70 tools · 7 categories
Every tool
in the toolkit.
Pick a category below, or use the search. Nothing here needs an account and nothing is sent to a server you cannot see.
14 tools
Data.
Tools for inspecting, translating, and reconciling structured documents — JSON, YAML, SQL, and their kin. All run locally on whatever you paste in.
JSON Formatter Featured
Format, beautify, validate. Handles streaming and large files.
JSON Validator
Strict syntax checker with line-precise error reporting.
JSON Diff
Structural comparison with key-aware reordering.
JSON Schema Generator
Infer a Draft-07 schema from any JSON document.
JSON to Go
Emit idiomatic Go struct definitions from a sample payload.
JSONPath Extractor
Query JSON with RFC-9535 syntax. Matches highlighted in place.
YAML ↔ JSON
Lossless bidirectional conversion preserving key order.
CSV ↔ JSON
Flatten and unflatten tabular data. Configurable delimiters.
SQL Formatter
Canonical formatting for twelve SQL dialects.
Markdown ↔ HTML
CommonMark + GFM. Sanitised by default.
Text Diff Featured
Inline or side-by-side. Word- or character-level granularity.
Base64 Encoder Featured
Encode and decode, text or binary.
Base64 Decoder
Reverse Base64 with UTF-8 or binary output.
URL Encoder
Encode and decode URIs and query strings.
8 tools
Developer.
Quick utilities for day-to-day development — IDs, hashes, claims, requests. All client-side; nothing leaves the tab.
UUID Generator Featured
v1, v4, v7. Bulk mode. Copy or download.
Regex Tester Featured
Live matches with group explanations.
JWT Encoder
Sign, decode, and inspect header, claims, and signature.
Chmod Calculator
Symbolic ↔ octal, with common-case presets.
Timestamp Converter
Epoch ↔ ISO-8601 ↔ human, in any timezone.
curl Builder
Compose and preview curl requests with full option coverage.
Mock API Dashboard
Spin up disposable endpoints for integration work.
Git Diff Parser
Render unified diffs with syntax colouring.
3 tools
Network.
Probe the network the way an operator would. DNS, IP ranges, HTTP, WebSockets — visible, not mysterious.
8 tools
Design.
Colour, type, and CSS — for engineers who design and designers who ship. Tuned for living design systems.
Color Picker
HSL, RGB, HEX, OKLCH. Copy any format in a click.
Color Tools Featured
Convert, blend, lighten, darken — every common operation.
Contrast Checker
WCAG AA/AAA scores for text and large text.
Palette Generator
Tonal scales, complementary sets, accessible pairings.
Gradient Generator
Linear, radial, conic — copyable CSS output.
Box Shadow
Layer and composite shadows. Realistic elevation presets.
Border Radius
Independent corner control with live CSS.
Typography Scale
Modular scales — minor-third through golden.
2 tools
Kubernetes.
Targeted utilities for Kubernetes authoring — probes, resources, rollouts. Practitioner-grade.
1 tools
Security.
Fundamentals for credentials and secrets — generated locally, never phoned home.
34 tools
Simulators.
Interactive visualisations for learning distributed systems, algorithms, and data structures. Nothing beats moving the parts yourself.
CAP Theorem Featured
Pick two. Toggle the partition. Watch the third guarantee fail.
Consistent Hashing
Add, remove, and move nodes around the ring.
Database Sharding
Range, hash, and directory strategies compared.
Read/Write Quorum
Tune N, R, W — watch reads and writes succeed or stall.
Isolation Levels
Dirty reads, non-repeatable reads, phantoms — side-by-side.
Rate Limiter Featured
Token bucket, leaky bucket, fixed and sliding windows.
Circuit Breaker
State-machine resilience pattern, with failure playback.
Retry Strategy
Exponential, jittered, decorrelated — load-tested.
Load Balancer
Round-robin, least-conn, hashing, p2c — under real load.
Cache Eviction
LRU, LFU, ARC, TinyLFU compared in real time.
LRU Cache
Watch the list mutate as you read and write.
Chaos Playground
Inject latency, packet loss, and node failure at will.
TCP Handshake
Three-way and four-way, with sequence numbers.
TCP Congestion
Slow start, congestion avoidance, fast recovery.
HTTP Flow
Request lifecycle across client, proxy, origin.
HTTP/2 Streams
Multiplexed frames, dependencies, head-of-line blocking.
gRPC vs REST
Side-by-side wire format, streaming, error model.
JSON vs Protobuf
Size, parse cost, schema evolution.
JWT Lifecycle
Issue, verify, rotate, revoke — the full loop.
K8s Rollout
RollingUpdate, surge, unavailable — live deployment.
Pod Eviction
PDBs, node pressure, preemption — playable.
Goroutine Scheduler
GMP model: work stealing, netpoll, preemption.
Storage Engine
LSM and B-tree read/write paths side by side.
B-Tree
Insert, split, rebalance — node by node.
Trie / Autocomplete
Prefix tree walk-through with live lookup.
Bloom Filter
Tune bits and hashes; watch false-positive rate.
Linked List
Singly, doubly, circular — pointers annotated.
Queue & Stack
FIFO, LIFO, priority, deque — visualised.
Sorting Visualiser
Bubble, quick, merge, heap — comparison counts visible.
Binary Search
Leftmost, rightmost, insertion point patterns.
Dijkstra Pathfinding
Shortest path on a grid with weighted obstacles.
Algorithm Visualizer
Explore common algorithms step by step.
Decision Tree
Grow, split, prune — classification made visible.
Vector Embedding
Cosine similarity, ANN search, index tradeoffs.