What are the most important things to consider when developing a custom application in ServiceNow?

[SuhebM]

If you want to create a new application in ServiceNow, what things should you think about before you start building it?

[Dr Atul G- LNG]

Hi @SuhebM 

When developing a custom application in ServiceNow, the most important factor is designing for upgradeability by using the proper application scope and avoiding modifications to baseline system tables.

Architecture and Scope

• Application Scope: Keep your custom app in a private scope (e.g., x_company_app) to protect your code and prevent naming conflicts with system updates.

• Access Controls: Set up clear Access Control Lists (ACLs) to control who can read, write, or create data in your application tables.

• Data Model: Design custom tables carefully. Prefix custom table names correctly and reuse existing baseline fields or tables when possible.

Coding and Performance

• No-Code / Low-Code First: Use built-in tools like Flow Designer and Playbooks before writing custom server-side scripts.

• Scripting Best Practices: Avoid writing scripts in client-side code where possible. Keep server-side scripts efficient by using GlideRecord queries safely and avoiding loops that query the database repeatedly.

• Scoped APIs: Use scoped script APIs instead of global ones to ensure your application remains compatible with future platform releases.

Testing and Maintenance

• Automated Test Framework (ATF): Build tests using ATF so you can quickly check your application functions correctly after platform upgrades.

• Update Sets / Source Control: Manage your development work using standard Update Sets or link your application to a source control repository like Git.

https://mynow.servicenow.com/now/best-practices/assets/what-are-the-best-practices-for-customization

[Ankur Bawiskar]

@SuhebM 

Securing your app is the primary thing as you have considered building custom app to segregate things
what's your exact question?

refer below links

Application Development - Best Practice #1 - Work in a scope 

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