Tools

Estimate your monthly LLM inference bill and compare models across OpenAI, Anthropic, Google, and more.

Paste a prompt, get an approximate token count and what it costs as input across every major LLM.

Is ChatGPT Plus or Claude Pro worth it vs paying per token? Find your break-even point.

Paste your prompt stack and see which LLMs fit — with a bar showing how much of each model’s context window you use.

Compare two prompt variants: token delta and dollar savings per model, per call and per month.

Estimate embedding API cost, chunk counts, vector storage size, and rough monthly bills for your corpus.

Estimate LLM response time by output length — compare time to first token and total wait across models.

See how multi-step agent runs get expensive as context grows each step — per-step cost table with monthly totals.

Seven questions to pick budget, workhorse, or flagship LLM tier — with honest advice to start cheap.

Seven questions to pick fine-tuning, RAG, or prompt engineering — with honest cost ranges and anti-recommendations.

Lint system prompts in your browser: contradictions, vague wording, missing format spec, wasted tokens. Rule-based, not AI.

Get a web app idea to build for practice or a tutorial: curated ideas with features, or generate a fresh one with AI.

Estimate VRAM for quantized weights plus KV cache, and see which RTX cards and Apple Silicon tiers fit your model.

Buy a GPU or pay per token? Amortized hardware + electricity vs API pricing, with the break-even point in months.

Chunk count, embedding cost, vector storage size, and whether top-k retrieved chunks actually fit your context window.

Test regular expressions with live match highlighting and a plain-English breakdown of the pattern.

Validate, pretty-print, and minify JSON with clear error messages. Runs entirely in your browser.

Decode JSON Web Tokens client-side: header, payload, claims explained, and expiry status. Nothing leaves your browser.

Paste JSON and generate TypeScript interfaces with nested types and optional keys — entirely in your browser.

Pick locale and date parts, see live Intl output, and copy snippets for Intl, date-fns, or Temporal.

Compare two values with ==, ===, and Object.is — see the coercion steps and classic gotcha presets.

Tweak Intl.NumberFormat options for locale, currency, and notation — live output plus a copy-paste snippet.

Convert one string to camelCase, snake_case, kebab-case, and six more cases with copy buttons per row.

Paste a URL to see every part labeled — protocol, host, path, query params, hash. Edit any piece and copy the result.

Encode or decode Base64, URL components, and HTML entities in your browser. Unicode-safe Base64 included.

Generate UUID v4, nanoid, or ULID strings in your browser — with collision-probability math for nanoid.

Step through JavaScript event loop examples: call stack, microtask queue, macrotask queue, and console output.

Answer six questions and get a commented tsconfig.json for TypeScript 5.x — browser, Node, or library setups.

Escape and unescape JavaScript strings, JSON strings, hex bytes, and Unicode sequences — with a swap button.

Why .length lies: UTF-16 units vs code points vs graphemes vs UTF-8 bytes, plus hidden-character detection and clean copy.

Live conversion between binary, octal, decimal, and hex — BigInt-backed, with two’s complement and a nibble explainer.

Pick a goal, get the right array method with a snippet, mutating badges, gotchas, and a searchable full reference.

Promise.all vs allSettled vs race vs any — answer three questions, then watch simulated promises settle on a timeline.

Diff two dates, add or subtract durations, or count down — with business days and vanilla/date-fns/Temporal snippets.

Build multi-key JS sort comparators visually, preview on your JSON, and copy clean compare functions.

Paste a UUID or ULID: version, variant, embedded timestamps decoded — and why v7 is the DB-friendly choice.

Build and sign HS256 JWTs with Web Crypto, or verify a token against a secret. Secrets never leave your browser.

Toggle flex container and item properties, see the layout update live, and copy the generated CSS.

Paint named grid areas on a clickable grid, preview the layout, and copy grid-template-areas CSS plus HTML.

