Browser-only.
Every value you enter lives in memory for the tab you opened. Close it and the data is gone. Nothing is stored, synced, or transmitted.
A growing library of client-side tools for founders, operators, and growth teams. Calculators, generators, checkers, builders, and branded PDF document templates. Every tool runs entirely in your browser. Nothing is saved, shared, or sent to a server.
We built these for our own team first, then for the operators we work with. They load fast, run in the browser, and stop asking for your email after the third use, because they never asked in the first place. Calculators that tell you the truth about unit economics. Generators that ship valid markup against the schema.org SoftwareApplication spec. Checkers that give you a verdict, not a homework list.
315 free tools in one place — calculators, generators, checkers, builders, branded PDF templates, plus image, PDF, text & code and media utilities. Every one runs 100% in your browser: no upload, no signup. Search by name or by what it does, filter by category, or press Ctrl/⌘ K anywhere to search the whole site.
Build a clean, branded invoice with line items, GST / VAT / sales tax, discounts, and notes. Export to a print-perfect PDF. No signup, nothing stored.
Build a priced quote with line items, tax, discount, and notes. Export as a DH-branded PDF. Presets for agency, consultant, and service work.
Enter revenue, COGS, shipping, fees, ads, and fixed costs. Get gross margin %, contribution margin, profit, and a 12-month projection — the truth about unit economics.
Multi-page statement of work with scope, deliverables, acceptance criteria, and milestones. Branded PDF. Consulting, software, and creative presets.
Fifty candidate brand names across five naming styles: abstract, evocative, compound, founder, and descriptive. Industry-tuned word lists.
Score any blog title, meta title, or ad headline 0–100 on length, power words, emotion, format fit, and SERP-pixel width.
Build pro prompts for images, video & business copy — paste into Midjourney, Sora, ChatGPT.
Make initials avatars & identicons from any name or text — export PNG/SVG.
Generate Code 128 & EAN-13 barcodes and download as PNG or SVG.
Make custom bingo cards from your own word list — multiple unique cards, print-ready.
Generate hundreds of QR codes from a list or CSV — labeled and downloadable as a ZIP.
Create printable certificates — templates, recipient names, dates & signatures, PNG/PDF export.
Convert colors between HEX, RGB, HSL, HSV & CMYK with a live swatch.
Generate harmonious color palettes — lock, tweak, copy & export CSS. Spacebar to reroll.
Box-shadow, gradient, radius & glassmorphism CSS with live preview.
Generate a vCard QR people can scan to save your contact.
Design an HTML email signature with live preview — paste into Gmail/Outlook.
Search 1,800+ emoji by name or category and copy instantly — with recents.
Generate realistic fake names, emails & rows — export CSV/JSON.
Strong, random passwords & passphrases with a strength meter.
Check how strong a password is — entropy, crack-time estimate & tips. Never sent anywhere.
Generate a privacy policy & terms template for your website or app — answer a few questions, export HTML/Markdown.
Make QR codes for links, text, Wi-Fi & more — custom colors + logo.
Scan QR codes with your camera or from an image — decoded locally.
Draw or type your signature and download a transparent PNG — for documents & email.
Generate Luhn-valid test card numbers, CVV & expiry for QA/testing — not real cards.
Crop any photo to a perfect circle or square avatar and export PNG.
Erase image backgrounds automatically with on-device AI — free (one-time engine download).
Stamp text or a logo across many images at once.
Combine photos into a clean grid collage with spacing — export PNG.
See how an image looks with protanopia, deuteranopia, tritanopia & more.
Canva-style design tool — social-size presets, templates, text, shapes & snap guides. Design & export in your browser.
See and strip hidden photo metadata (GPS, camera, date) — privately.
Turn any image into a full favicon & app-icon pack (.zip).
Convert iPhone HEIC/HEIF photos to JPG or PNG — batch, private, no upload.
Mark up screenshots with arrows, boxes, text, blur & numbered steps — export PNG.
Pick colors and extract a palette from any image.
Before/after slider to compare two images side by side — export the comparison.
Shrink JPG, PNG & WebP with a live quality slider — no upload.
Convert between PNG, JPG, WebP & more, right in the browser.
Crop, rotate & flip with aspect-ratio presets.
Blur, pixelate or black-out sensitive parts of an image before sharing — locally.
Resize by pixels, percent or presets — single or batch.
Slice an image into an N×N grid (Instagram grid, tiles) — download as a ZIP.
Turn any image into ASCII art — copy as text or export as PNG.
Convert images to Base64 data URIs (with HTML/CSS/Markdown) and back — locally.
Extract text from images & screenshots in your browser (one-time engine download).
Enlarge images 2×–4× with high-quality resampling & smart sharpening — fully on-device.
Add classic top/bottom captions to any image and export.
Crop photos to passport & visa sizes (2×2", 35×45mm & more) with guides — print-ready sheets.
Add borders, padding, rounded corners & polaroid frames to photos — export PNG.
A full layer-based photo editor — layers, blend modes, filters, brushes, text & transforms. Like Photoshop, in your browser.
Apply filters & adjustments (B&W, vintage, contrast…) and download.
Draw pixel art on a grid — palettes, mirror mode, fill & export PNG at any scale.
Generate sized placeholder images with custom color & label — PNG or SVG.
Drop a screenshot onto a gradient backdrop with padding, rounded corners & shadow — export PNG.
Rasterize SVG to crisp PNG at any scale, right in your browser.
Convert typed text into realistic handwritten pages — paper styles, ink colors, PNG & PDF export.
Turn text into a word-frequency cloud and export PNG/SVG — runs in your browser.
Import or record audio, trim, fade & adjust volume on a waveform — export WAV.
Turn a set of images into an animated GIF — set delay, loop & size, export locally.
Tune guitar, ukulele & bass with live microphone pitch detection — standard & custom tunings.
A precise metronome with tap tempo, time signatures, accents & subdivisions.
Test your microphone, webcam & speakers before calls — levels, preview & devices.
Record your screen (and mic) to a video file — locally.
Dictate and get live transcription in your browser — many languages, copy & download.
Edit subtitles, shift & stretch timestamps, fix sync and convert SRT ↔ VTT — locally.
Turn text into speech with your system voices.
Shrink video file size with quality & resolution presets — in your browser (one-time engine download).
Camtasia-style studio — record your screen, webcam & voiceover, edit on a multi-track timeline with callouts, and export. No upload.
Extract MP3/WAV audio from a video, or convert audio formats — in your browser (one-time engine download).
Trim a video or turn it into a GIF — in your browser (one-time engine download).
Record audio from your mic and download it.
Snap photos from your webcam with filters, countdown & mirror — download locally.
White, pink & brown noise plus rain and fan ambiences with a sleep timer — generated locally.
Grab any YouTube video’s thumbnail in every resolution — just paste the link.
Shrink PDF file size by recompressing pages & images — locally, no upload.
Pull all embedded images out of a PDF and download them (ZIP) — locally.
Turn photos & scans into a single PDF.
Render PDF pages to PNG/JPG at any resolution.
Sejda-style PDF editor — click existing text to edit it (size & font matched), add text, images, shapes, whiteout & signatures. No…
Combine PDFs and reorder pages by drag — locally.
Draw or type a signature and place it on any page.
Extract, delete, rotate & reorder PDF pages.
Extract selectable text from a PDF — by page, copy or download .txt, no upload.
Add text watermarks and page numbers to a PDF.
Turn plain text or Markdown into a clean, downloadable PDF.
Your exact age in years, months & days — plus next-birthday countdown and the day you were born.
Solve width/height for any aspect ratio, with screen & video presets.
BMI, BMR and daily calorie needs (TDEE) — metric & imperial.
Build a 50/30/20 budget from your income — customizable categories with a visual split.
Create an event and download a .ics for Google, Outlook & Apple Calendar.
Daily calories (BMR & TDEE) with activity levels, goals & macro split — Mifflin-St Jeor.
Paste data and get a clean bar, line, pie or donut chart — export PNG.
Project savings & investment growth with contributions and a year-by-year chart.
A big countdown timer and stopwatch with alerts — for events & focus.
Convert between 150+ currencies with editable offline rates (optional live update).
Days between dates, add/subtract time, age & business-day counts.
Plan your day in time blocks on a visual schedule — saved locally.
Can’t decide? Spin a wheel, pick a name, flip a coin or roll dice.
Score options against weighted criteria to find the best choice — saved locally.
Prioritize tasks in urgent/important quadrants — drag between boxes, saved locally.
Live countdowns to your big dates — exams, launches, weddings — multiple events, saved locally.
Log income & expenses by category with totals and a chart — private, export CSV.
Create study decks and review with flip cards & spaced repetition — local.
Trip fuel cost from distance, mileage & fuel price — round trips, cost split between passengers.
Plan a project timeline with tasks and a visual Gantt — export PNG.
Set objectives with measurable key results and track progress — stored locally.
Calculate weighted GPA from your courses, credits & grades.
Weighted course grades & “what do I need on the final?” — categories, weights, targets.
Build streaks with a clean habit grid — stored locally, never uploaded.
Create branded invoices with your logo and export to PDF — all free.
A private kanban that saves to your browser. Export/import JSON.
EMI, total interest & a full amortization schedule for any loan or mortgage.
Timed arithmetic drills — choose operations & ranges, track accuracy and personal bests.
See what a meeting really costs — attendees × salary × time, live.
Brainstorm on an interactive mind map — add, drag, color & collapse nodes, export PNG/JSON.
