Tool ·
Step through concurrent programs one operation at a time, rewind, and try other interleavings: Go goroutines, channels, select, WaitGroup, Mutex and context (with a race detector, deadlocks and leaks), async Rust futures on a tokio-like executor, Java virtual threads on carriers with pinning, executors and CompletableFuture, and the JavaScript event loop — plus a runner that shows the real order of your own JS snippet.
Tool ·
Open a CPU, heap or lock profile — Go pprof, collapsed stacks from async-profiler, perf or cargo flamegraph, JDK Flight Recorder, a Node/Chrome .cpuprofile, speedscope or perf script — and read it as a flame graph or icicle with search, a top table, callers and callees, and a red/blue differential against a baseline, all in the browser.
Tool ·
Paste JSON samples (or a JSON Schema) and get TypeScript, Zod, Java records with Jackson (or Lombok classes), Kotlin, Go structs, Rust serde, Python pydantic or dataclasses, protobuf, or JSON Schema — merging samples to find optional fields, nulls, unions, enums, dates, UUIDs, maps and tagged unions.
Tool ·
How a Java process fills a container's memory limit — heap, metaspace, code cache, thread stacks, direct buffers, GC structures and native memory — with the heap the JVM picks by itself on JDK 17, 21, 25 and 27, the flags that fit, OOMKilled versus OutOfMemoryError, and NMT output to fill it in.
Tool ·
Read a JVM GC log — unified -Xlog:gc* for G1, ZGC (generational or not), Shenandoah, Parallel and Serial, or a JDK 8 PrintGCDetails log — and get a pause timeline, heap before and after, allocation and promotion rates, pause percentiles, throughput, full GCs and failures flagged, and tuning hints in plain words.
Tool ·
Drop a .class or .jar and read it like javap -v — class version, constant pool, fields, methods with full bytecode, every attribute — plus the JAR's manifest, module-info, multi-release versions, Spring Boot nested jars and duplicate classes.
Tool ·
Paste jstack, jcmd Thread.print, kill -3 or Thread.dump_to_file (text or JSON, with virtual threads) output: threads grouped by state and identical stack, deadlocks and a lock graph, thread pools, hot frames, CPU per thread, and a comparison of dumps taken seconds apart to find stuck threads.
Tool ·
Paste or drop logs (large files are streamed) — nginx/Apache, JSON lines, logfmt, syslog RFC 3164/5424, journald, Java with multi-line stack traces, Go zap/slog, Kubernetes CRI, CloudWatch — or write a grok pattern with the standard Logstash library; get field statistics, a zoomable time histogram, filter expressions, message templates (Drain), CSV/JSONL export, and the table in DuckDB lab or the data wrangler.
Tool ·
Paste POMs (with their parents and BOMs) and get the effective POM with where every value came from, profiles you can switch, BOM import order, the phases and plugin goals a command like mvn clean verify runs, and lints. Read build.gradle(.kts) with its version catalog and see which classpaths each dependency lands on. Convert POM ↔ Gradle and Groovy ↔ Kotlin DSL, and compare Maven and Gradle version ordering and conflict rules.
Tool ·
Paste a Go struct, Rust struct or enum, C struct or Java class and see every byte — fields, padding, object headers, enum tags and niches — on 64-bit and 32-bit targets, with Go's fieldalignment reordering, rustc's own field order, HotSpot's field packing, and a gallery of runtime internals (slice and interface headers, Vec, Box, Rc, fat pointers, String, HashMap.Node).
Tool ·
Paste Spring Boot Actuator output and read it: why each auto-configuration did or didn't apply, the bean dependency graph, which property source wins for every key, bound @ConfigurationProperties, the endpoint table, metrics and health. Plus a properties ↔ YAML converter with profiles, a checker for common keys, and every relaxed-binding form of a property name.
Article ·
How I built AOEE, an in-memory relationship cache for social-graph queries: posting lists borrowed from search engines, four adaptive encodings, set maths instead of joins, and friend-of-friend suggestions with a budget.
Tool ·
Write and run code in 29 languages — JavaScript, TypeScript, Python, Java, Kotlin, C, C++, Rust, Go, R, PHP, Perl, Ruby, Lua, OCaml, Fortran, Clojure, Scheme, Prolog, BQN, Forth, BASIC, SQLite, DuckDB, HTML, p5.js, GLSL, Brainfuck and Befunge — and share it as a link.
Project ·
Metadata-driven incremental replication from PostgreSQL into Apache Iceberg — the database counterpart to my structured-logger project.
Article ·
A standalone JavaFX desktop app for inspecting and diagnosing Lucene indexes — documents, analyzers, and vector fields — as a desktop alternative to Luke.
Project ·
A Java library that finds the people, organisations, places, and products in text and works out the sentiment expressed toward each — and who holds it — using a layered ONNX model pipeline.
Project ·
A multi-language code analysis platform that turns repositories into a searchable graph of classes, functions, calls, and dependencies — with a REST API, a web UI, and an MCP server for AI assistants.
Project ·
A TAO-inspired in-memory relationship cache for social-graph queries, with compressed posting lists and fast set operations for friend-of-friend queries and feeds.
Project ·
A metadata-driven structured logging framework: it generates type-safe loggers for Java and Python from JSON definitions and lands every log line in Apache Iceberg tables you can query with SQL.
Project ·
A local log search and analysis tool — Splunk-like search, facets, SQL, charts, and exports running entirely on your own machine, built on Java, Lucene, and Spring Boot.
Project ·
A horizontally scalable web crawler in Java: Kafka distributes URLs across crawler processes, Cassandra keeps the metadata, and S3 or MinIO stores the content.
Project ·
A Java library and discovery server that let Kafka producers and consumers look up brokers and security settings by topic, then talk to Kafka directly.
Project ·
A lightweight reactive API gateway on Spring WebFlux with identity-aware rate limiting, pluggable auth, asynchronous access logging, and a dynamic service registry.
Project ·
A secrets-management server in Go with encrypted storage, path-based policies, versioned secrets, audit logging, leader-follower replication, and client libraries for Go, Java, Python, and Rust.