JWT Decoder
Decode a JSON Web Token to read its header and payload.
Open toolFree tools
Developer tools
Small, fast utilities that run entirely in your browser — nothing is uploaded to a server. Built by Aman Kumar Singh alongside the engineering blog.
UUID Generator
Generate random version 4 UUIDs in your browser.
Open toolBase64 Encoder / Decoder
Encode text to Base64 or decode Base64 back to text.
Open toolJSON Formatter & Validator
Pretty-print, minify, and validate JSON.
Open toolCron Expression Explainer
Translate a cron schedule into plain English.
Open toolUnix Timestamp Converter
Convert between Unix epoch time and human dates.
Open toolSlug Generator
Turn any title into a clean, URL-safe slug.
Open toolURL Encoder / Decoder
Percent-encode text for URLs, or decode it back.
Open toolPassword Generator
Generate strong random passwords in your browser.
Open toolHash Generator
Compute SHA-1, SHA-256, SHA-384, and SHA-512 hashes.
Open toolRegex Tester
Test a regular expression against text and see live matches.
Open toolSQL Formatter
Format and beautify SQL queries across major dialects.
Open toolMarkdown Preview
Write Markdown and see it rendered live, side by side.
Open toolRedis Memory Calculator
Estimate how much RAM your Redis dataset will use.
Open toolCache TTL Calculator
Convert a cache duration into seconds and ready-to-use headers.
Open toolAPI Latency Estimator
Estimate endpoint latency from its downstream calls.
Open toolAWS Pricing Estimator
Estimate a monthly AWS bill from editable line items.
Open toolSystem Design Capacity Estimator
Turn users into QPS, storage, and bandwidth for capacity planning.
Open toolPostgres Connection Pool Sizer
Find the right database pool size and max_connections.
Open toolSLA Uptime Calculator
Convert an availability target into allowed downtime.
Open toolRate Limiter Designer
Turn a rate limit into token-bucket parameters.
Open toolBig-O Complexity Calculator
See the operation count for each complexity class at your input size.
Open tool