Developer tools built by a .NET engineer — including utilities you won't find anywhere else.

I'm Pankaj Kumar, a Senior Software Engineer who's been writing production C# since 2022 — most of my day is spent in ASP.NET Core, Blazor, and Entity Framework Core. I built DevToolsHub because the tools I kept reaching for were slow, covered in ads, or asked me to paste sensitive data into sites I had no visibility into. The .NET-specific tools below — EF Core migration analysis, LINQ-to-SQL translation, appsettings diffing — exist because I needed them myself and couldn't find them anywhere else.

No login required

No data stored

Works in your browser

Free forever

.NET-specific tools

Built from real day-to-day .NET work — the kind of tool you end up writing yourself if nobody else has, because generic converters don't cover it.

.NET Tools

appsettings.json Environment Diff

Diffs appsettings.Development.json against Production to catch the exact config-key mismatch that breaks logins after deploy.

Open tool

.NET Tools

Connection String Builder & Validator

Builds or validates SQL Server, PostgreSQL, MySQL, and Cosmos DB connection strings — flags a missing Encrypt=True or a plaintext password before it ships.

Open tool

.NET Tools

SQL Table to C# Entity Generator

Turns a CREATE TABLE script into a ready-to-use EF Core entity, with your choice of data annotations or Fluent API configuration.

Open tool

.NET Tools

JSON to C# Class/Record Generator

Generates strongly-typed C# classes or records straight from a JSON payload — nested objects and arrays included.

Open tool

.NET Tools

XML to C# Class Generator

Generates XmlSerializer-decorated C# classes from any XML — handles attributes, collections, and nested types.

Open tool

.NET Tools

LINQ to SQL Converter

Shows you the actual SQL Server or PostgreSQL your LINQ query would generate, before you find out the hard way in production.

Open tool

.NET Tools

Csproj Analyzer & Cleaner

Finds the duplicate PackageReferences and redundant SDK-default properties quietly bloating your .csproj.

Open tool

.NET Tools

EF Core Migration SQL Explainer

Reads a dotnet ef migrations script and flags every DROP COLUMN and DROP TABLE before you run it against a real database.

Open tool

.NET Tools

C# to JSON Sample Generator

Generates a realistic sample JSON payload straight from a C# class or record — no more hand-typing test fixtures.

Open tool

.NET Tools

ASP.NET Core Route Tester

Tests ASP.NET Core route templates and constraints against a real URL, showing exactly why a route did or didn't match.

Open tool

.NET Tools

NuGet Package Version Conflict Explainer

Paste NU1605/NU1107 error output and get the conflict chain explained with resolution snippets.

Open tool

.NET Tools

Dockerfile Generator for .NET

Generates a production-ready Dockerfile for ASP.NET Core apps with multi-stage build and non-root user by default.

Open tool

.NET Tools

Minimal API Endpoint Scaffolder

Scaffolds complete Minimal API endpoint groups with TypedResults, DTOs, and validation stubs from your entity fields.

Open tool

.NET Tools

C# ↔ VB.NET Converter

Converts between C# and VB.NET using Roslyn — handles records, pattern matching, async/await, and flags what needs manual review.

Open tool

From the blog

Practical guides on the formats and tools every developer works with.

17 Jul 2026 · 8 min read

Why Our Scheduled Jobs Ran at the Wrong Time After Deploying to Azure

Azure App Service runs in UTC. A cron expression written for 9 AM IST ran at 2:30 PM. Here is how to write timezone-correct cron schedules for Hangfire, Quartz.NET, and Azure Functions.

Read article

17 Jul 2026 · 16 min read

HTTP Status Codes: The Complete Developer Reference

Every IANA-registered HTTP status code, what it means, and how to return it correctly from ASP.NET Core with TypedResults, HttpStatusCode, and IActionResult.

Read article

15 Jul 2026 · 7 min read

Debugging a JWT That Validated Locally But Failed in Production

A JWT decoded fine and validated in Development but every request failed with SecurityTokenInvalidIssuerException in Production. Here is the exact ASP.NET Core JWT bearer mechanics behind it.

Read article

15 Jul 2026 · 7 min read

The EF Core Migration That Would Have Dropped a Production Column

A one-line C# property rename generated an EF Core migration that would have silently deleted a production column's data. Here is exactly why, and the fix.

Read article

14 Jul 2026 · 10 min read

The Regex That Worked in Production But Caused 100% CPU Usage Under Load

A template validator regex caused 90-second CPU spikes under specific user input. The cause was catastrophic backtracking from nested quantifiers, and the fix involved Regex timeouts and RegexOptions.NonBacktracking.

Read article

10 Jul 2026 · 9 min read

We Used MD5 for Our File Integrity Checks. Here's Why We Switched to SHA-256.

A security audit flagged MD5 checksums in our .NET file processing service. Here is exactly when MD5 is dangerous, when it is still acceptable, and the C# migration to SHA-256.

Read article

View all articles →

All tools

48 more tools, grouped by category. Every link below is a real page — expand a category or use the search box in the sidebar.

Formatters (7)

JSON Formatter Format and validate JSON with consistent indentation.

SQL Formatter Format SQL queries for better readability.

YAML Formatter Format and validate YAML with consistent indentation.

HTML Formatter Prettify and indent HTML markup for readability.

