Built by a developer, for developers

The developer behind this site

My name is Pankaj Kumar. I'm a Senior Software Engineer based in Bangalore, India. I have been writing production C# professionally since 2022, working across ASP.NET Core, Blazor (Server and WebAssembly), Entity Framework Core, and Azure-hosted services. My day job involves building and maintaining web APIs, Blazor applications, and Azure-hosted services for enterprise clients.

Most of my actual work hours involve the small but time-consuming tasks that every .NET developer faces: formatting a minified JSON response from a third-party API, decoding a JWT to check why validation is failing, converting a Unix timestamp to a human-readable date, or testing a regex before it goes into production. These tasks take 30 seconds each with the right tool and 10 minutes each without one.

I built DevToolsHub because the tools I was using were consistently slow, covered in ads, or required me to paste sensitive data — JWT tokens, API keys embedded in JSON payloads, private key hashes — into sites I had no visibility into. I wanted tools I could use at work without second-guessing where my data was going. That's the site you're using now.

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Tools I use daily

Here's what's actually running on my machine during a typical working day:

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What DevToolsHub is

DevToolsHub is a free collection of browser-based developer utilities at www.devtoolshub.info. Every tool does one thing well: accept developer input, process it correctly, and return the result immediately.

• Formatting — JSON, YAML, HTML, CSS, SQL, and XML formatters that handle real-world messy input
• Security & Auth — JWT decoder, JWT generator, JWT secret generator, password generator
• Encoding & Hashing — Base64, URL encoder, HTML entity encoder, MD5/SHA-1/SHA-256/SHA-512 generator
• Conversion — Unix timestamp converter, CSV to JSON, number base converter, colour space converters
• Generation — UUID/GUID (v1, v4, v5), password generator, QR code generator, cron expression builder
• Text & Code — Regex tester with match highlighting, string escape/unescape, text case converter, text diff
• Web utilities — URL parser, Unix file permissions calculator, Markdown previewer, IP subnet calculator
• Image utilities — colour picker from image, image to Base64, PNG to SVG, SVG to PNG

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How tools are built and verified

1. Requirement definition — I document what the tool should accept, what it should produce, and what edge cases it must handle (malformed input, empty input, large input, non-ASCII characters)
2. Implementation — Tools use established .NET libraries or browser-native APIs. JSON processing uses System.Text.Json. Hashing uses System.Security.Cryptography. Image processing uses the Canvas API. No crypto primitives written from scratch.
3. Testing against sample and edge-case input — Each tool is checked with representative sample inputs: minified and malformed JSON, test JWTs signed with known keys, tricky regex patterns, and timestamps in several formats
4. Content review — Educational content is drafted with AI assistance, then reviewed by the author and checked against the relevant RFC, standard or official documentation
5. Security review — Tools handling security-sensitive input (JWTs, passwords, hashes) include explicit usage warnings and known misuse patterns

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The technical architecture

DevToolsHub is built on ASP.NET Core 8 with Blazor Interactive Server and MudBlazor for components. The choice of Blazor Server was deliberate: it enables a reactive UI without shipping a WebAssembly payload, and keeps all tool logic on the server side of the circuit in a single C# codebase — the same language I work in all day.

Code editor panels — used in JSON Formatter, YAML Formatter, HTML Formatter, SQL Formatter, Regex Tester, and several other tools — are powered by Monaco Editor, the same editor that runs inside Visual Studio Code.

There is no database. Tool processing happens entirely in-session, in-memory, and is discarded when the Blazor circuit closes. The only persistent storage is localStorage for theme preferences and recently-used tools, which never leaves the browser.

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Privacy by design

The privacy model is an engineering constraint, not a legal afterthought. Every tool was designed under the assumption that the user might be pasting sensitive data: a JWT from a production system, a JSON response containing API keys, a password being evaluated for strength.

This means: tool inputs are not written to logs or a database, and analytics events do not include input content. To keep repeat requests fast, the API holds some results in server memory for up to five minutes. Google Analytics 4 is on by default (you can opt out), and anonymous performance monitoring (Azure Application Insights) is used to find slow pages and errors; both are described in the Privacy Policy. Even so, avoid pasting live production secrets into any online tool.

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The developer blog

The DevToolsHub developer blog is being rebuilt as a set of tested technical guides: each one explains a .NET topic and shows code and output that were actually run. Older articles that were not based on tested results have been removed.

Articles are published when there's something genuinely worth explaining — a topic that's consistently misunderstood, a common mistake that causes real bugs, or a concept that's poorly documented elsewhere. The goal is evergreen content that remains accurate and useful two years after it's published.

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Monetisation and sustainability

DevToolsHub is free to use and all tools will remain free. The site uses Google AdSense to display non-intrusive advertisements that cover hosting, infrastructure, and domain costs.

There are no paywalled tools, no premium tier, no email capture, and no dark patterns. If you find a tool useful, sharing it with a colleague is the best way to support the site.

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Get in touch

Found a bug? Have a tool request? Use the contact form or email [email protected] directly. I read the messages I receive and aim to respond to bug reports within a few days.

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