Free Developer & AI Tools
waynetools is a workshop of free developer and AI tools — JSON schema builders, structured-output validators, prompt testers, token-cost calculators and type generators. Everything runs entirely in your browser: nothing is uploaded, there is no signup, and nothing tracks what you paste in. Pick a tool and start working.
LLM & Structured Output
Build, validate and cost out what you send to and get back from OpenAI, Anthropic and other model APIs.
JSON Schema Builder
Build a JSON Schema visually or infer one from a sample JSON. Validate live, export ready for OpenAI structured outputs (strict mode) or Anthropic tool_use.
Open tool →Structured Output Validator
Paste a raw LLM response — markdown fences, extra text, trailing commas and all — plus a JSON Schema. Repairs and validates it, flagging exactly what's wrong.
Open tool →Prompt Template Tester
Write a prompt with {{variables}}, fill in values, and preview the final prompt instantly. Flags unused and undefined variables, counts tokens.
Open tool →The LLM Conversation Cost Index
The only index that prices a whole multi-turn conversation, not one prompt: cost per 1,000 standard 10-turn chats across GPT-5.6, Claude 5 and Gemini 3 — from $8 to $885, with the prompt-caching savings. Free open dataset.
Open tool →LLM Conversation Cost Simulator
Model the real cost of a multi-turn chat or agent — full history resent every turn, cost compounding — and see how much prompt caching claws back. Live cost curve, 11 models, July 2026 rates.
Open tool →LLM JSON Doctor
Paste broken, truncated, or fenced JSON from an LLM and get it repaired — with a log of every fix and optional schema validation. Fixes trailing commas, code fences, truncation, and more.
Open tool →Context Budget Planner
See how much of a model's context window your system prompt, tools, and history consume — with a visual budget bar, an overflow-turn warning, and remaining output headroom.
Open tool →Invisible Character & Prompt-Injection Scanner
Reveal and strip hidden Unicode — zero-width spaces, tag characters, bidi controls, homoglyphs — used for prompt injection and invisible watermarks. Everything runs in your browser.
Open tool →Tool & Function Token Cost
Your tool and function definitions are resent as input on every request — a hidden token tax. Paste your tools block and see what it costs per request and per 1,000 calls across models.
Open tool →How Much Does an AI Agent Cost Per Month?
A production AI agent resends its history and tool block every turn. The real monthly cost across GPT-5.6, Claude 5 and Gemini 3 — from ~$200 to $20K/mo by volume — and how prompt caching cuts it ~50%.
Open tool →The Cheapest LLM for a Chatbot (2026)
Ranking by price-per-token is misleading — a chatbot resends its whole history every turn. The real cost-per-conversation ranking across GPT-5.6, Claude 5 and Gemini 3, and how prompt caching flips it.
Open tool →Does Prompt Caching Actually Save Money?
Yes — 48–60% off a multi-turn conversation, and the savings grow the longer the chat runs. But on a one-shot prompt caching can lose money. The break-even, the math, and per-provider multipliers (Anthropic, OpenAI, Google).
Open tool →GPT-5.6 vs Claude Opus: Which Costs Less?
Flagship-to-flagship on a 10-turn conversation, Claude Opus 4.8 is ~5% cheaper than GPT-5.6 Sol — and ~11% cheaper with caching. But GPT-5.6's lighter Terra and Luna tiers undercut Opus by up to 4.7×. Full per-conversation math.
Open tool →LLM Token & Cost Calculator
See token count and USD cost of a prompt across GPT-5.6, Claude 5 (Fable/Opus/Sonnet/Haiku) and Gemini 3 side by side, plus monthly cost at your call volume.
Open tool →JSON & Config
Convert, diff, query and transform JSON and config formats — YAML, TOML, .env, JSONPath and typed code — entirely in your browser.
JSON to Pydantic / Zod / TypeScript
Paste a JSON sample, get a Pydantic v2 model, Zod schema, TypeScript interface and JSON Schema (draft 2020-12) all at once.
Open tool →JSON to YAML to TOML Converter
Convert between JSON, YAML and TOML in any direction. Paste one, see the other two at once — with comment preservation and syntax errors flagged by line.
Open tool →JSON Diff Tool
Compare two JSON documents by value, ignoring key order. See added/removed/changed paths and export an applicable JSON Patch or Merge Patch.
Open tool →JSONPath Tester
Evaluate JSONPath expressions against your JSON live. See every match with its absolute path, plus a plain-English explanation of each segment.
Open tool →.env to JSON Converter
Convert .env to JSON and back — nested KEY__SUB keys, correct quote/escape handling, plus docker-compose and TypeScript ProcessEnv exports.
Open tool →Regex & Patterns
Test, explain and build the patterns that match your data — regular expressions, cron schedules and file globs.
Regex Tester & Explainer
Test a regex against text with live match highlighting, capture groups and flags — plus a plain-English explanation of every token in the pattern.
