What are my responsibilities after publishing using Simplex?
User Support
The organisation publishing a SNOMED CT Edition using Simplex must offer the first line support for the release that they publish. The organisation name and a contact email must be provided during the release process to be included in the release package readme file.
The support effort can be minimized using pre-written responses and signposting to existing relevant support resources. You should expect there to be general questions about how SNOMED CT should be used in the relevant country or region and perhaps some technical questions.
The simplest way to respond to these questions is to direct people to a web page. A page should be created to provide any country or region-specific information. For more general questions people can be referred to the SNOMED CT Document Library, which includes the starter guide and RF2 specification.
For very specific questions the publishing organisation can contact the International Implementation Support Team for assistance implementation@snomed.org.
Content Updates
A SNOMED CT Edition published from Simplex contains both your created extension content and the International Edition. A new version of the SNOMED CT Edition should be published at least once a year including an up-to-date version of the International Edition. This ensures that downstream users can benefit from the latest developments in the International Edition, even if your extension content has not changed.
In addition to the above, it is good practice to provide a feedback mechanism, or a method for users to propose changes or additions to the content. This could be as simple as providing an email address for feedback or utilizing more dedicated request submission services. Establishing a clear and accessible process for feedback helps ensure the content remains relevant and meets user needs.
By following these steps, you can seamlessly create subsets into your SNOMED CT extension using Simplex. Follow the steps below to set up the subset. Please note that the steps below will create the concept identifying and naming your subset, i.e. a concept of the type 'simple type reference set'.
1. Click "Artifacts"
Access the Artifacts section.
2. Click "New Artifact"
Initiate the creation of a new artifact.
3. Click here
Click here
4. Click "Subset"
Select the subset option.
5. Click "Preferred term"
Choose the Preferred term option.
Select Preferred term once more.
Enter the name of the subset. This term will be the preferred term for the concept identifying your subset.
Finalize and create the subset.
You have now created the concept used to identify and name the subset, but members have yet to be added.
First, navigate to the extension artifacts manager area in Simplex.
2. Click "Simple extension concepts"
Here, you'll notice that some concepts have already been added. These include the metadata concepts required to represent the extension plus any derivatives you have added. To view the concepts, and the details for managing these, click "Simple extension concepts".
3. View concepts
Now, you see the concepts currently included in your extension to the right of the screen. Notice how you see the concepts naming and identifying the derivatives you have created. You will also find your module concept.
4. Click "Download"
To create a new concept for your extension, the first thing you need to do is to download the spreadsheet with the details about the concepts in your extension. Click the download button to the right of step 1 in the process description below the concepts.
5. Access browser
Before editing the spreadsheet you just downloaded, you need to make sure that you know the details of the parent concept of your new extension concept. Therefore, go to your extension browser. You can do this by following the link next to any of your extension concepts
In the browser, do a search for the concept that should be the parent of your extension concept. In this example, I want to create a concept representing a local procedure on the respiratory system. So, the parent I want is the concept procedure on respiratory system.
Once you've identified the appropriate parent concept for your new extension concept, copy the conceptId and a term for the parent concept.
Now, open the spreadsheet with the extension concepts you downloaded earlier in your preferred spreadsheet editor. Bear in mind that you should be able to save the spreadsheet in Excel format after editing.
This is the spreadsheet in which you apply all the information required to create your extension concepts. The first row includes some instructions helping you to add the necessary information correctly. Notice how the first two columns include the concept identifier and the terms for the parent concepts.
In the first column, enter the conceptId for the parent concept, and in the second column, add the term for the parent concept. Notice that each extension concept created in Simplex can only have one parent.
As you are creating a new concept for your extension, you should ignore columns C and D, which are used to hold the identifier for the concept and the active state. When uploading the spreadsheet into Simplex, it will generate an identifier for your concept and assign it the status of active.
Having provided the details about the parent concept, navigate to column E and F to apply the terms for the new extension concept. Column E is for terms in English and the US-English dialect. Column F is for terms in your local language or dialect.
