⚡ 5 Tools · Blog · 100% Free · No Signup

Developer Tools
Built for Speed

Format JSON, beautify SQL, test APIs, decode JWTs and convert Base64 — all in one place.

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JSON Formatter

Format, validate and minify JSON with error highlighting.

format · validate · minify
⊞

SQL Formatter

Beautify SQL queries with indentation. MySQL, PostgreSQL and more.

mysql · postgres · sqlite
↗

API Tester

Send HTTP requests and inspect responses. GET, POST, PUT, DELETE.

GET · POST · REST
🔑

JWT Decoder

Decode JWT tokens and inspect header, payload and expiry claims.

header · payload · claims
⇄

Base64 Converter

Encode and decode Base64 strings. Standard and URL-safe support.

encode · decode · url-safe
📝

Developer Blog

Guides on JWT, SQL JOINs, Base64, JSON, REST APIs and more.

guides · tutorials
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Free Online Developer Tools — No Signup Required

DevTools Hub provides fast, browser-based utilities for everyday dev tasks. All processing is server-side — no client-side code to download or trust.

Why DevTools Hub?

No paywalls, no account, no bloated interface. Just paste, tap, done. Works perfectly on desktop and mobile.

▶ Is everything completely free?
Yes — all tools and blog content are free forever. No usage limits, no premium tier.
▶ Is my data secure?
Inputs are processed server-side and never stored. JWT tokens are decoded without signature verification and your data is never retained.

JSON Formatter & Validator

Format, validate and minify JSON instantly.

Input JSON
Output
Processing...
Output will appear here...
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JSON Formatter Online — Free JSON Beautifier & Validator

Instantly format, validate and minify JSON. Supports nested objects, arrays, unicode, and shows precise error locations for invalid JSON.

▶ Why is my JSON invalid?
Common mistakes: trailing commas, single quotes, unquoted keys, or comments — JSON does not support comments. Our validator shows the exact line and column.
▶ Format vs Minify?
Format adds indentation for readability. Minify strips whitespace for smaller payloads — typically 20–40% smaller.

SQL Formatter & Beautifier

Format messy SQL queries with proper indentation.

Input SQL
Formatted SQL
Formatting...
Formatted SQL will appear here...
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SQL Formatter Online — Beautify SQL Queries Instantly

Format complex SQL with proper indentation and consistent keyword casing. Handles JOINs, CTEs, subqueries and GROUP BY.

▶ Does it support CTEs?
Yes — WITH clauses, subqueries, OVER/PARTITION BY, and most standard SQL constructs are handled correctly.

REST API Tester

Send HTTP requests and inspect responses. Like Postman, in your browser.

Sending request...
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API Tester Online — Test REST APIs Without Postman

Send GET, POST, PUT, PATCH, DELETE requests with custom headers and body. View status codes, timing, response headers and body.

▶ Does it support auth headers?
Yes — add an Authorization header manually. For example: key Authorization, value Bearer your-token.
▶ Can I test private or localhost APIs?
Requests are proxied through our server. Private IPs and localhost are blocked for security.

JWT Decoder & Inspector

Decode any JWT token to inspect header, payload and expiry.

JWT Token
Decoding...
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JWT Decoder Online — Decode & Inspect JSON Web Tokens

Paste any JWT to see its header, payload claims, algorithm, expiry and issued-at time. Works with HS256, RS256, ES256 and all standard algorithms.

▶ Is it safe to paste my JWT?
Never paste production JWTs with sensitive data into online tools. Use test or sample tokens for debugging.
▶ Does this verify the signature?
No — this only decodes the header and payload. Signature verification requires your secret or public key and must be done in your application code.

Base64 Encoder & Decoder

Convert text to Base64 and back — standard or URL-safe.

Plain Text
Base64 Output
Converting...
Output will appear here...
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Base64 Encoder Decoder Online — Free Converter

Encode strings to Base64 or decode Base64 to text. Supports standard and URL-safe (RFC 4648). Used in JWTs, data URIs, and HTTP Basic Auth.

▶ Standard vs URL-safe Base64?
Standard uses +, / which have special meaning in URLs. URL-safe replaces them with -, _ and is used in JWTs and browser cookies.
▶ Why does Base64 end with ==?
Base64 encodes 3 bytes to 4 chars. If input is not divisible by 3, = padding is added to complete the last block.

Developer Blog

Guides, tutorials and explainers for backend developers.

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