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EXPRESSLanguage Foundation

International Standards for Information Modelling

501(c)(3)

The language family
behind smart manufacturing

The EXPRESS Language Foundation maintains and promotes the ISO 10303 language family — powering industrial data exchange, interoperability, and digital twins since 1982.

Language introduction Standards & references

5

Languages

40+

Years of history

ISO

10303 Standard

Language Family

Five languages, one standard

Each language serves a distinct purpose in the information modelling lifecycle.

EXPRESS

EXPRESS

The core data modelling language — entities, types, constraints, and rules for defining information schemas.

ISO 10303-11

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EXPRESS-G

EXPRESS-G

Graphical notation for EXPRESS — entity-relationship diagrams for visual data modelling.

ISO 10303-11

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EXPRESS-I

EXPRESS-I

Instance definition language for populated data models and conformance testing.

ISO 10303-12

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EXPRESS-X

EXPRESS-X

Schema mapping language for defining transformations between different EXPRESS data models.

ISO 10303-14

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EXPRESS-Q

EXPRESS-Q

Query language for defining mappings between ARM and MIM schemas with reference path syntax.

ELF Specification

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History

Four decades of innovation

1982

EXPRESS conceived during the PDDI program at McDonnell Aircraft

1986

Proposed as an International Standard at ISO by NBS (now NIST)

1994

ISO 10303-11 published by Schenck & Wenzel; reference manual by Schenck & Wilson

2004

EXPRESS Edition 2 (ISO 10303-11:2004) with Loffredo & Wilson

2022

EXPRESS Language Foundation established as a 501(c)(3) public charity

Heritage

Born from industry leaders

The EXPRESS language originated from collaboration between major aerospace, manufacturing, and standards organizations.

BoeingMcDonnell DouglasGeneral ElectricNISTPDES Inc.STEP ToolsJotne EPM TechnologyAFNeT ServicesRibose

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Latest News

From the foundation

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Aug 17, 2023announcements

Thoughts on EXPRESS

Personal thoughts from inventor of EXPRESS, Douglas Schenck, on the origin and hopes of EXPRESS.

Douglas Schenck

Jun 21, 2022announcements

EXPRESS Language Foundation joins the Metaverse Standards Forum as Principal

The EXPRESS Language Foundation has joined the Metaverse Standards Forum as a Principal and founding member to enable semantic interoperability in the metaverse.

Thomas Thurman

May 1, 2022announcements

A history of the EXPRESS languages

The official account of EXPRESS history, by its founders!

Douglas Schenck, Peter Wilson, Bernd Wenzel

Learning Resources

Get started with EXPRESS

EXPRESS Language Reference Course

The authoritative course on the EXPRESS language from its co-inventor — syntax, semantics, modelling patterns, and practical exercises.

By Peter Wilson, co-author of Information Modelling: The EXPRESS Way

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EXPRESS & STEP in Practice

The applied course on the ISO 10303 ecosystem — STEP file formats, data validation, schema querying, SDAI programming, and PLCS.

Contributed by Jotne EPM Technology

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Join the EXPRESS Language Foundation

We facilitate education, standardization, research, and promotion of the EXPRESS language family. Membership is open to organizations and individuals worldwide.

Founded by the original inventors of EXPRESS, including Douglas Schenck, Peter Wilson, and Allison Barnard Feeney.

ELF is a US-registered 501(c)(3) public charity — your contributions are tax-deductible.

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