Stack up to three box shadows, tweak border-radius per corner, preview the result, and copy the CSS.

Convert CSS colors between hex, rgb, hsl, and oklch, then check WCAG 2.1 contrast ratios for text on a background.

Convert between px, rem, em, %, and pt with a configurable root font size, plus a quick px→rem reference table.

Compute fluid typography clamp() from min/max font sizes and viewport widths — with the slope math shown.

Paste CSS selectors and get the (a, b, c) specificity triple for each — ranked so you can see which rule wins.

Generate title, description, canonical, Open Graph, and Twitter Card tags — with SERP and social card previews.

Pick platforms to support and get a modern favicon file checklist plus copy-paste link tags and manifest snippet.

Search common HTML entities by name, number, or character — copy named or numeric forms, or encode arbitrary text.

Encode SVG markup into CSS-ready data URIs — URL-encoded vs base64 byte counts, background-image and mask snippets.

Compare CSS timing functions side by side with live animations and cubic-bezier curve plots — copy the one that feels right.

Build linear, radial, and conic gradients with a stops editor and presets — copy clean, ready-to-paste CSS.

Generate responsive srcset, sizes, and <picture> markup from a filename pattern — see which file the browser would pick.

Test any selector against pasted HTML — match list, source highlighting, and specificity, all in your browser.

Convert dimensions to ratios, lock a ratio while resizing, and compute contain/cover letterbox and crop math.

Build @keyframes animations step by step with a live preview and a prefers-reduced-motion wrapper included.

Search or browse 75+ Git commands by goal — undo commits, branches, remotes, stash — with caution notes for destructive ops.

Check your stacks (Node, macOS, VS Code, Python, Astro, env files) and copy a commented .gitignore.

Answer what went wrong — wrong branch, lost commits, committed secrets — and get step-by-step recovery commands.

Build Conventional Commits messages with live validation, breaking-change footers, and copy-ready one-liners.

Pick what changed for the correct semver bump (including 0.x rules), plus plain-English explanations for ^ and ~ ranges.

Convert Unix permissions between rwx checkboxes, octal (755), and ls -l notation — with common presets.

Search HTTP status codes 1xx–5xx with plain-English meanings and practical when-to-use notes.

Convert .env files to JSON or YAML and back, in your browser — comments, quotes, and multiline values handled.

Build curl, fetch(), and httpie commands from method, URL, params, headers, and JSON body — with copy button.

Estimate bcrypt and argon2 hash times and rough offline crack timelines — educational, not a benchmark.

Compare min+gzip bundle sizes for ~40 common npm packages and see lighter alternatives.

Pick a Node LTS version to see its features, or pick a feature to see which version you need.

Paste a curl command and get fetch(), Node.js, or Python requests code — headers, auth, form data, and JSON bodies handled.

SHA-1/256/384/512 and MD5 digests plus HMAC signing, from text or files — hex or Base64, all in your browser.

Describe what you want in plain English and get the exact tar, find, or rsync command with every flag explained.

Test glob patterns against a file list with gitignore or minimatch semantics — see exactly what matches and why.

KB vs KiB conversions done right, plus transfer times at common connection speeds — no more 1000 vs 1024 confusion.

Six questions to pick SQLite vs Postgres vs KV vs columnar — with honest anti-recommendations and typical pricing.

Pretty-print SQL in your browser — keyword casing, clause breaks, indentation, or compact minify.

Convert a CREATE TABLE to Prisma and Drizzle — or paste Prisma or Drizzle and get SQL back.

Describe your query pattern and get a suggested CREATE INDEX with plain-English reasoning. Verify with EXPLAIN.

Build or parse Postgres, MySQL, and SQLite connection strings. Passwords stay in your browser.

Head-to-head comparison of the three classic relational engines, plus a four-question helper with honest tradeoffs.

Pick the right React hook for your goal — with snippets and honest "you probably don’t need useEffect" notes.

