modular contact configurations up to 200 contacts.
• CLEARSY Safety Controller Pre-packaged 3U rack SIL4 controller for industrial safety applications.
• Baseline 3 ETCS DMI 10.4-inch HMI platform providing SIL2 display, interaction and computation for ETCS Baseline 3 trains, with over 45,000 units sold since 1997.
• CLEARSY Data Solver T2-certified tool for formal validation of railway signaling parameter data, accelerating data validation processes for SIL4 applications.
• CLEARSY Data Manager Tool for managing large quantities of railway signaling data representing tracks and associated objects.
• CLEARSY Data Generator Tool for generating theoretical track equipment positioning data for new projects or line renovations.
• COPPILOT SIL3-SIL4 certified automatic platform screen door control system for metro applications.
• DOF (Door Opening/Fermeture) SIL3-SIL4 certified automatic platform screen door control system for metro platforms, certified SIL3 for Cross River Rail in Australia.
• KFS SIL2 Automatic Train Stop System SIL2-certified automatic train stop system (Dispositif d'arrêt automatique des trains) for tramways and trains, including custom versions for work trains on the Paris network.
• KPVA Overspeed Control System Train overspeed control system (Contrôle Ponctuel de Vitesse Autonome) with approximately 300 beacons in service on Paris metro lines.
• ERTMS/ETCS Simulators Range of ERTMS/ETCS simulators including operational simulators, traffic simulators, OBU test benches, and RBC/IXL test benches.
• DIL Gap Detection System SIL3-certified system (Détection d'Individus dans les Lacunes) for detecting individuals in platform gaps to prevent falls.
• Fall Protection Device (Gap Filler) Passive anti-fall device with aluminum comb-like teeth that fills the gap between platform and train, approved by RATP.
• Supervision Gateway SIL2-certified supervision gateway for fire safety and ventilation systems, deployed on Grand Paris Express.
• TestRunner Automated test realization platform for testing safety-critical systems.
• DAME Maintenance and Exploitation Aid Device High-performance data/events logger and analyzer middleware (Dispositif d'Aide à la Maintenance et à l'Exploitation) for industrial systems.
• SATURN Remote Safety I/O SIL2-SIL4 certified remote safe input/output modules (Entrées/Sorties Sécuritaires Déportées) for distributed safety applications.
• Network of Safe Data Communication Modules SIL4-rated network modules enabling safe data communication inputs along tracks to eliminate expensive cables.
• B Method Training and Certification Services Qualiopi-certified professional training programs on B Method delivered directly to enterprise clients at CLEARSY premises or client sites.
• Custom Safety-Critical System Development and Integration Custom development of safety-critical software and systems for clients in railway, nuclear, automotive, defense, and aerospace sectors, ranging from software development to turnkey system delivery with formal verification and certification to SIL1-SIL4 standards.

Quantifiable outcome

• Atelier B tool surpassed 10,000 downloads
• +3 more outcomes

Named customers23 records

Segments6 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration1 record

Feature8 records

Partnerships

22 partnerships are on record, tiered core and minor.

