Systems and methods for personalized sizing codes

A system comprising:

• a user device including a memory storing processor-readable instructions and a processor configured to execute the processor-readable instructions to perform operations that include:
• detecting, via an extension operating on the user device, a user interaction with a first item on a platform interface, the first item corresponding to a first item entity;
• transmitting, to a size engine, an indication of the user interaction;
• receiving, from the size engine, a size code for the first item, the size code having been determined based on a first size profile associated with a first user of the user device, wherein the first size profile correlates a size for each item entity to each other item entity of a plurality of item entities;
• and
• modifying, via the extension, code associated with the platform interface based on the size code.

A method comprising:

• detecting, via an extension operating on a user device, a user interaction with a first item on a platform interface, the first item corresponding to a first item entity;
• transmitting, via the extension, an indication of the user interaction to a size engine;
• receiving, from the size engine, a size code for the first item, the size code having been determined based on a first size profile associated with a first user of the user device, wherein the first size profile correlates a size for each item entity to each other item entity of a plurality of item entities, and wherein the size code comprises a size-agnostic indicator;
• and
• generating, via the extension, a notification on the user device including the size-agnostic indicator.