
Postio.co.uk
Ideal postcodes
Fetchify
Smarty
Data8 UK
ZIP Code API
Data8 UK PredictiveAddress
The most affordable postal code API. 240+ countries, sub-5 ms responses. Simple, elegant, transparent.

The modern platform for creating, sharing, and collaborating on AI prompts. Advanced version control and real-time testing.
Website, pricing, platforms and company facts side by side.
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| Website | postaldatapi.com | diffyn.com |
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| Company | Startup from the United States · 1 - 9 employees · 2026 | — |
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In their own words, as submitted to SaaSHub.


PostalDataPI is a global postal code validation and enrichment API covering 240+ countries and territories. One API, one key, one flat rate — $0.000028 per query with no tiers or subscriptions. What you get back: Up to 18 metadata fields per postal code — city, state/region, coordinates,...
No description of Diffyn yet.
What each product offers, as listed by its team.


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An editorial look at what each product does well and who it suits.


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Why this product is good
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Overall verdict
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Walkthroughs and reviews on video.
PostalDataPI Now Returns 18 Fields Per Postal Code — for 240+ Countries
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The Ultimate Prompt Tool for Creators – Visualize & Organize with Diffyn
How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing PostalDataPI and Diffyn.
Diffyn's answer:
Addresses workflow and change management on LLM prompts, provide teams with traceability and visualization of tests across multiple models, provide deeper understading into efficiency of these prompts.
Diffyn's answer:
Diffyn is the platform that specializes on both change management and multi-model analysis.
Diffyn's answer:
React, Next.js, POSTGRESQL
Diffyn's answer:
Professionals incorporating LLMs or AI tools in their workflow and wants to keep track of changes and test their prompts.
Diffyn's answer:
I started working on Diffyn when I notice that prompting has become an essential part of work across many industries. While there are version control platofrms like github, they are not designed for just prompt management are can be overkill such applications, it is also not integrated natively with various LLMs and relevant tools for users to validate ideas and visualise results properly.
Share your experience with using PostalDataPI and Diffyn. For example, how are they different and which one is better?
When comparing PostalDataPI and Diffyn, you can also consider the following products.

Fast UK address, email & phone validation APIs for developers. Official Royal Mail PAF data. Pay as you go, 100 free lookups.
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We help businesses improve UX and data quality with a cutting edge address validation service.
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Fetchify delivers fast, accurate address, email, phone and bank validation tools that help businesses capture clean, verified customer data, reduce failed deliveries and improve checkout experiences worldwide.
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Smarty provides address validation, autocomplete, geocoding and reverse geocoding services covering addresses in over 240+ countries.
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Build Confidence in your data with Data8. We are the UK's Premier Data Solutions Provider for all your data validation needs, Contact us today for more information.
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REST API for US ZIP, ZIP+4, and Canadian postal codes. Single unified endpoint covers address validation and standardization, radius search (centroid haversine and true spatial polygon intersection), point-to-point distance, autocomplete/typeah
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