Small tools that
stay on your machine.
Single-purpose utilities for the small jobs in a working day: format some JSON, decode a token, check a CIDR range. They run in your browser, so nothing you paste is sent anywhere. They're grouped by area below, or use the search to jump to one.
In daily use.
JSON Formatter
Format, beautify, validate. Handles streaming and large files.
Regex Tester
Live matches with group explanations.
DNS Lookup
Resolve A, AAAA, MX, TXT, NS, SOA, CAA: over Cloudflare DoH, in your browser.
Color Tools
Convert, blend, lighten, darken: every common operation.
Data.
Tools for inspecting, translating, and reconciling structured documents: JSON, YAML, SQL, and their kin. All run locally on whatever you paste in.
→ open the data drawerFormat, beautify, validate. Handles streaming and large files.
Strict syntax checker with line-precise error reporting.
Structural comparison with key-aware reordering.
Infer a Draft-07 schema from any JSON document.
Emit idiomatic Go struct definitions from a sample payload.
Query JSON with RFC-9535 syntax. Matches highlighted in place.
Lossless bidirectional conversion preserving key order.
Flatten and unflatten tabular data. Configurable delimiters.
Canonical formatting for twelve SQL dialects.
CommonMark + GFM. Sanitised by default.
Inline or side-by-side. Word- or character-level granularity.
Encode and decode, text or binary.
Reverse Base64 with UTF-8 or binary output.
Encode and decode URIs and query strings.
Developer.
Quick utilities for day-to-day development: IDs, hashes, claims, requests. All client-side; nothing leaves the tab.
→ open the developer drawerv1, v4, v7. Bulk mode. Copy or download.
Live matches with group explanations.
Sign, decode, and inspect header, claims, and signature.
Symbolic ↔ octal with common-case presets and special bits.
Epoch ↔ ISO-8601 ↔ human, in any timezone.
Compose and preview curl requests with full option coverage.
Side-by-side LCS diff, line/word/char granularity.
Network.
Probe the network the way an operator would. DNS, IP ranges, HTTP, WebSockets: visible, not mysterious.
→ open the network drawerResolve A, AAAA, MX, TXT, NS, SOA, CAA: over Cloudflare DoH, in your browser.
Network, broadcast, mask, and host count. Subnetting at a glance.
Classify any IPv4 or IPv6 address: RFC 1918 private, CGNAT, link-local, multicast.
Full status-code reference with examples.
Open a socket, send frames, read back the transcript.
Design.
Colour, type, and CSS: for engineers who design and designers who ship. Tuned for living design systems.
→ open the design drawerConvert, blend, lighten, darken: every common operation.
WCAG AA/AAA scores for text and large text.
Tonal scales, complementary sets, gradients, accessible pairings.
Modular scales: minor-third through golden.
4pt / 8pt grid generator with rem and px output.
Cubic-bezier playground with motion preview.
px ↔ rem ↔ em ↔ % at any base font size.
Per-corner border-radius generator with CSS + Tailwind output.
Multi-layer box-shadow generator with presets and live preview.
Kubernetes.
Targeted utilities for Kubernetes authoring: probes, resources, rollouts. Practitioner-grade.
→ open the kubernetes drawerSecurity.
Fundamentals for credentials and secrets: generated locally, never phoned home.
→ open the security drawerPush and read,
across the hall.
Bench tools are the small utilities. The simulators are where you push systems around, and the guides explain how each piece works underneath.