About three years ago, I built a Power Apps Component Framework (PCF) control focused on one specific job: validating UK postcodes without depending on any external API.
If your project has strict security/network restrictions or you want to avoid recurring API costs, this approach is a practical alternative.
Why I built it
In many enterprise projects, outbound API calls are either:
- blocked by policy,
- heavily reviewed and delayed,
- or avoided to reduce ongoing costs.
For address flows, postcode validation is usually one of the first things that triggers an external dependency. I wanted a lightweight component that could validate format and user input quality entirely in-app.
What the component does
The control provides:
- UK postcode format validation
- Real-time user feedback while typing
- Easy integration into model-driven or canvas app scenarios where PCF is used
- No external API dependency for validation logic
Because it validates locally, it is well-suited for environments where data residency, firewall, or procurement constraints make third-party API usage difficult.
In action
Example of the PCF control providing immediate visual feedback for invalid vs valid UK postcodes in model-driven and canvas apps.
Where to find it
- PCF Gallery: UK Postcode Validation
- GitHub (source and implementation details): ChayeNovak/UKPostcodeValidation
When to use this approach
This component is a strong fit when:
- You only need postcode validity checks, not full address lookup.
- Your solution must work with no internet/external calls.
- You want to keep operational costs predictable and low.
If your requirement expands into full address auto-complete or geocoding, you may still need an external provider. But for many business forms, postcode validation alone provides most of the immediate value.
Final thoughts
This was one of those components built to solve a very real delivery constraint—and it has remained useful because that constraint is common in enterprise Power Platform projects.
If you’re building in a controlled environment and need reliable UK postcode validation, this PCF control is a simple and practical option.