
ZIP Code API
ZipCheckup
PostalCodes.info
Smarty
Geocode.xyz
Geoco.io
getAddress.io
Free Zip Code API - Free Postal Code Validation | Zipcodestack

NovoPsych
Clinical assessment tools for psychologists, therapists and occupational therapists. Send measures by secure link and review scored results, severity bands and reports.

Which is more popular?
Based on our record, Zipcodestack seems to be more popular. It has been mentioned 3 times since March 2021.
Website, pricing, platforms and company facts side by side.
|
|
|
|
|---|---|---|
| Website | zipcodestack.com | clientforms.app |
| Pricing | ||
| Platforms | — | |
| Listed in |
In their own words, as submitted to SaaSHub.


No description of Zipcodestack yet.
Clinical assessment tools for psychologists, therapists and occupational therapists. Send measures such as the PHQ-9, GAD-7 and DASS-21 by secure link and get scored results, severity bands and reports ready to review. The catalogue also includes DSM-5 ADHD assessments and autism screening tools....
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 Zipcodestack and ClientForms.app.
ClientForms.app's answer:
Frontend: Next.js 15 (React 19), Tailwind CSS Backend: Supabase (PostgreSQL, Row-Level Security) Authentication: Clerk Payments: Stripe Hosting: Vercel (Sydney region) Database hosting: Supabase (Australian data residency)
ClientForms.app's answer:
Psychologists who assess ADHD and autism. Typically private practice, solo or small group (1-5 clinicians), currently using paper forms and spending hours on admin per assessment. They want something that works and is secure.
ClientForms.app's answer:
Neurodivergent-first design. Most digital forms just replicate paper online. ClientForms is built specifically for ADHD and autism patients - progress bars with time remaining (helps with time blindness), softer colours instead of harsh white, sticky headers so you always know where you are. The forms are designed to reduce anxiety and improve completion rates.
ClientForms.app's answer:
Most clinical software treats patients as an afterthought. ClientForms is designed specifically for neurodivergent users who are filling out the forms, progress indicators, time estimates, calmer colours, predictable layouts. One link, no signup required, works on any device. Patients just open and complete.
Share your experience with using Zipcodestack and ClientForms.app. For example, how are they different and which one is better?
Recommendations tracked on public social media and blogs since March 2021.


Using the zipcodestack API in your Node.js application is straightforward. You’ll first need to sign up for a free API key (it only takes a minute). Once you have your API key, you can call the REST endpoints using any HTTP client. Below... - Source: dev.to / about 1 year ago
Zipcodestack - Free Zip Code API and Postal Code Validation. Ten thousand free requests/month. - Source: dev.to / almost 3 years ago
I have seen this request pop up quite a few times. I did a quick search for free APIs of zipcode lookups. This one, named "zipcodestack" (I'm not in any way tied to, endorsing, or promoting them) seemed like a pretty good resource with... Source: over 3 years ago
Tracking ClientForms.app since Dec 2025.
When comparing Zipcodestack and ClientForms.app, you can also consider the following products.
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
Compare ZIP Code API to Zipcodestack or ClientForms.app:

NovoPsych is a tool that is used for outcome monitoring via conducting psychological tests online.
Compare NovoPsych to Zipcodestack or ClientForms.app:

Check water quality, product recalls, energy rebates, and safety alerts for any U.S. ZIP code. Free reports powered by EPA and government data.
Compare ZipCheckup to Zipcodestack or ClientForms.app:
Postal code lookup API and downloadable country datasets for address validation, checkout, logistics and geocoding workflows.
Compare PostalCodes.info to Zipcodestack or ClientForms.app:

Smarty provides address validation, autocomplete, geocoding and reverse geocoding services covering addresses in over 240+ countries.
Compare Smarty to Zipcodestack or ClientForms.app:

A geoparser, geocoder and batch geocoder for the world. Map your data.
Compare Geocode.xyz to Zipcodestack or ClientForms.app: