Development
Browse the complete ASCII character table (0–127) with decimal, hex, octal, binary, HTML entity, and control character names; filter by code or name
ascii-tableDevelopment
Upload any binary file and inspect it as a classic hex dump with offset, hex bytes, and ASCII columns (read-only)
hex-editorDevelopment
Complete HTTP status code reference (1xx–5xx) with semantics, typical scenarios, and retry advice in a filterable comparison table
http-status-referenceDevelopment
Calculate CSS selector specificity scores, compare multiple selectors, and get suggestions for avoiding cascade conflicts
css-selector-specificity-calculatorDeveloper Tools
Visualize JSON or JSONL as an expandable tree and copy JSONPath expressions for every node
json-path-visualizerDevelopment
Compare two API response payloads, highlight field-level diffs, and classify likely functional changes versus harmless runtime drift
api-response-diff-semantic-analyzerDevelopment
Generate pure CSS masonry-style layouts with responsive breakpoints, configurable gaps, and optional full-width skip selectors
css-masonry-layout-generatorDevelopment
Mutate OpenAPI request fields into semantically risky variants and optionally send them to a real backend to check defensive validation coverage
api-contract-mutation-testerDevelopment
Validate a real API response JSON against the response schema declared in an OpenAPI 3.x specification
api-response-contract-validatorDevelopment
Compare two OpenAPI 3.x schemas, identify breaking changes, grade client impact, and suggest migration or compatibility strategies
api-breaking-changes-detector-migration-plannerDevelopment
Simulate the next runs of one or two 5-part cron expressions, highlight overlaps, and warn about overly dense schedules
cron-job-simulatorDevelopment
Generate boundary-value test cases from an OpenAPI 3.x document and optionally send them to a real backend to spot contract mismatches
api-contract-stress-tester