53 tools, references, and AI explainers in one box. Filtering happens entirely in your browser, so it is instant and nothing you type is sent anywhere.
Paste JSON, get a typed TS interface.
OpenDecode & inspect JSON Web Tokens.
OpenEncode or decode Base64, incl. URL-safe.
OpenBuild & read crontab expressions, in plain English.
OpenCount tokens with the real OpenAI tokenizers.
OpenSee what fills a model's context budget.
OpenFind which files eat your context window.
OpenSchemas for OpenAI, Anthropic, Gemini & JSON Schema.
OpenCompare agent design patterns side by side.
OpenSee how a document splits into RAG chunks.
OpenBuild & validate an MCP server config.
OpenCatch vague, conflicting, or unclear prompts.
OpenEstimate VRAM to run a model locally.
OpenEstimate API cost from token usage.
OpenConvert tabular data both ways, instantly.
OpenGenerate Go structs from any JSON payload.
OpenRedirects & rewrite rules, the easy way.
OpenTurn a cURL command into fetch, axios, or Python.
OpenSwap between YAML and JSON cleanly.
OpenBeautify and standardize messy SQL.
OpencamelCase, snake_case, kebab, PascalCase.
OpenCheck any feed against the spec.
OpenImport, view & convert OPML subscription lists.
OpenEncapsulation, abstraction, inheritance, polymorphism, the four pillars, with examples.
OpenThe classic Gang-of-Four patterns, creational, structural, behavioral, and when to use them.
OpenThreads vs processes, race conditions, locks, deadlocks, and writing thread-safe code.
OpenWhat a memory leak is, the common causes across languages, and how to find and prevent them.
OpenReference counting, ownership, and how unique/shared pointers stop leaks at the source.
Openstatic_cast, dynamic_cast, const_cast and reinterpret_cast, what each one actually does.
OpenFeeds, readers, the orange XML buttons, and how RSS and Atom differ, the basics, clearly.
OpenMethods, status codes, headers, and the request/response cycle behind every web call.
OpenThe protocol that moves email, the SMTP conversation, envelopes, and why mail gets blocked.
OpenThe two protocols for retrieving mail, how they differ, and which one you actually want.
OpenWhat ping really measures, the ICMP echo request/reply, TTL, and reading the results.
OpenWhat a network port is, how a port scan works, the common scan types, and what they reveal.
OpenThe model's working memory, tokens, what fills it, why it runs out, and how to manage it.
OpenHow content becomes a vector that captures meaning, the engine behind semantic search, RAG, and recommendations.
OpenWhere embeddings live, fast nearest-neighbour search over millions of vectors, and the backbone of RAG.
OpenGrounding a model in your own documents at query time, embeddings, retrieval, and why it beats fine-tuning for facts.
OpenWhy an assistant 'remembers' or 'forgets', context vs short-term vs long-term memory, and how persistence is faked.
OpenThe open standard for connecting AI apps to tools and data, the 'USB-C for AI tools.'
OpenHow a model decides to call a function, returns structured arguments, and your code runs it, the basis of agents.
OpenMaking a model return JSON that matches a schema every time, vs JSON mode, and why it powers extraction and tool calls.
OpenSee how your system prompt, history, retrieved docs, and output fill a model's context budget.
OpenDefine fields once; generate the schema for OpenAI, Anthropic, Gemini, and plain JSON Schema.
OpenThe model critiques its own output, then improves it.
OpenThe model classifies the request and routes it to the right path.
OpenOne model evaluates another’s output against a rubric (LLM-as-judge).
OpenCheck the claims before responding.
OpenThe agent requests human approval before it acts.
Openkbcafe.com was a go-to developer resource in the early 2000s. Here's what it is now, and why we brought it back.
OpenEveryone declared RSS dead a decade ago. It's quietly running newsletters, podcasts, and the fediverse the whole time.
OpenLLMs are starving for clean, structured, permissioned content. A 25-year-old format turns out to be a good answer.
OpenNo resource matches that. Try a different term. ☕