Srilankan55zip -

Use a lightweight Node.js/Express service or a Python/Flask endpoint to serve the mapping.

A simple onChange event listener on the zip code input field to trigger the fetch request. srilankan55zip

Query a local dataset or an API like srilankan-postalcode to match the code to its corresponding city. Use a lightweight Node

Use Regex to ensure the input is exactly 5 numeric digits (e.g., ^(\d{5})$ ). srilankan55zip

To develop a feature around (often colloquially referred to as "ZIP codes" despite being a 5-digit numeric system), you should focus on a Postcode-to-Location lookup or Address Validation tool.