Blog
Engineering Behind DataFormatter
Source-accurate write-ups of how the DataFormatter developer tools actually work under the hood — data formats, API contracts, debugging, integer math, checksums and in-browser compilation. Every claim is verified against the implementation that ships on this site.
- Data FormatsAug 4, 20263 min read
How the JSON Formatter Validates and Pretty-Prints JSON
A JSON formatter is really two passes: a strict parse that rejects invalid JSON, then a reserialization with two-space indentation. Here's exactly what happens between paste and output.
- Data FormatsAug 6, 20262 min read
How JSON Diff Finds Added and Removed Fields
Diffs between two JSON documents are produced by a recursive structural walk that compares objects by key set, arrays by position, and every value by its canonical serialization.
- Algorithms & Computer ScienceJul 21, 20263 min read
Signed vs Unsigned Integers: Ranges, Overflow and When to Use Each
An N-bit integer stores 2^N distinct patterns. Whether those patterns stand for 0..2^N−1 (unsigned) or −2^(N−1)..2^(N−1)−1 (signed) changes the range, the largest value and how overflow behaves.
- Algorithms & Computer ScienceJul 23, 20263 min read
Two's Complement Explained: How Signed Integers Are Stored in Binary
Two's complement is the storage convention behind every signed integer on modern hardware: a negative value is the bitwise inversion of its positive magnitude plus one, and the high bit acts as the sign.
- Algorithms & Computer ScienceJul 28, 20263 min read
CRC-32 Explained: The Checksum Algorithm Behind Data Integrity
CRC-32 is a 32-bit error-detection checksum built from binary polynomial division. Real implementations skip the math per bit and use a 256-entry lookup table driven by the reflected polynomial 0xEDB88320.
- API EngineeringAug 12, 20263 min read
What Makes an API Change Breaking? A Field-by-Field Guide
An API change is breaking when existing clients can no longer parse, validate or safely navigate the response. Some breaks are obvious; a few are genuinely surprising — and a good detector gets both right.
- DebuggingAug 24, 20263 min read
How to Read a Stack Trace: Exception Types, Frames and Call Chains
A stack trace is the call path at the moment of failure: the exception type and message up top, then one frame per function, each with a file and line. Read it top-down, then jump to the first frame in your code.
- DebuggingAug 26, 20263 min read
HTTP Headers Every Developer Should Know
A response headers block is a diagnosis in plain text: caching freshness, CORS policy, session protections and security posture. Knowing the handful that matter turns an opaque wall into a readable story.
- API EngineeringAug 18, 20263 min read
OpenAPI 3.0 vs 3.1: What Changed and Why It Matters
OpenAPI 3.1 adopted JSON Schema 2020-12, which replaced nullable with type arrays, made exclusive bounds numeric and added webhooks. Both 3.0 and 3.1 documents are parsed by the same workbench.
- Browser EngineeringAug 30, 20264 min read
How Running Code in the Browser Actually Works
An in-browser code runner never touches your server: each execution gets its own Web Worker, the main thread is protected by a hard timeout, and outputs are captured from a patched console before the worker is torn down.
- API EngineeringSep 15, 20264 min read
How to Decode a JWT: Header, Payload and Claims Explained
A JWT looks like eyJhbGciOi… but it's just three base64url parts: header, payload and signature. Decoding shows you the algorithm and the claims — decoding is not the same as verifying.
- Data FormatsSep 24, 20263 min read
Base64 vs Base64URL: What's the Difference and When to Use Each
Base64 and Base64URL look almost identical but differ in two characters and padding rules. The wrong variant breaks URLs, file names and JWTs — here's when each is safe and how to pick.
- DebuggingSep 24, 20264 min read
Unexpected Token in JSON: What It Means and How to Fix It
Every 'Unexpected token' message names the character that stopped parsing. Learn what Chrome, Firefox and Safari each say, why trailing commas and HTML pages cause it, and how to find the fix fast.
- API EngineeringSep 24, 20263 min read
How to Test an API Without Postman
You don't need a heavyweight client to test an API. Build a request in-browser, inspect the response, import an existing curl command, and generate code — all locally, with zero installation.
- API EngineeringSep 24, 20263 min read
How to Convert cURL Commands to JavaScript, Python & Go
curl has a different spelling of the same request for every language you target. An importer reads the flags once and emits runnable fetch, axios, Python, Java or Go code — so you stop translating by hand.
- DebuggingSep 24, 20263 min read
How to Debug CORS Errors in Your Browser
'Blocked by CORS policy' looks like your request failed — but it was probably fine. Learn what the browser checks before code runs, how to read the error, and how to confirm a fix without guessing.
- API EngineeringSep 24, 20263 min read
How to Inspect an OpenAPI Specification
A 3.x OpenAPI file is a dense JSON or YAML contract. Learn where to look — info, servers, paths, components — and how a workbench turns the document into live requests and generated code.
- DebuggingSep 24, 20263 min read
How to Debug a JSON API Response
A response that won't parse usually has one of a handful of causes. Read it in order: status, headers, body text, then validation — each step narrows the bug before your editor does anything.