Ten questions on React keys, reconciliation, and memo — instant feedback, code snippets, shareable score.

Six questions to choose static, ISR, SSR, or client rendering in Next.js — with the exact code convention to use.

Stack simulated Astro islands by framework and client:* directive — see approximate JS shipped vs a 100 KB budget.

Build complete hx-* attributes from a form — live HTML output, plain-English readback, and copy button.

Alpine core directives with snippets and live mini-demos — this page is built with Alpine itself.

Build Cache-Control headers for static assets, HTML, APIs, or private pages — with plain-English browser vs CDN readback.

Describe a cross-origin request and see simple vs preflight, the required response headers, and fixes for classic errors.

Compose a Content-Security-Policy header with presets, per-directive explanations, and warnings on unsafe-inline.

DNS record reference (A, MX, TXT, and more) plus a helper for pointing domains, email setup, and anti-spoofing.

IPv4 CIDR and netmask calculator with network/host breakdown, binary view, and a prefix finder for N hosts.

Six questions to pick WebSocket, SSE, or HTTP polling — with a comparison table and anti-recommendations for serverless.

Paste _redirects rules, test paths, and see first-match results with splat substitution and rule-order warnings.

Build or paste a cron expression, get a plain-English explanation, and see the next 5 run times in your timezone.

Unix timestamp to date and back — local, UTC, and any timezone, with a live clock and JS snippets.

Paste response headers and get each one explained — plus warnings for missing security headers like HSTS and CSP.

Paste a Cookie or Set-Cookie header to inspect it, or build a Set-Cookie line with SameSite, HttpOnly, Secure, and Partitioned — all in the browser.

Generate a starter set of HSTS, nosniff, Referrer-Policy, Permissions-Policy, framing, COOP, and CORP headers — raw, nginx, or Cloudflare format.

Generate ETags, set If-None-Match / If-Modified-Since, and see whether the server should answer 200 or 304.

Paste an Accept header, list what your server offers, and see which MIME type wins — plus Accept-Language and Accept-Encoding.

Permanent or temporary? Keep the method or switch to GET? Pick 301, 302, 303, 307, or 308 with a sample Location response.

Build robots.txt rules with AI-crawler presets, then test any path and user-agent against them before you deploy.

Generate and explain email authentication DNS records — get your newsletter out of the spam folder.

Seven honest questions about your team, services, and traffic — verdict tiers from "No" to "Yes, you have K8s problems".

What’s actually slow, is it stateful, how spiky is traffic — one primary scaling strategy with honest anti-recommendations.

App type and daily visitors in, recommended server tier out — with the req/s and memory-budget math shown.

Turn an SLA percentage into allowed downtime per day/month/year, and see what chaining dependencies does to real availability.

Generate nginx server blocks for static sites, SPAs, and Node.js reverse proxies — HTTPS with certbot, gzip, cache headers.

Generate a compose.yaml for your Node.js, Astro, or Next.js app with Postgres, MySQL, Redis — healthchecks wired correctly.

Generate a systemd unit file to run a Node.js app as a Linux service — restart policy, boot, memory limits, hardening.

Complete deploy.yml for Cloudflare Pages, Fly.io, VPS over SSH, or npm publish — plus the exact secrets to set.

Interactive SSH server hardening checklist with a live sshd_config generator — keys only, fail2ban, safe restart commands.

Compare Docker base images — alpine, slim, distroless, scratch — by pull size, shell, and libc, with a 3-question picker.

Builds per day × duration → monthly CI minutes and estimated bills on GitHub Actions, GitLab CI, and CircleCI.

Pre-launch checklist tailored to your stack and platform — security, backups, DNS cutover, rollback — with shareable progress.

Five questions to pick Cloudflare KV, D1, R2, or Durable Objects — with anti-recommendations and a comparison table.

Estimate monthly Cloudflare Workers, KV, D1, R2, and Durable Objects cost with plan allowances subtracted.

Page views × page weight × cache hit rate → monthly bandwidth and what it costs on the major static hosts.

What can you run for exactly $0? Every genuinely free tier from Cloudflare, Vercel, AWS, Fly.io, and Railway, filtered by what your app needs.

Project SaaS MRR over 24 months from traffic, trial conversion, churn, and visitor growth — with steady-state estimate.

Work out the hourly and day rate you need after tax, overhead, and business costs — with realistic personas.

Convert between hourly, day, weekly, monthly retainer, and project rates — with retainer discount math.

What freelance revenue do you need to match an employee salary? Country presets, benefits, bench time — ballpark only.

Test a price change with elasticity presets; see projected revenue, break-even drop-off, and a price-range table.

Estimate course or ebook launch revenue from list size, email funnel rates, price, and launch sequence style.

Compare net revenue on Paddle, Stripe, Gumroad, Polar, and Lemon Squeezy for your price and monthly volume.

Project newsletter subscribers over 24 months from daily signups and churn — with 1k/10k milestone timing.

Estimate ad and sponsorship rates for your blog or newsletter from traffic, niche, and placement — with the CPM math shown.

Turn a blog topic into SEO title ideas, a URL slug, and a meta description skeleton — rule-based templates, no AI.

Plan blog posts, handbooks, or books: sessions needed, finish date, and week-by-week milestones from your writing pace.

Paste text for word count, reading time, speaking time, and sentence stats. Your text never leaves the browser.

Slugify any headline for URLs and convert between title case, sentence case, and more — AP and Chicago styles included.

Check your text against SERP title, meta description, tweet, Open Graph, and email subject limits — all in one view.

Find meeting times that work across cities with a color-coded overlap grid — working hours, early, late, or asleep.

Customer lifetime value from ARPU and churn, CAC payback months, and what halving churn does to your revenue.

Build a clean, print-friendly invoice in the browser and save it as PDF — no signup, nothing uploaded anywhere.

Break work into tasks, apply uncertainty buffers, and get a realistic range estimate instead of a single wrong number.

Generate Dockerfiles for Node.js, Next.js, Astro, Bun, and static sites — with .dockerignore and build commands.

Build markdown tables in an editable grid — paste from Excel or Sheets, set alignment, copy pretty-printed output.

Live markdown to HTML preview with GFM quirks explained — raw HTML in the input is safely escaped.

Compare two text blocks line by line — unified or side-by-side view, ignore-whitespace option, change stats.

Generate seeded fake JSON for users, products, orders, posts, and companies — reproducible fixtures to copy or download.

Convert YAML to JSON and back with indent options, line-number errors, and warnings for classic YAML gotchas.

JSON arrays to CSV and back — nested-object flattening, delimiter auto-detect, type inference, proper RFC 4180 quoting.

Turn images into data URIs (or decode base64 back to a preview) with HTML and CSS snippets — files never leave your browser.

Format or minify HTML, CSS, and JavaScript in your browser — with before/after byte counts.

Paste HTML, get JSX — className, style objects, self-closed tags, SVG attributes, and comments handled.

Sort, dedupe, filter, trim, and transform lines of text — operations compose, with live in/out stats.

Classic lorem ipsum plus dev ipsum and fake commit messages — seeded and reproducible, as text, HTML, or markdown.

Passwords, passphrases, PINs, and random bytes via crypto.getRandomValues — with entropy bits and time-to-crack estimates.

QR codes for URLs, text, or WiFi networks — SVG and PNG export, generated entirely in your browser.

Paste markdown, get an anchor-linked table of contents — GitHub-style slugs, duplicate handling, indent options.

Resize and compress images right in the browser with before/after sizes — files never get uploaded anywhere.

See what metadata your photos leak — camera, settings, GPS location — and strip it all client-side before sharing.

What does your stack say about you? Eight questions, one archetype: Hetzner Monk, Serverless Maximalist, or worse.