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

Human Benchmark
reaction-time-test.io
Human-Benchmark.org
Click Speed Reaction Time Test
ClickingTests
Click Speed Test
ReactionTimeTest.net
Reaction Time Test - Measure Your Response Speed Online

Which is more popular?
Based on our record, Reaction-Time-Test.org seems to be more popular. It has been mentioned 1 time since March 2021.
Website, pricing, platforms and company facts side by side.
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ZIP
ZIP Code API
|
|
|
|---|---|---|
| Website | zip-codes.com | reaction-time-test.org |
| 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 Reaction-Time-Test.org 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
How often each product is chosen within a category, 0–100% relative to the other.

As answered by people managing ZIP Code API and Reaction-Time-Test.org.
Reaction-Time-Test.org's answer:
The overall experience is better
Reaction-Time-Test.org's answer:
5 rounds of testing are more accurate, completely free, multilingual
Share your experience with using ZIP Code API and Reaction-Time-Test.org. For example, how are they different and which one is better?
Recommendations tracked on public social media and blogs since March 2021.

Tracking ZIP Code API since May 2026.
I run Reaction Time Test, a browser-based tool with a five-round visual test and additional clicking, memory and aiming activities. This article describes a general design approach for similar interfaces; it is not a claim about the... - Source: dev.to / about 1 month ago
When comparing ZIP Code API and Reaction-Time-Test.org, you can also consider the following products.

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A web game to benchmark your brains.
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Free Zip Code API - Free Postal Code Validation | Zipcodestack
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How fast are your reflexes? Take the reaction time test and find out your speed in milliseconds.
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The most affordable postal code API. 240+ countries, sub-5 ms responses. Simple, elegant, transparent.
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Test your brain power with human benchmarks. Access reaction time tests, sequence memory tests, aim trainer and more to understand your cognitive strengths and weaknesses.
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