• ERSAcoreStrategic or Co-development PartnerERSA joined CLEARSY in a significant step for the company. ERSA provides simulators and training solutions that complement CLEARSY's safety-critical systems portfolio.
• Hitachi RailcoreTechnology or IntegrationCLEARSY provides SIL4 safety networks and platform screen door control systems to Hitachi Rail for metro projects including Honolulu. Partnership includes simulator development agreements.
• Siemens MobilitycoreTechnology or IntegrationLong-standing partnership for signaling projects. CLEARSY secures Siemens supervision software and provides displays for RER trains. Siemens renewed CLEARSY's supplier referencing.
• Alstom TransportcoreTechnology or IntegrationStrategic partners in railway innovation. CLEARSY develops safety-critical components integrated into Alstom rolling stock and signaling systems.
• EXAILcoreStrategic or Co-development PartnerSince 2022, CLEARSY has been supporting EXAIL in producing new equipment for a sea demining system, representing a long-term collaboration in defense innovation.
• StadlercoreTechnology or IntegrationStadler provides work trains to RATP requiring compatibility with Paris network signaling. CLEARSY delivers custom automatic train stopping systems.
• CENTRALPcoreStrategic or Co-development PartnerJoint development partnership with CENTRALP for ETCS DMI (Display Machine Interface) consoles, combining CLEARSY's safety platform with CENTRALP's display expertise.
• HYUNDAI ROTEMcoreTechnology or IntegrationPartnership for train control systems in South East Queensland network, combining CLEARSY's safety systems with Hyundai Rotem's rolling stock.
• UIC (International Union of Railways)coreStrategic or Co-development PartnerCLEARSY is a partner of UIC to define methods for demonstrating safety of innovative systems, contributing to global railway safety standards.
• ERA (European Union Agency for Railways)coreStrategic or Co-development PartnerCollaboration with ERA on ERTMS simulation for tomorrow's railway. ERA is studying the evolution of ERTMS standards with CLEARSY's support.
• DGA (Délégation Générale de l'Armement)coreStrategic or Co-development PartnerCLEARSY leads the OISAU study for DGA defining architecture standards for future autonomous military systems using formal methods.
• LORIA (Université Henri Poincaré Nancy II)minorStrategic or Co-development PartnerAcademic partner in RIMEL project for incremental event-based model refinement, coordinated by LORIA.
• LABRI (Université Bordeaux I)minorStrategic or Co-development PartnerAcademic partner in RIMEL research project on formal methods refinement.
• STMicroelectronicsminorStrategic or Co-development PartnerPartner in FORCOMENT project demonstrating that Event-B models can be transformed into hardware descriptions for microcontrollers.
• SAGEMminorStrategic or Co-development PartnerLeader of CERCLES research project on compositional certification of embedded critical software, with CLEARSY as partner.
• ThalesminorStrategic or Co-development PartnerPartner in MegaMart H2020 project on scalable model-based framework for complex systems development and validation.
• BombardierminorStrategic or Co-development PartnerPartner in MegaMart H2020 project alongside CLEARSY and other European companies.
• VolvominorStrategic or Co-development PartnerPartner in MegaMart H2020 project on model-based systems engineering.
• NokiaminorStrategic or Co-development PartnerPartner in MegaMart H2020 project on model-based framework.
• AtosminorStrategic or Co-development PartnerPartner in MegaMart H2020 project alongside CLEARSY.
• ENSIIE (École Nationale Supérieure d'Informatique pour l'Industrie et l'Entreprise)minorStrategic or Co-development PartnerENSIIE engineering school partnership for training and student placement programs.
• IMD/UFRN (Institut Métropole Digital, Brazil)minorStrategic or Co-development PartnerInternational partnership with Brazilian university for training, hackathons, and Master's level courses on CLEARSY Safety Platform.

Scale indicators6 records

Recent moves7 records

Expansion highlights5 records

Direct peers

• LDRA: UK-based tool vendor for safety-critical software verification (MISRA, DO-178C, IEC 61508, ISO 26262). Overlaps with CLEARSY's TestRunner and Atelier B offerings as a software-verification toolchain for regulated industries.
• Systerel: French engineering firm specializing in formal methods (Atelier B / Event-B) and safety-critical systems for railway, nuclear and aerospace — the closest direct competitor to CLEARSY with overlapping tooling and certifications.
• SQS (Sogeti / Capgemini Engineering): Former SQS software quality and formal-methods unit (now within Capgemini Engineering) historically competed with CLEARSY in B-Method-based safety software certification for rail and aerospace programs.

Broad incumbents

• Hitachi Rail: Major signaling and rolling-stock supplier (CBTC, ETCS, ERTMS) that procures CLEARSY SIL4 networks and platform screen door systems, while also fielding its own end-to-end signaling offerings.
• Thales: Tier-1 safety-critical electronics and signaling provider for rail (Thales Transportation) and aerospace/defense. MegaMart H2020 partner with CLEARSY, but competes in adjacent safety-critical platforms.
• Vector Informatik: German embedded-software tools and AUTOSAR solutions vendor with strong automotive functional-safety (ISO 26262) footprint. Comparable as a safety-critical development toolchain provider, particularly for CLEARSY's automotive vertical.
• ETAS (Bosch): Bosch subsidiary providing tools, middleware and services for automotive software development (AUTOSAR, functional safety, security). Comparable as a vertically-specialized safety-critical toolchain vendor in the automotive safety segment.
• Alstom: World-leading rolling stock and signaling OEM with digital mobility, ERTMS and train control portfolios. Strategic partner of CLEARSY; competes indirectly by integrating signaling stacks at the system level.
• TTTech: Austrian safety-computing platform vendor for automotive, aerospace, off-highway and industrial automation (TTEthernet, MotionWise). Comparable as a SIL-grade deterministic safety platform provider targeting multiple verticals.
• Siemens Mobility: Global rail signaling and rolling-stock incumbent (CBTC, ETCS, axle counters) and a long-standing CLEARSY customer/partner. Overlaps with CLEARSY on signaling safety systems but at much greater scale and scope.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks6 records

Key highlights7 records

Customer concentration

• Xx.com/ClearsyContact

Compliance13 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about CLEARSY