In this example, I am only going to create terms in English. In the same row as the details for the parent concept, I enter the term that is going to be the preferred term
In the subsequent rows, you can add the synonyms you want for your concept. Please note that you don't need to add any values in column A to D
Once you have created your concepts and the related terms, you should save and download the spreadsheet in Excel format.
Once you have edited the spreadsheet with the details of your extension concepts, navigate back to simplex.
Click the 'choose file' button in step 3 of the process and once the file has been selected, you click the 'upload data' button.
Once the import has been performed, you can now see the concept in the list of extension concepts. In the case of multiple concepts, you may have to navigate to another page, to see them all.
You can click 'Open in Browser', to view the concept and its associated synonyms.
In the browser, you can now see the concept appearing in the hierarchy as expected, with the parent you stated in the spreadsheet. You can also see the terms you stated as synonyms. Note that the concept has inherited the defining properties from its parent. In this example, the concept has a procedure site of 'Structure of respiratory system'
Note: Simplex does not support the creation of SNOMED CT subsets. Subsets should be created in a dedicated tool, such as the Reference Set and Translation Tool.
Step 1: Prepare Your Input File Simplex accepts input files in two formats: Excel files or export files from the Reference Set and Translation Tool.
By following these steps, you can seamlessly integrate subsets into your SNOMED CT extension using Simplex. Should you have any questions or encounter any issues, please refer to our documentation or reach out to our support team for assistance.
\
Steps
References
Manage Releases in Simplex
Simplex Release Cycle Overview
The Simplex release cycle is organized into three sequential stages that guide an extension from active editing through to publication, see the diagram below.
Editing
This is the active development phase.
Key activities include:
Dependency configuration (linking to a parent or international edition and updating dependency versions).
Content development, where content managers upload and modify extension content.
Validation, where automated checks are run to identify issues (with the ability to rerun validation if errors occur).
Any system or validation errors must be resolved before moving forward.
Preparing Release
This stage begins once editing is complete.
It focuses on:
Release Ready for Publication
The final stage before completion.
Includes a technical review to confirm the extension meets publication requirements.
Open your extension in Simplex.
From the left-hand menu, select Manage Edition.
The Manage Edition page displays the current release cycle, showing progress from editing through to publication and providing access to validation, review, and release actions.
Review, allowing users to inspect changes via a daily build and download reports (e.g., XLS).
Release validation, ensuring the content is technically and semantically sound.
Final content review, confirming that all changes are correct and approved.
The release cannot proceed until these checks are completed and content changes are approved.
Once ready, the extension can be published, completing the release cycle.
In Simplex, the Editing cycle represents the phase in which extension content is created and prepared for release. While Simplex manages the overall lifecycle of an extension, the actual content development and editing activities take place outside of Simplex, using SNOMED International’s open authoring tools.
The Editing cycle brings together content produced by contributors and prepares it for validation and release through Simplex.
Content Development Outside Simplex
Simplex does not function as a primary authoring tool. Instead, it acts as an integration and release management platform that consumes content developed in external systems.
During the Editing cycle, content may be created and maintained using the following tools:
Snap2SNOMED
Used for creating and maintaining maps. Please see
Refset and Translation Tool
Used for creating SNOMED CT subsets, including simple reference sets within the extension. Please see
SNOMED CT Translation Tool
Used for creating and maintaining translations of SNOMED CT content. Please see
Spreadsheets
Used for creating new concepts, including simple modelled concepts required for the extension. Please see
These activities are typically carried out by extension contributors including subject matter experts (clinical and terminological), and members of the National Release Center.
The purpose of the Editing cycle in Simplex is to bring externally created content together so that it can be validated and prepared for release.
At the end of the Editing cycle:
Content must be in a format suitable for import into Simplex
All required content types must be complete
Dependencies must be correctly configured. This means that the content of the various derivatives and extension content should depend on the version of International Edition specified as the dependency for this release, please see )
Once content has been successfully integrated and validated, the Editing cycle is considered complete and the extension can progress to release preparation.
Features
Simplex provides a streamlined set of tools to help Members and Affiliates create and manage SNOMED CT extensions. Its features are focused on keeping the process simple, affordable, and standards-compliant, while still giving you the flexibility to tailor content to your local needs.
