
Notion
Logseq
Joplin
Evernote
Roam Research
Bear
Typora
A second brain, for you, forever. Obsidian is a powerful knowledge base that works on top of a local folder of plain text Markdown files.

Abstract APIs
Numverify
GlobalEntity API
mailboxlayer API
IBAN.com
VAT-calc.net
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.

Which is more popular?
Based on our record, Obsidian seems to be more popular. It has been mentioned 1526 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | obsidian.md | isvalid.dev |
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| Platforms | — | |
| Company | Startup from the United States | — |
| Listed in |
In their own words, as submitted to SaaSHub.


No description of Obsidian yet.
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),...
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
Walkthroughs and reviews on video.
OBSIDIAN: Getting Started, Facts & Pricing
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How often each product is chosen within a category, 0–100% relative to the other.


As answered by people managing Obsidian and IsValid.dev.
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 Obsidian and IsValid.dev. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


One thing to note: Notion bills itself as an Evernote competitor for personal users. It can be—but it's too much for most people, and its offline functionality isn't the best. If you love the idea of Notion, go right...
This app is the kind of thing that, if you’re into it, will have you exploring its various ins, outs, and add-ons for days and weeks on end. Obsidian uses the Markdown format for its notes (which means they can be...
However, it's important to note that Obsidian's whiteboard functionality is not as robust as dedicated collaboration tools. While it lacks real-time basic collaboration features, Obsidian compensates with its vibrant...
We have no reviews of IsValid.dev yet. Be the first one to post
Recommendations tracked on public social media and blogs since March 2021.


For note-taking, I recommend Obsidian. It's lightweight, has a large community, and offers plenty of useful plugins. I use the Timekeep plugin myself, which helps me connect tasks with the time spent on them. - Source: dev.to / about 18 hours ago
The setup that makes the output noticeably sharper is a memory layer. Connecting a plain-text notes app like Obsidian (free for personal use) gives the agent durable context: what your project is about, who it is for, and what you have... - Source: dev.to / about 2 months ago
The vault is compatible with Obsidian because the files are just Markdown, YAML frontmatter, and standard relative links. - Source: dev.to / 29 days ago
Tracking IsValid.dev since Apr 2026.
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Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.
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Official company data from 50+ European business registers plus GLEIF LEI — one REST API for KYB, compliance and firmographic enrichment
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