Practical Browser Tools for Debugging Real Developer Work
Format API payloads, decode suspicious strings, inspect broken URLs, convert log timestamps, generate test identifiers, and prepare documentation without creating an account or uploading private data.
JSON Formatter
API & JSON
Format, validate, and inspect API responses, webhook payloads, and config snippets with clear parse errors.
Word Count
Writing & Documentation
Check words, characters, sentences, and paragraphs while editing docs, release notes, prompts, and UI copy.
Base64 Encoder/Decoder
Encoding & URLs
Decode JWT sections, Basic Auth values, Kubernetes secrets, and Base64URL strings without sending data to a server.
URL Encoder/Decoder
Encoding & URLs
Encode query values, decode broken callback URLs, and inspect percent-encoded parameters from logs and redirects.
Unix Timestamp Converter
Time & IDs
Convert epoch seconds or milliseconds from logs, JWT claims, cache headers, and webhook events into readable time.
UUID Generator
Time & IDs
Generate UUID v4 values for test fixtures, seed data, correlation IDs, local records, and debugging examples.
Case Converter
Writing & Documentation
Convert API fields, database columns, filenames, headings, and labels between common naming conventions.
Markdown Preview
Writing & Documentation
Preview READMEs, pull request notes, docs pages, and release notes before broken Markdown reaches production.
Debugging Categories
The site is organized around common backend, API, and AI-agent development chores: payload inspection, encoding issues, time and ID handling, and technical writing.
API & JSON
Validate API responses, inspect webhook payloads, and understand why parsers reject malformed JSON.
Encoding & URLs
Decode Base64, fix percent-encoded query strings, and debug redirect, callback, and header values.
Time & IDs
Convert epoch timestamps, compare UTC and local time, and generate safe identifiers for test data.
Writing & Documentation
Prepare readable docs, release notes, prompts, pull request text, and API field names.
What This Site Is For
Songtov Utility is built for developers who need to answer small but blocking questions quickly: Is this webhook payload valid JSON? Why did this OAuth redirect split into the wrong parameters? Is this JWT timestamp seconds or milliseconds? Can I decode this Base64 value without pasting it into a random server?
Tools run in the browser and guides explain the failure modes behind them. The goal is a practical reference site for backend, API, automation, and AI-agent development work.
Maintained by Chiho Song, a backend developer now building AI agents, the site focuses on debugging tasks that show up in real engineering work: payload validation, encoding mismatches, timestamp confusion, identifier choices, and documentation cleanup.
Recommended Debugging Guides
Start here if you are debugging an API response, encoded value, timestamp, token, or generated identifier.
How to Format and Validate JSON: A Complete Guide
Learn everything about JSON formatting and validation — from the basics of JSON syntax to common errors and how to fix them.
Encoding & URLsURL Encoding Guide: Percent-Encoding, Query Strings, and Common Bugs
Learn how URL encoding works, when to use encodeURI vs encodeURIComponent, why spaces become %20 or +, and how to debug broken query strings.
Time & IDsUnix Timestamps Explained: Seconds, Milliseconds, UTC, and Timezones
A practical guide to Unix epoch time for developers, including seconds vs milliseconds, timezone display, JWT dates, database fields, and log debugging.
Encoding & URLsBase64 Encoding Explained: How It Works and When to Use It
A practical guide to Base64 encoding — how the algorithm works, why it exists, when you should and should not use it, and how to avoid the most common pitfalls.
Time & IDsUUID v4 Guide: When Random Identifiers Are the Right Choice
Understand how UUID v4 identifiers work, when to use them, when not to, and how they compare with sequential IDs, slugs, and time-sortable IDs.
Latest from the Blog
View all posts →URL Encoding Guide: Percent-Encoding, Query Strings, and Common Bugs
Learn how URL encoding works, when to use encodeURI vs encodeURIComponent, why spaces become %20 or +, and how to debug broken query strings.
Time & IDsUnix Timestamps Explained: Seconds, Milliseconds, UTC, and Timezones
A practical guide to Unix epoch time for developers, including seconds vs milliseconds, timezone display, JWT dates, database fields, and log debugging.
Time & IDsUUID v4 Guide: When Random Identifiers Are the Right Choice
Understand how UUID v4 identifiers work, when to use them, when not to, and how they compare with sequential IDs, slugs, and time-sortable IDs.
Missing a Debugging Tool?
Send a concrete bug, payload shape, log snippet pattern, or workflow gap. New tools are chosen when they solve a repeatable development problem and can be explained clearly.