Extension Management
Organize content into modules for maintenance and publication.
Add and update subsets, translations, maps, and concepts all in one place.
Manage your extension lifecycle from setup to release.
Set up translation sets
Import existing translations into Simplex.
Publish SNOMED CT translations
Support local adoption by making SNOMED CT available in your preferred language.
Generate subsets from files that are not ready for publication.
Convert these into reference set files compatible with SNOMED CT.
Manage subsets directly within your extension for easier distribution.
Build simple maps between SNOMED CT and other code systems.
Add, update, and manage map members.
Ensure consistent and interoperable mapping across systems.
Create new concepts with minimal modeling.
Add concepts to your extension without the overhead of full concept authoring tools.
Keep your extension lightweight while addressing local terminology gaps.
Services to help validate and review extension content.
Ensure your release meets SNOMED CT standards.
Package and release your extension as a SNOMED CT Edition.
Publish updates that include both your extension content and the latest International Edition.
The extension must be ready to move into release validation and review
The Review stage begins once validation has completed successfully. At this point, all automated checks have finished and the focus shifts to confirming and understanding the changes that have been made since the last release.
The review stage is used to:
Confirm what content has changed
Check that changes align with the intended scope of work
Identify unexpected or missing changes
Decide whether the content is ready to progress
After validation has run:
The validation process indicator stops spinning
The validation duration is displayed
The time since the last validation run is shown
This confirms that the content is structurally valid and ready to be reviewed.
The primary review tool is the Daily Build summary in the SNOMED CT Browser.
Open the SNOMED CT Browser using the link in the Review box
Select the Daily Build tab
The Daily Build shows a summary of authoring changes since the last release, including:
New concepts
Inactivated or reactivated concepts
Description changes
New reference sets
This view allows reviewers to quickly assess:
The volume of changes
The types of changes made
Whether the changes match expectations for the current work cycle
You can review the detail behind each summary row by selecting it.
When you click a row in the Daily Build report (for example, the row showing the number of New Concepts or Reference Sets with member changes):
The view updates automatically
A detailed list of the relevant components is displayed
Each item is shown with its concept name and SCTID
For example:
Selecting New Concepts displays all concepts added since the last release. Here, you can see that two concepts has been added in the extension. Clicking each of these rows will display the details of the concept in the right side of the browser.
Selecting Reference Sets with member changes displays the reference sets that have been modified. In this example, you see that 5 reference sets have Member Changes.
During review, you should confirm:
All expected changes are present
No unexpected changes appear
Change counts are reasonable for the scope of work
If the review is satisfactory:
The content can move forward to the next workflow stage (frelease preparation)
If issues are identified:
Further authoring may be required
Validation and Review should be re-run after changes are made
For more detailed inspection or for sharing with stakeholders, changes can also be reviewed by downloading a change report.
Change reports are useful when:
A detailed audit is required
Changes need to be reviewed offline
Formal sign-off processes are in place
Dependency Configuration
Video
This video explains how to start a new release cycle in Simplex. - You will learn how to select and upgrade your extension's dependency version to prepare for content development.
Step by Step Instructions
1. Navigate To Manage Edition
To start a new release cycle in Simplex, navigate to the Manage Edition section to begin managing your extension's release cycle.
Navigate To Manage Edition
2. Open Current Editing Site Window
The "Manage Edition" interface shows the different phases of the release cycle - starting with the editing phase. - Steps for preparing the release and publication are grayed out. These steps will be actionable once the new editing process is complete.
Open Current Editing Site Window
3. Review Dependency Configuration
In the editing phase, first set the dependency configuration. -- The parent edition that the extension in this example depends on is the International Edition, January 2024 version.
Review Dependency Configuration
4. Identify New Version Availability
The blue link indicates a new version is available due to one or more releases of the International Edition since the current version.
Start the release cycle by clicking the link to select the new version your extension will depend on.
In this demonstration, we will select the January 2025 version.
Now - Run the dependency upgrade process to set the new version as the dependency for your extension.
