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Melissa Data Quality
A powerful REST API for validating emails, IBANs, BIC/SWIFT codes, LEI, ISIN, credit cards, VAT numbers, phone numbers, and 70+ more validators. Free tier available.

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Calm.com can help you reduce stress and increase calm.

Which is more popular?
Based on our record, Calm 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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| Website | isvalid.dev | calm.com |
| Pricing | — | |
| Platforms | — | |
| Company | — | Startup from the United States |
| Listed in |
In their own words, as submitted to SaaSHub.


IsValid is a validation API service for developers who need to quickly verify data formats without building their own validators. It offers 40+ endpoints covering financial identifiers (IBAN, BIC, ISIN, CUSIP), international standards (ISBN, ISSN), technology formats (UUID, JWT, QR codes),...
No description of Calm 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
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Calm App Review 2020: A Psychologist's Honest Opinion
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How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing IsValid.dev and Calm.
IsValid.dev's answer
IsValid offers 70+ validators in a single API — covering financial identifiers (IBAN, BIC, ISIN, LEI), international standards (ISBN, ISSN), technology formats (UUID, JWT, QR codes), tax numbers (VAT, REGON, PESEL), credit cards, phone numbers, and more. No need to integrate multiple services for different data types.
IsValid.dev's answer
Most validation APIs focus on one category (email or phone). IsValid covers financial, regional, and technical formats all in one place with a consistent REST API. The free tier with 100 calls/day requires no credit card, and integration takes minutes.
IsValid.dev's answer
Developers and software teams building applications that handle user input, financial data, or international identifiers — particularly in fintech, e-commerce, and SaaS products.
IsValid.dev's answer
IsValid was built out of frustration with piecing together multiple validation libraries and services. The goal was a single, reliable API that handles the full range of data validation needs developers encounter in real-world applications.
IsValid.dev's answer
Next.js, Fastify, PostgreSQL, Docker
Share your experience with using IsValid.dev and Calm. 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 IsValid.dev yet. Be the first one to post
What's keeping you up at night? Anxious thoughts? Lack of focus? A stressed-out psyche? Calm’s guided meditations will have you sleeping soundly and feeling more relaxed almost instantly. When we tried Calm, we were...
With over 4.5 million subscribers, Calm is a meditation and mindfulness app that specializes in sleep meditations and sleep stories for adults and children. Some of these stories are narrated by popular celebrities,...
Ten Percent Happier is not a cheaper alternative to Headspace or Calm, exactly—the annual membership is $99—but it’s certainly better than both of those options when it comes to targeted meditation training. The app...
Recommendations tracked on public social media and blogs since March 2021.


Tracking IsValid.dev since Apr 2026.
Meditation. try the calm app or calm.com for sleep stories or sleep body scans. Source: over 3 years ago
If I purchase the Calm membership through the app store, will the rebate still post? I saw in the details it specified "calm.com." Does anyone know for sure? Source: almost 4 years ago
I found Waking Up to require more effort than calm.com (or headspace). The latter apps tend to focus on simple things: e.g. Focus on your breathing whereas Waking Up is actually much more about challenging your beliefs of what it even... Source: about 4 years ago
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