XML Formatter Format and validate XML with consistent indentation.

CSS Formatter Beautify and reformat minified or messy CSS stylesheets.

Markdown Preview Preview Markdown as clean rendered HTML.

JWT & Auth (4)

JWT Decoder Decode JWT header and payload data instantly.

JWT Generator Build and sign JWT tokens with HS256, HS384 or HS512.

JWT Secret Generator Generate cryptographically secure signing secrets for JWT.

Password Generator Generate strong passwords with configurable rules.

Encoding & Hashing (5)

Base64 Encoder / Decoder Encode or decode Base64 content quickly.

URL Encoder / Decoder Encode or decode URL-encoded strings instantly.

HTML Entity Encoder / Decoder Encode or decode HTML entities with a single click.

String Escape / Unescape Escape or unescape strings for JSON, HTML, URL, C#, Regex and XML.

Hash Generator Generate MD5, SHA1, SHA256 and SHA512 hashes.

Generators (7)

UUID Generator Generate one or more UUID values.

QR Code Generator Generate a QR code from any URL or text.

Barcode Generator Generate 1D barcodes in Code128, EAN-13, EAN-8, UPC-A and Code39 formats.

Lorem Ipsum Generator Generate placeholder lorem ipsum text for any layout.

Cron Expression Generator Build, explain, and compare cron expressions — includes a Hangfire vs Quartz.NET format comparison and next-run-time preview.

.gitignore Generator Generate .gitignore files for any language, framework or IDE.

Fake Data Generator Generate realistic mock JSON or CSV records for testing and prototyping.

Converters (13)

Timestamp Converter Convert Unix timestamps and UTC dates.

CSV ↔ JSON Converter Convert between CSV and JSON formats instantly.

Color Picker + Converter Convert HEX, RGB, and HSL values.

Color Picker from Image Extract dominant colors from any uploaded image as HEX and RGB swatches.

Number Base Converter Convert numbers between binary, octal, decimal and hex.

Image to Base64 Convert image data to Base64.

Base64 to Image Decode Base64 into image-ready data.

SVG to PNG Converter Convert SVG markup to a PNG image at any scale. Runs entirely in your browser.

PNG to SVG Converter Wrap a raster image (PNG, JPG, WebP) inside an SVG container for use in vector workflows.

Image to Text (OCR) Extract text from any image using Tesseract OCR — runs entirely in your browser.

JSON ↔ YAML Converter Convert between JSON and YAML formats instantly.

Timezone Converter Convert a date and time between any two timezones instantly.

Date Difference Calculator Calculate the exact difference between two dates in years, months, days, and more.

Text & Analysis (6)

Regex Tester Test patterns against sample input and inspect matches.

Text Compare Compare two text blocks and inspect their differences.

JSON Diff Tool Compare JSON documents and inspect changes.

JSON to TypeScript Generate TypeScript interfaces from any JSON payload instantly.

Word & Character Counter Count words, characters, lines and sentences.

Text Case Converter Convert text between camelCase, PascalCase, snake_case and kebab-case.

Web & Dev (6)

URL Parser Break a URL into scheme, host, path and query parameters.

Unix Permissions Calculator Convert between octal notation and symbolic permissions.

HTML Minifier Minify HTML output for leaner payloads.

CSS Minifier Minify CSS while preserving valid rules.

IP / CIDR Subnet Calculator Calculate network address, broadcast, host range and subnet mask from any CIDR block.

CSS Gradient Generator Generate CSS linear and radial gradients with a live preview and copy-ready CSS output.

About DevToolsHub

DevToolsHub is a free collection of browser-based developer utilities built for developers who want fast, no-fuss tools without signing up, installing software, or pasting sensitive data into unknown third-party services. Every tool on the site processes your input one of three ways: entirely in your browser, in-memory on the server for the duration of your active session, or via a dedicated API over HTTPS that discards it immediately after returning the result — nothing is logged, stored, or associated with your identity.

The site covers the tools developers reach for dozens of times a week: formatters for JSON, SQL, YAML, HTML, CSS, and XML; encoders and decoders for Base64, URLs, and HTML entities; generators for UUIDs, passwords, QR codes, cron expressions, and .gitignore files; converters for timestamps, timezones, number bases, CSV/JSON, JSON/YAML, and text case; date difference calculators; CSS gradient generators; and testing tools for regex patterns, text diffs, and JWT tokens. New tools are added regularly based on feedback from the developer community.

DevToolsHub is built with ASP.NET Core 8, Blazor Server, and MudBlazor, and hosted on Microsoft Azure. The site is designed to load fast, work on any screen size, and stay out of your way — no mandatory sign-ups, no upsell prompts, no dark patterns. The blog covers practical guides on the formats and protocols the tools work with: what Base64 actually is, how JWT tokens are structured, what makes a cron expression tick, and more.

DevToolsHub was built and is maintained by Pankaj Kumar, a software developer based in India. If you find a bug, want to request a tool, or have feedback, use the contact page or email [email protected].

Why DevToolsHub?

No login or account required for any tool
No data stored — inputs are processed and discarded
All 62 tools in one place, no switching between sites
Works on desktop, tablet, and mobile
Dark and light mode with accent colour choices
Completely free, no premium tier
New tools added based on community requests