Smarty
Zipcodestack
PostalDataPI
Geoco.io
Melissa Data Quality
Loqate
usZIPCodes.org
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

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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ZIP
ZIP Code API
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|---|---|---|
| Website | zip-codes.com | readme.com |
| Pricing | — | |
| Company | Startup from the United States · 2026 | — |
| Listed in |
In their own words, as submitted to SaaSHub.

API for US ZIP, ZIP+4, and Canadian postal code data. One unified endpoint set covers North America — no separate APIs by country or data type. What it does Address validation and standardization — production-grade parser with ZIP+4 append, refreshed monthly Radius search — centroid haversine and...
No description of ReadMe yet.
What each product offers, as listed by its team.

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.
How often each product is chosen within a category, 0–100% relative to the other.

Share your experience with using ZIP Code API 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 ZIP Code API since May 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 ZIP Code API and ReadMe, you can also consider the following products.

Smarty provides address validation, autocomplete, geocoding and reverse geocoding services covering addresses in over 240+ countries.
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Modern Publishing, Simply taking your books from ideas to finished, polished books.
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Free Zip Code API - Free Postal Code Validation | Zipcodestack
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The AI-powered documentation writer. It's documentation that just appears as you build
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The most affordable postal code API. 240+ countries, sub-5 ms responses. Simple, elegant, transparent.
Compare PostalDataPI to ZIP Code API or ReadMe:

Easy to maintain open source documentation websites
Compare Docusaurus to ZIP Code API or ReadMe: