Benefits and Guidelines for using a Prefix or Suffix

In your extension, the name of each new application object (table, page, codeunit), must contain a prefix or suffix. This rule applies to all objects. You can use the Caption values for what you decide to display to the user. When you modify a core Dynamics 365 object using a table extension or a page extension, the prefix/suffix must be defined at the control/field/action/group level.


Declare your objects with a prefix as shown in the following examples.


table 70000000 MyPrefixSalesperson
table 70000001 SalespersonMySuffix


page 70000000 MyPrefixSalesperson
page 70000001 SalespersonMySuffix

Page extension



codeunit 70000000 MyPrefixSalesperson
codeunit 70000001 SalespersonMySuffix


Apps in AppSource are required to register and use a prefix or a suffix. Only in vary rare cases will apps run into naming conflicts.

Per-tenant extensions are not required to use a prefix or suffix, but we strongly recommend that you do so. You can use pte as prefix or suffix to avoid conflicts with AppSource apps or base objects.


If your per-tenant extension causes a conflict with a new object in the base application or an updated AppSource app, then the per-tenant extension will be required to make the change.

General rules

  • The prefix/suffix must be at least 3 characters
  • The object/field name must start or end with the prefix/suffix
  • If a conflict arises, the one who registered the prefix/suffix always wins
  • For your own pages/tables/codeunits, you must set the prefix/suffix at the top object level
  • For pages/tables in the base application or other apps that you extend, you must set the prefix/suffix at the top object level and also at the control/field/action level
  • Use the AppSourceCop tool to find all missing prefixes and/or suffixes. Configuration options for this tool can be found here. The Rules section explains the different checks that the analyzer will do. For prefix/suffix detection, refer to the Configuration section. It explains how to set your prefix in the AppSourceCop.json file.

Examples – per-tenant extension

Let's say that you're creating a per-tenant extension, myext and you want to future-proof the naming by applying the prefix or suffix pte, which you are not required to register.

Let's look at some examples:

Prefixes Suffixes
pte-myext-salespersoncode salespersoncode-myext-pte
pte_myext_salespersoncode salespersoncode_myext_pte
pte myext salesperson code salesperson code myext pte
pteMyExtSalesPersonCode SalesPersonCodeMyExtPte

Examples - AppSource app

Alternatively, let's say your company is Fabrikam, and you're building an app called Rentals. First thing, you email and register fab as your company affix.


It is always a good idea to supply a few suggestions in priority order to avoid back and forth communication.


For AppSource validation file names are not enforced; only object names.

A registered affix must be 3 letters, no more, no less, and you must provide the publisher name, which you will be using in app.json when you apply for an affix.

Once you get confirmation from Microsoft, you are free to use object and field names that start with fab or end with fab. Here are some examples:

Prefixes Suffixes
fab-salespersoncode salespersoncode-fab
fab_salespersoncode salespersoncode_fab
fab salespersoncode salespersoncode fab
FabSalesPersonCode SalesPersonCodefab

At Fabrikam, another team is building another app, so you request a special affix for your app so that the two Fabrikam apps can be kept apart. In this scenario, you do not have to register anything with Microsoft, as long as you do this with your company affix. Here are some examples:

Prefixes Suffixes
fab-rentals-salespersoncode salespersoncode-rentals-fab
fab_rentals_salespersoncode salespersoncode_rentals_fab
fab rentals salesperson code salesperson code rentals fab
FabRentalsSalesPersonCode SalesPersonCodeRentalsfab

In this scenario, your appSourceCop.json configuration will specify something like fab-rentals and rentals-fab as values for mandatoryaffixes, even though only fab was registered with Microsoft.


You are not required to change any already registered affixes; you can continue using these affixes. The guidelines above only apply to new registrations.


Contact us at to reserve the prefix/suffix of your choosing.

See Also

Checklist for Submitting Your App
Rules and Guidelines for AL Code