
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.

GitBook
Mintlify
Docusaurus
Archbee.io
Postman
Swagger UI
Slite
A collaborative developer hub for your API or code.

Which is more popular?
Based on our record, ReadMe seems to be more popular. It has been mentioned 28 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | postaldatapi.com | readme.com |
| Pricing | ||
| Company | Startup from the United States · 1 - 9 employees · 2026 | — |
| Listed in |
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 ReadMe yet.
What each product offers, as listed by its team.


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


Overall verdict
Why this product is good
Recommended for
Overall verdict
Why this product is good
Recommended for
ReadMe is recommended for tech companies, API developers, software development teams, product managers, and any organization that needs to create, maintain, and improve the usability of their API documentation. It is particularly beneficial for teams that prioritize collaborative documentation processes and wish to offer users a modern documentation interface.
Walkthroughs and reviews on video.
PostalDataPI Now Returns 18 Fields Per Postal Code — for 240+ Countries
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How often each product is chosen within a category, 0–100% relative to the other.


Share your experience with using PostalDataPI and ReadMe. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


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Readme.com is a developer hub that allows users to publish API documentation. It focuses on making API references interactive by allowing to Try out API calls, log metrics about the API call usage, and more. This...
ReadMe offers integration with apps like Slack, Google Analytics, and Zendesk. One of its most significant advantages is the metrics option which lets you see how customers are using your API.
Recommendations tracked on public social media and blogs since March 2021.


Tracking PostalDataPI since Apr 2026.
ReadMe specializes in creating stunning developer experiences. If your API’s success depends on attracting external developers, ReadMe’s polish and developer-centric features deserve consideration. - Source: dev.to / 11 months ago
In this comparison, we examine four leading platforms: Theneo's AI-first approach with complete developer portals, Redocly's spec-governance excellence, ReadMe's content-centric hubs, and Mintlify's beautiful Git-native design. We'll... - Source: dev.to / 10 months ago
ReadMe is fantastic for API documentation specifically. The interactive API explorer is genuinely impressive. But if you need more than API docs; tutorials, conceptual guides, getting started content, it starts to feel like you're... - Source: dev.to / 10 months ago
When comparing PostalDataPI and ReadMe, 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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Modern Publishing, Simply taking your books from ideas to finished, polished books.
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We help businesses improve UX and data quality with a cutting edge address validation service.
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The AI-powered documentation writer. It's documentation that just appears as you build
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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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Easy to maintain open source documentation websites
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