The system upgrades the dependency and enters maintenance mode to apply the new version settings. This may take a bit of time.
The new version will be used to validate all artifacts and derivatives within your extension. It will also be the version used for classifying any concepts created in your extension.
Once complete, the new version, such as the January 2025 edition, is set as the dependency.
You are now ready to proceed to the content development phase, where you update all artefacts and derivatives.
For more information, see the related videos on content development and release management.
Add Members to a Map
Demonstration Video
Step-by-Step Instructions
This video shows how to add members to a map in Simplex
1. Introduction
In Simplex, you have created the map derivative, and you can see that no members have been added.
2. Click on the map derivative
Select the map you wish to add members to.
3. Select Snap2SNOMED Map
Notice that Simplex only supports maps created in Snap2Snomed, and you now need to follow the steps outlined.
4. First "Open Snap2Snomed"
First, open Snap2SNOMED
5. Open the map
In Snap2SNOMED, open the map containing the members you want to include in your extension.
Click Export
Select Excel as the export format.
Navigate back to Simplex
Click on 'Choose file', and select the file you just downloaded from Snap2SNOMED.
Click upload data.
After import, you may have to refresh the page, but now you will see that members have been added to your map artifact.
To view the map, click "Open in Browser"
Access the Members section.
Set up an Extension in Simplex
Steps
Description
References
1. Reach out to the Implementation Support Team
To begin using Simplex, the initial setup must be managed by the SNOMED International Implementation Support Team. Follow these steps to get started:
Steps
Description
Validation results show Errors: 0, Warnings: 0 (ideally)
Reference sets Changes
Reference Set member changes
Please refer to the following page of the Extensions Practical Guide for general advice regarding the review and validation of an extension:
Validation Completed
Reviewing Changes Using the Daily Build Summary
How to access the Daily Build
Using the Review to Decide Next Steps
Reviewing via Change Reports
1. Reach out to the Implementation Support Team
Contact the Support Team : Email the Implementation Support Team at implementation@snomed.org to express your interest in using Simplex.
To begin using Simplex, the initial setup must be managed by the SNOMED International Implementation Support Team. Follow these steps to get started:
Contact the Support Team: Email the Implementation Support Team at implementation@snomed.org to express your interest in using Simplex.
Await Response: The team will respond as soon as possible to assist you with the initial setup.
Prepare for Setup: While waiting for a response, you can prepare by completing the tasks outlined below.
2. Aquire a namespace
Before creating an extension, you must obtain a unique namespace identifier from SNOMED International. Follow these steps:
Access the Application Form: Visit the Use SNOMED CT page to access the application form and namespace register.
Submit the Application: Complete and submit the application form as directed.
Receive the Identifier: Once issued, your 7-digit namespace identifier will allow your organization to generate globally unique SCTIDs for your extension components.
3. Determine the module for your extension
Modules in SNOMED CT are used to organize content for maintenance and publication. Follow these steps to determine the name of your module:
Understand Module Requirements: Ensure that all concepts, descriptions, relationships, and reference set members you create will belong to this module.
Select a Descriptive Name: Choose a name that clearly represents the content and purpose of your module.
Forward the Module Name: Once the Implementation Support Team confirms the setup of your extension, forward the chosen module name to them for approval.
This ensures that your module is correctly registered and maintained by your organization.
This guide covered the process of adding members to a map using Snap2SNOMED and Simplex.
Release Management
Overview
Release Management in Simplex ensures that new versions of SNOMED CT Extensions or Editions are delivered in a controlled, consistent, and predictable way.
The release process involves multiple stakeholders and may include third-party contributors. Effective release management ensures that technical, content, and governance aspects of a release are considered holistically, from the end of the Editing cycle through to publication.
Scope of Release Management
In Simplex, Release Management covers all activities required to move an extension from content completion to publication, including:
Release design and configuration
Validation of content and dependencies
Coordination and scheduling of release activities
Review, approval, and publication of releases across environments
These activities ensure that releases are traceable, secure, and aligned with agreed quality standards.
