Payloads, notes, and state stay local whenever that makes sense. Less friction and real privacy.
Local lab
Open a random one Workbench
33 toolsA clear catalog for validating, generating, inspecting, and testing from the browser.
Audio Lab
Tuning, reference tones and quick analysis for testing speakers, DACs and signal chains from the browser.
- Tone GeneratorConfigurable oscillator for testing speakers, DACs, filters and audio signal chains.Local only
- Guitar TunerLocal chromatic tuner with pitch detection, nearest note and cents offset.Local only
- Spectrum AnalyzerRealtime microphone FFT to inspect frequency energy from the browser.Local only
- MetronomeConfigurable musical click with tempo, beats and subdivisions for practice or timing tests.Local only
- Beat CounterEstimate BPM by tapping the pulse with clicks or the spacebar.Local only
- Delay CalculatorConvert BPM to musical delay times and milliseconds to acoustic distance.Local only
Network Lab
DNS, certificates, subnets, domains and connectivity checks from one clear surface.
- DNS InspectorQuery live DNS records, including MX, TXT, NS, A, and AAAA, without leaving the workbench.Makes network calls
- IPv4/Subnet CalculatorCalculate network, broadcast, mask, wildcard and usable hosts from CIDR.Local only
- WHOIS / RDAPQuery public domain registration data with RDAP, the modern WHOIS replacement.Makes network calls
- Certificate ExpiryInspect live TLS certificates, issuer details, and remaining validity before they become an outage.Makes network calls
- Site CheckerMonitor URLs from the browser only, with local checks and desktop notifications.Makes network calls
- URL Parser & BuilderParse URLs, inspect query params and build modified URLs — all in your browser.Local only
Validation
Decode, inspect, and verify payloads, auth artifacts, DNS records, or TLS state before they reach production.
- Payload LabFormat, validate, and share JSON payloads without leaving the browser.Local only
- Type CheckerValidate in the browser whether a JSON payload is assignable to a root TypeScript type.Local only
- JWT PlaygroundInspect JWT headers, payloads, and expiration locally without sending the token anywhere.Local only
- Hash & DigestGenerate SHA-1/256/384/512 digests (hex and base64) entirely in your browser.Local only
Generation
Produce useful strings, snippets, and other quick artifacts without leaving the browser.
- Object to TypesGenerate TypeScript interfaces and aliases directly from a real JSON object.Local only
- Random String GeneratorGenerate quick strings for secrets, IDs, demos, or fixtures in one place.Local only
- Encoder / DecoderBase64, base64url, hex and URL encode/decode (UTF-8) in your browser.Local only
- UUID / ULIDGenerate UUID v4 and ULID identifiers in batches, in your browser.Local only
- Mermaid DiagramsEdit and render Mermaid diagrams (flowchart, sequence, UML…) in your browser.Local only
- Snippets ShelfStore quick notes, recipes, and frequent fragments locally.Local only
- Markdown NotesLocal-first markdown notes with a live preview, in your browser.Local only
- Pattern LessonsInteractive modern-pattern lessons with editable code and a sandboxed runner.Local only
- Color ToolsConvert HEX, RGB, HSL; pick colors and inspect WCAG contrast ratios — all in your browser.Local only
- Timestamp ConverterConvert Unix timestamps and date strings to ISO, UTC, relative and more formats.Local only
- JSON Schema GeneratorInfer a JSON Schema from any JSON sample with format detection and required-field analysis.Local only
- Image to Base64Convert images to data URIs, base64, CSS snippets or HTML img tags.Local only
Testing
Compare objects, inspect differences, and jump into embedded validation flows.
- Object ComparatorCompare two JSON objects and surface structural differences in seconds.Local only
- Regex TesterTest regex patterns against multiline input with live highlight and group capture.Local only
- Text DiffCompare two texts line by line (LCS) entirely in your browser.Local only
- Cron ExpressionParse cron expressions and preview next run times with a field breakdown — no server needed.Local only
- Number Base ConverterConvert between decimal, hexadecimal, binary and octal with a bit-field visualizer.Local only
What this surface prioritizes
Clarity, contrast, and fast response before density.
When a workflow really matters, you can share it by URL instead of explaining ten manual steps.
It is not trying to look like a demo. It is trying to solve real work with as little friction as possible.