Developer tools that respect your data
Format JSON, decode JWTs, explain cron expressions, count AI tokens and estimate API cost — all instantly, all in your browser. No accounts, no usage caps, and your input never leaves your machine.
Every tool runs locally, in your browser
Nothing you paste is transmitted anywhere. There is no backend to send it to.
AI Token Counter & Cost Estimator
Count tokens and estimate API cost before you ship a prompt.
AIJSON Formatter & Validator
Pretty-print, minify and validate JSON with exact error positions.
DataJSON ⇄ YAML Converter
Convert between JSON and YAML in both directions.
DataBase64 Encoder & Decoder
Encode and decode Base64 and URL-encoded text, UTF-8 safe.
EncodingText Diff Checker
Compare two texts line by line and see exactly what changed.
TextCron Expression Generator & Explainer
Describe any cron expression in plain English and preview the next runs.
DevOpsRegex Tester
Test regular expressions live with match highlighting and capture groups.
TextJWT Decoder
Decode a JWT and inspect its header, claims and expiry.
SecuritySQL Formatter & Beautifier
Turn unreadable one-line SQL into clean, indented, reviewable code.
DataUUID & Hash Generator
Generate v4 UUIDs, hash text with MD5/SHA-1/SHA-256/SHA-512, and make passwords.
SecurityDeep dives written for practitioners
Long-form explanations of the things these tools touch — with the failure modes included, not just the happy path.
How AI Token Counting Works
A token is not a word, and the difference between the two is where most LLM cost estimates go wrong. Here is how tokenizers actually split your text.
LLM API Cost Compared
Published per-million-token prices are only half the equation. Tokenizer differences, caching, batching and reasoning tokens change the real number.
JWT Explained
A JWT is three Base64 segments and a signature. Understanding what the signature does — and does not — prevent is the whole game.
Prompt Engineering for Developers
Prompt engineering is mostly specification writing. Here is a structure that produces reliable output, and the failure patterns that break it.
Cron Expressions Explained
Cron is five fields and a set of rules most people learn by trial and error. Here is the whole thing, including the OR rule that causes real outages.
Regular Expressions: A Practical Guide
Most regex bugs come from one thing: not knowing that the engine backtracks. Understand that and the rest follows.
Built for the way you actually work
Nothing leaves your browser
Every tool is client-side JavaScript. Paste a production JWT, a customer payload or a proprietary prompt — it is processed in your tab and never transmitted. Verify it in the network tab, or just disconnect and keep using the tools.
No accounts, no caps
No signup wall, no "three conversions per day", no email harvest. Open the page, paste, get the result. Use it once or five hundred times.
Honest about its limits
Token counts are labelled as estimates, with instructions for getting an exact number. Pricing is dated and flagged. The JWT decoder refuses to pretend it can verify a signature. We tell you where the tools stop being reliable.
Bookmark it. Use it daily.
Ten tools, no accounts, no upload step, no usage caps. Add DevForge to your bookmarks bar and stop hunting for a tool every time you need one.
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