The Release Manager is accountable for ensuring that all content created during the Editing cycle is ready for release in Simplex.
This role acts as the central point of coordination between contributors, validators, and stakeholders, ensuring that content is complete, validated, approved, and suitable for publication.
Key responsibilities include:
Confirming that externally developed content is complete and correctly integrated into Simplex
Managing dependencies and release configuration
Running and reviewing validation checks
Validation and review are central to Release Management in Simplex.
During this phase, the Release Manager ensures that:
Release-level validation is run and passed
Validation findings are reviewed and resolved
All content changes are formally reviewed and approved
Only once these conditions are met can the release progress toward publication.
Successful publication marks the completion of the release cycle and makes the SNOMED CT Extension available for use.
Before publishing a release, the Release Manager ensures that:
The exact scope and content of the release are agreed and finalised
All checks, validations, and approvals have been completed
Communications and stakeholder expectations are managed
Simplex provides structured workflows and controls to support a wide range of release scenarios, from small incremental updates to complex, multi-stakeholder releases, while maintaining consistency and quality. The effort required for Release Management, therefore, depends on factors such as:
The scope and complexity of the release
The volume and type of content changes
The involvement of external contributors or third-party suppliers
Simplex User Guide
Simplex is a lightweight, web-based toolkit from SNOMED International that enables Members and Affiliates to create and manage SNOMED CT extensions quickly, easily, and at no cost.
It is designed for organizations that need a practical and affordable way to tailor SNOMED CT content, such as:
🌍 Translations
📂 Subsets
🔗 Simple maps
🧩 Minimal-modeled concepts
By providing a self-service, online solution, Simplex lowers both technical and financial barriers to extension management, while ensuring your extensions remain standards-compliant and ready for distribution.
Simplex is especially suited to:
Organizations with basic extension needs,
Users who don’t have access to other extension management platforms,
Teams looking for a cost-effective and automated environment for extension release.
Unlike the SNOMED CT Managed Service, which provides a comprehensive, supported solution for complex extension requirements, Simplex is focused on simplicity and independence. It empowers you to work hands-on with your own extension content, without relying on external infrastructure.
Coordinating resolution of issues identified during validation or review
Ensuring that only authorised and approved content progresses through the release cycle
The release meets agreed technical, clinical, and governance requirements
The production environment is protected through formal release controls
This document is a publication of International Health Terminology Standards Development Organisation, trading as SNOMED International. SNOMED International owns and maintains SNOMED CT®.
Any modification of this document (including without limitation the removal or modification of this notice) is prohibited without the express written permission of SNOMED International. This document may be subject to updates. Always use the latest version of this document published by SNOMED International. This can be viewed online and downloaded by following the links on the front page or cover of this document.
SNOMED®, SNOMED CT® and IHTSDO® are registered trademarks of International Health Terminology Standards Development Organisation. SNOMED CT® licensing information is available at . For more information about SNOMED International and SNOMED International Membership, please refer to or contact us at .
Validation is a key step in the Editing Cycle in Simplex. Its purpose is to ensure that all content incorporated into the extension forms a technically valid SNOMED CT Edition package before release preparation can begin.
Simplex runs the full set of SNOMED CT validations provided by SNOMED International. These validations are applied after content from multiple external authoring tools has been compiled into a release structure within Simplex.
Validation helps identify issues early, ensures consistency across content types, and protects the quality of the final release.
Please refer to the following page of the Extensions Practical Guide for general advice regarding the review and validation of an extension:
Video
Running Validation
Validation is initiated directly from the Editing stage.
To run validation:
Navigate to Manage Edition.
In the Editing stage, locate the Validation box.
Click Run validation.
Once started, Simplex executes the full validation suite against the current state of the compiled extension content.
The Editing cycle cannot progress until validation has completed and all blocking issues have been resolved.
Simplex applies the standard SNOMED CT validation rules, also applied for the International Edition of SNOMED CT: This includes checks that:
Assert referential integrity between components (for example, ensuring references point to valid concepts)
Validate terms and descriptions, including:
Detection of duplicate terms within a hierarchy
Some validation rules also assert Machine Readable Concept Model (MRCM) constraints. While Simplex does not support stated modelling directly, these rules are still be included as part of the standard validation set and applied where relevant.