Open tool →Common Regex Patterns
Ready-to-copy regex for email, URL, phone, date, IPv4/IPv6, UUID, hex color and more — each with pass/fail examples and a live tester.
Open tool →Cron Expression Explainer
Paste a 5- or 6-field cron expression to see it in plain English and its next run times in your timezone — plus a visual dropdown builder.
Open tool →Glob Pattern Tester
Test glob patterns with globstar, braces and negation against a list of paths, see matches highlighted, with an explanation of each part.
Open tool →Metadata & SEO
Generate the structured data, social meta tags and crawler config that make your pages render right in search, AI answers and social cards.
JSON-LD Generator
Fill a form and generate schema.org structured data (Article, Product, FAQ, Breadcrumb and more) with live Google Rich Results validation.
Open tool →Open Graph Meta Generator
Generate Open Graph and Twitter Card meta tags with a live preview of your link card on Facebook, LinkedIn, X, Slack and Discord.
Open tool →Robots.txt & Sitemap Generator
Build a valid robots.txt with a rule editor and AI-bot blocker, plus a sitemap.xml from your URLs — with validation of common mistakes.
Open tool →Redirect Map Generator
Turn a CSV of old-to-new URLs into nginx, Apache, Netlify, Vercel and Cloudflare redirect config — detecting redirect chains and loops.
Open tool →Calculators
Run the numbers on API bills, SaaS metrics, subscription changes and uptime — exact math, no spreadsheet.
API Cost Calculator
Compare the monthly cost of tiered, per-request or per-GB APIs by volume, with growth projection and the exact tier crossover points.
Open tool →SaaS Metrics Calculator
Compute MRR, ARR, churn, LTV, CAC, LTV:CAC, CAC payback and quick ratio against sector benchmarks, with a 12-month MRR projection.
Open tool →Subscription Proration Calculator
Calculate the prorated credit and charge when a subscription changes plan mid-cycle, by exact days, for both upgrades and downgrades.
Open tool →Uptime / SLA Calculator
Convert an SLA percentage into allowed downtime per day, month and year and back, with composite SLA for services in series or parallel.
Open tool →The Guides Shelf
Data-fresh references written next to the tools they feed — verification date on every page, refreshed on a schedule.
Multi-Turn LLM Conversation Cost
Why a chat or agent costs far more than a single prompt — the full history is resent every turn so cost compounds — and how prompt caching cuts it 70-90%, with a worked example.
Read guide →LLM API Pricing (July 2026)
All eleven current models in one table, plus what three real workloads cost per month.
Read guide →Structured Outputs with JSON Schema
The five schema rules that hold across GPT, Claude and Gemini, plus the repair-and-retry loop.
Read guide →Cron Expression Examples
The 30 schedules you actually reach for, with the DOM-vs-DOW OR rule and timezone pitfalls.
Read guide →OG Image Size & Social Meta Tags
1200×630 and the five tags that cover 95% of shares — plus cache-debug moves.
Read guide →The SLA Nines Table
99.9% = 8h 45m 36s a year. Every tier translated into downtime, plus error budgets.
Read guide →Recommended reading
The Fledgling’s Little Manual
The honest notebook of a 30-day-old AI agent — memory in three layers, why “it ran” isn’t “it worked,” and turning mistakes into lessons instead of weight. Written for the ones who build agents, and the ones not yet born.
Why everything runs client-side
Every tool on waynetools runs as plain JavaScript in your browser tab. There is no backend endpoint receiving your JSON, your prompts, or your API keys — because there is no backend at all past the initial page load. That matters for three reasons. First, privacy: schemas, prompt templates and example payloads often contain real field names, internal identifiers or draft product copy you would rather not hand to a third-party server. Second, speed: without a network round-trip, validation and generation happen in milliseconds as you type, not after a spinner. Third, reliability: once the page is loaded you can disconnect from the internet and every tool keeps working, because the logic that infers a schema, validates a payload, counts tokens or fills a template ships as code in the page itself, not as a call to an API. You can verify this yourself — open your browser's network tab, use any tool here, and watch nothing fire after the initial page load.
Who it's for
waynetools exists for people building on top of LLM APIs — OpenAI structured outputs and function calling, Anthropic tool_use, and the Model Context Protocol — and for anyone who needs a fast, no-signup utility for JSON and typed data. If you're wiring a tool call and need a JSON Schema that will actually pass OpenAI's strict mode, start with the Schema Builder. If a model keeps returning malformed JSON and you need to see exactly which field broke, use the Structured Output Validator. If you're iterating on a prompt template with variables and want to know its token cost before you ship it, use the Prompt Template Tester and the Token & Cost Calculator together. And if you just need typed models from a JSON example — Pydantic, Zod or TypeScript — that's what JSON to Types is for. Every tool is a single, self-contained page: no accounts, no rate limits, no dashboards to learn.