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

Doodle
When2Meet
Crab Fit
Framadate
LettuceMeet
Calendly
Xoyondo
Find the best time to meet. Coordinate group meetings without the back-and-forth emails.

Which is more popular?
Based on our record, Rallly seems to be more popular. It has been mentioned 8 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 | rallly.co |
| Pricing | — | |
| Company | Startup from the United States · 2026 | 2015 |
| 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...
Rallly is an open-source scheduling and collaboration tool designed to make organizing events and meetings easier.
What each product offers, as listed by its team.

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

Overall verdict
Why this product is good
Recommended for
No analysis of Rallly yet.
How often each product is chosen within a category, 0–100% relative to the other.

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

We have no reviews of ZIP Code API yet. Be the first one to post
Rallly (with three Ls) is an appointment scheduler with classic polling functionality where the members of your group can vote on the best times for the meeting or event. I like that Rallly’s voting feature is...
The main drawback to Rallly is it only lets you suggest dates, not times. It doesn't have any management tools or advanced scheduling features, either, much less offer connectivity with your calendar. But it does...
Recommendations tracked on public social media and blogs since March 2021.

Tracking ZIP Code API since May 2026.
It is great that WAYF offers something completely bare one without the features you are mentioning, IMHO. https://rallly.co/. - Source: Hacker News / almost 3 years ago
Hi everyone. Just wanted to share an update from my original post a while back about my self-hostable Doodle alternative called Rallly. I released a new version with an updated UI and a lot of highly requested features. For a while this... Source: about 3 years ago
Https://rallly.co/ is great for scheduling consensus. It's Doodle before Doodle fell off. Not a lot of dates here obviously, but when you blow up and start an army of trash goblins you'll probably need it. Source: over 3 years ago
When comparing ZIP Code API and Rallly, 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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Make meetings happen. With Doodle, scheduling becomes quick and easy.
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Free Zip Code API - Free Postal Code Validation | Zipcodestack
Compare Zipcodestack to ZIP Code API or Rallly:

When2meet helps you find the best time for a group to get together. It is a free survey tool that is quick and easy to use.
Compare When2Meet to ZIP Code API or Rallly:

The most affordable postal code API. 240+ countries, sub-5 ms responses. Simple, elegant, transparent.
Compare PostalDataPI to ZIP Code API or Rallly:

Use your availability to find a time that works for everyone
Compare Crab Fit to ZIP Code API or Rallly: