CodeFactor.io
JSLint
Codacy
ESLint
Coala
textlint
Prettier
Online Javascript Validator validates javascript code and find errors and warnings that can be fixed. See real time validation of your javascript code as you type.

JSONFormatter.org
JSONLint
CodeBeautify
FreeFormatter
10015.io
DevPicker
DevSolvev2
Browser-based developer tools for JSON, text, encoding, hashing, DNS and SEO tasks. No account needed.

Which is more popular?
Based on our record, Javascript Validator seems to be more popular. It has been mentioned 2 times since March 2021.
Website, pricing, platforms and company facts side by side.
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Javascript Validator
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| Website | beautifytools.com | trexmi.com |
| Pricing | — | |
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In their own words, as submitted to SaaSHub.

No description of Javascript Validator yet.
Trexmi is a collection of 227 focused developer utilities that run in the browser, with no account required for everyday use. Most tools process data locally: JSON formatting, validation, sorting and conversion; text transforms, counters and extraction; Base64, URL and HTML encoding; hashing and...
What each product offers, as listed by its team.

No features have been listed yet.
How often each product is chosen within a category, 0–100% relative to the other.

As answered by people managing Javascript Validator and Trexmi.
Trexmi's answer:
Two things. First, most tools run entirely in the browser — JSON, text, encoding, hashing and regex never send input to a server, so there is no upload step and no round trip. Second, every utility has its own page with worked examples and notes on edge cases, rather than a single dashboard hiding 200 tools behind a dropdown. Its text-processing core has been extracted and released separately under MIT.
Trexmi's answer:
If the work is a one-off format or decode, most established tools handle it fine. Trexmi is a better fit when the data should not leave the machine, when the payload is large enough that a server round trip is noticeable, or when the task is newer than the incumbents cover — MCP tool schemas, OpenAI function schemas, JSON to Zod or Pydantic, cURL conversion. It is also signup-free with no daily limits on local tools.
Trexmi's answer:
Developers and technical staff doing everyday data work: inspecting API responses, converting between formats, generating types from JSON, decoding tokens, checking DNS and TLS, and validating sitemaps or structured data. Also people building on LLMs who need tool schemas and token estimates.
Trexmi's answer:
It started as a set of scripts kept around for repeated tasks — formatting JSON, converting feeds, cleaning text — and turned into a site once the same problems kept coming back. The processing later moved from the server into the browser, which removed the latency and meant the data no longer had to be trusted to anyone. That port was verified byte for byte against the original PHP and released as an open-source library.
Trexmi's answer:
PHP on the server, vanilla JavaScript on the client with no framework, WordPress as the content and routing layer. Browser-side processing uses standard platform APIs — Intl.Segmenter for grapheme handling, TextEncoder for UTF-8, Web Crypto where hashing is done locally.
Share your experience with using Javascript Validator and Trexmi. For example, how are they different and which one is better?
Recommendations tracked on public social media and blogs since March 2021.

Try pasting your code into a validator to see if you don't have a typo somewhere: https://beautifytools.com/javascript-validator.php. Source: over 4 years ago
So everything works fine the way I see it and that error only comes up after a few clicks. Since I'm not a js wizard I did put your script code into a javascript validator and it looks like you're missing a couple of semi colons here and... Source: almost 5 years ago
Tracking Trexmi since Sep 2026.
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