Once validation completes, the results are displayed in the right-hand panel of the screen.
Validation issues are categorised as:
Errors
Issues that prevent the release from progressing. All errors must be fixed before release preparation can be completed.
Warnings
Issues that do not necessarily block the release but should be addressed to improve content quality.
A summary count of errors and warnings is shown at the top of the results panel.
The validation results panel provides a detailed, actionable view of identified issues.
For each issue, Simplex displays:
The component identifier (for example, a Concept ID)
The assertion text, which is a human-readable explanation of the issue
Links that allow the user to explore the affected component in context
Users can click on component IDs to open the Simplex Browser, making it easier to understand where and why the issue occurs.
A help link titled “How to fix these errors and warnings?” is available to provide additional guidance on interpreting and resolving validation findings.
Simplex acts as a validation and coordination platform; it does not directly edit content.
All validation issues must be fixed in the original authoring tool where the content was created, for example:
Subset issues are fixed in the Refset and Translation Tool Editor
Mapping issues are fixed in Snap2SNOMED
Translation issues are fixed in the SNOMED CT Translation Tool
Simplex clearly identifies which components are affected, helping contributors locate and correct issues efficiently.
After issues have been fixed in the source tools:
Updated content must be re-imported into Simplex.
Validation must be run again from the Editing stage.
This cycle continues until all errors are resolved and the content meets the required quality threshold.
Validation results can be downloaded directly from the results panel.
Downloaded reports can be shared with:
Content editors
Subject matter experts
External contributors
This supports collaborative issue resolution and ensures that all stakeholders have clear visibility of required fixes.
The Validation step in the Editing Cycle is considered complete when:
Validation has run successfully
All errors have been resolved
Any remaining warnings have been reviewed and addressed where appropriate.
Once validation is complete, the extension is ready to progress to release preparation.
Create a New Translation in Simplex
First, create the Language Reference Set by following these steps:
This guide will walk you through creating a translation in Simplex.
Create a new artifact by clicking on "New Artifact".
Navigate to the right side of the screen to select the type
Access the translation feature by clicking on "Translation".
Identification of invalid characters or formatting issues
Ensure consistency and correctness across release files
Concept or spreadsheet-based content is corrected at source
What is Validated?
Validation Results and Issue Types
Understanding Validation Results
Fixing Validation Issues
Re-running Validation After Fixes
Downloading and Sharing Validation Results
Completion of the Validation Step
Select the preferred term by clicking on "Preferred term".
Enter the name you want for your language reference set
Navigate to the desired location by clicking on the specified area.
Confirm that the artifact is created
In this example, we are using the Refset and Translation tool.
In this guide, you will learn how to efficiently add members to your subset using Simplex. These steps will guide you through the steps required to add the members you have specified in your subset in the Reference Set and Translation Tool.
1. Select the subset you want to add members to
From the list of created subsets, which are displayed in the list to the left of the screen, select the subset you want to add members to.
2. Select 'Refset Tool Subset' as the source
Navigate to "refsetToolSubset" section.
3. Click "Open Refset and Translation Tool"
Navigate to the right of the screen, where you see the options to select the source for your subset. Here, select "Refset Tool Subset"
4. Click "Refset"
In the Refset and Translation Tool, select the "Refset" tab.
From your list of available subsets, select the subset containing the members you want to export.
Click the download icon to initiate the export.
Start the export process by clicking "Export". - a file is now available in your downloads folder on your machine
Return to Simplex, and select the option to "Choose File." Now, select the file you just exported.
Proceed by clicking on "Upload data."
Once imported, number of imported members are shown in braces.
To view the subset and its members, click "open in browser"
Click the "Members" tab to see the members of your subset.
5. Select the subset containing the members you want to export
6. Click here to download
7. Click "Export"
8. Click "Choose File"
9. Click "Upload data"
10. View Subset
11. To view the subset, click "open in browser"
12. Click the "Members" tab to see the members of your subset
