Developer Tool Guides & Tutorials - Page 2
Step-by-step guides for the 64 free online tools on dsjson.com: JSON formatting, encoding, hashing, image and PDF handling, with practical examples and troubleshooting.
30 guides in total · page 2 of 3
Why WebSocket Will Not Connect: Five Causes, In Order
Connection failures come down to five things - mixed content, Origin mismatch, wrong path, a proxy that drops Upgrade, or an untrusted certificate.
Generate API Types: JSON to TypeScript and SQL to Entities
Turn API responses into TypeScript types and CREATE TABLE statements into Java or C# entities, then unify naming. Includes type mapping and nullable pitfalls.
AES or RSA? Symmetric, Asymmetric and What Morse Code Is Not
AES is fast and symmetric, RSA is slow and asymmetric. Learn which to use, why keys and IVs must never repeat, and why Morse code is only encoding.
Chinese ID Card Number: Checksum, Region and Privacy Rules
What the 18 digits of a Chinese ID number encode, how the weighted mod-11 checksum works, how 15-digit numbers upgrade to 18, and how to handle them safely.
How to Watermark Images and Build GIFs: Frames, Ghosting, Size
Learn how watermark opacity, position and tiling trade protection against looks, why extracted GIF frames ghost, and how to cut an animated GIF below 5 MB.
Why Won't a Website Load? Diagnose IP, DNS, Port and Status Code
Diagnose a site that will not load in four layers: IP, DNS, port, HTTP status. Each step has a judgement rule and a cause table, plus WebSocket testing.
Binary, Hex and Full-Width Characters: A Practical Guide
Convert between binary, octal, hex and decimal, and find the full-width characters that break password checks and text search.
Run Code Online: Sandbox Limits for Python, JS, Java, Go, C++
Run code online to check syntax, test a small algorithm or share a reproducible snippet. Here are the sandbox limits, language gotchas and what never to paste.
How to Merge, Split and Convert Images to PDF Without Uploading
What happens when you merge A4 and Letter pages, how to fill page ranges, how DPI drives image-to-PDF quality, and why none of these files leave your browser.
Website Pre-Launch Checklist: Domain, robots.txt and Meta Tags
Four pre-launch checks: domain expiry, whether robots.txt blocks your own site, how the live page renders, and the meta tags search engines read.
Clean a Long List: Deduplicate, Sort and Reverse Text Lines
A practical guide to cleaning lists of hundreds of lines: what dedup does with case and trailing spaces, why 10 sorts before 9, and which reverse mode to pick.
How to Encode and Decode Base64 (and Fix Mojibake)
Decode Base64 without the usual traps: why output grows about 33%, when URL-safe Base64 is mandatory, how to read a JWT payload, and how to fix garbled text.