A fast local notebook with Markdown — stays on your device.
Percentages, % change, discounts and tax/VAT — all in one place.
Interactive periodic table — search elements, view properties, categories & trends.
Focus timer with task list and session stats.
Build a portfolio, CV or resume website from a simple form — 3 themes, live preview, one-file export ready for GitHub Pages.
A beautiful Asana-style board — labels, assignees, due dates, subtasks & drag-drop. Saves locally.
Cryptographically random numbers — ranges, count, unique mode, sorting, lottery & dice presets.
Split a list of names into fair random groups or pairs — perfect for classrooms & teams.
Fill in your details and export a clean, ATS-friendly resume PDF — saved locally.
Convert pay between hourly, daily, weekly, monthly & annual — custom hours and weeks.
A full scientific calculator with functions, memory & history.
Find the best bedtime or wake-up time using 90-minute sleep cycles.
A mini spreadsheet with formulas (=SUM, =A1*B2…) and CSV import/export — runs locally.
Paste numbers for mean, median, mode, std-dev, quartiles & a histogram.
Track recurring subscriptions and see monthly & yearly totals — saved locally.
Add up clock in/out times & breaks for daily/weekly hours, overtime & pay.
Convert any date & time between time zones — DST-aware, with copy-ready results.
Find the best meeting time across multiple time zones.
Split a bill with tip across any number of people, instantly.
A fast daily checklist that saves to your browser — priorities, due dates, drag to reorder.
Measure your typing speed (WPM) and accuracy with timed tests — saved locally.
Convert length, weight, temperature, area, data & more.
Plan a week of meals on a grid and auto-build the grocery list — saved locally.
An infinite canvas to sketch, add shapes, text & sticky notes — export PNG.
Track the current time across multiple cities and time zones at a glance.
Validate, dedupe & clean email lists locally — syntax checks, disposable-domain detection, CSV export.
Turn keywords or a topic into relevant, ready-to-paste hashtags for social.
Analyze 1–3 word keyword frequencies & density in any text or HTML — with target-keyword tracking.
Paste a page’s HTML for an instant on-page SEO audit — titles, headings, alts, OG & more.
Design a 1200×630 social share image with title, gradient & logo — export PNG.
Turn any title into a clean, SEO-friendly URL slug — bulk mode, separators & accent handling.
Compose with a weighted character counter (URLs = 23), thread splitter & live preview.
Generate SEO-optimized YouTube tags from your video title — ranked, deduped, within the 500-character limit. Like RapidTags, but…
Encode & decode text and files to/from Base64.
Encrypt/decrypt with Caesar shift, ROT13 & Atbash — with brute-force decode.
Beautify or minify JSON, CSS, HTML & JavaScript locally.
Write HTML, CSS & JS with a live preview and console — a local CodePen.
Translate a cron expression to plain English and preview the next run times.
Convert CSV to JSON and back, in the browser.
Open a CSV as a sortable, filterable, editable table — export to CSV/JSON.
Paste a curl command and get fetch, Axios, Python requests & PowerShell code instantly.
Turn text into 𝐛𝐨𝐥𝐝, 𝑖𝑡𝑎𝑙𝑖𝑐, 𝓈𝒸𝓇𝒾𝓅𝓉 & 20+ unicode styles — copy for bios & posts.
SHA-1/256/384/512 of text or files via Web Crypto.
Minify HTML, CSS & JS with safe whitespace/comment stripping — live size savings readout.
Encode & decode HTML entities and escape special characters.
Semantic JSON comparison — structural diff that ignores key order and shows added/removed/changed paths.
Beautify, minify & validate JSON instantly.
Turn JSON into TypeScript interfaces/types with flexible options — instantly.
Decode a JWT’s header & payload locally (no data sent).
Write Markdown with live preview & export to HTML.
Build a Markdown (or CSV/HTML) table from an editable grid.
Translate text ↔ Morse code with adjustable audio playback & flashing.
Convert between binary, octal, decimal & hexadecimal.
Convert numbers to words — international & Indian (lakh/crore) systems, plus currency mode.
Convert numbers to Roman numerals and back (1–3,999,999).
Beautify or minify SQL for many dialects — instant, local, no upload.
Run SQL on an in-browser SQLite database; import CSVs as tables (one-time engine download).
Escape & unescape strings for JSON, JS, HTML, URL, SQL, CSV, regex & unicode.
Password-encrypt text or files with AES-256 (Web Crypto) — fully offline.
Convert text to binary, hex, octal, decimal or ASCII codes — and back.
Sort, dedupe, reverse, trim, find-replace & reformat lines of text.
Compare two texts and highlight every change.
Summarize long text into key sentences or bullets — adjustable length, fully on-device.
Convert Unix timestamps ↔ human dates across time zones.
Encode/decode URLs and break them into query parameters.
Generate v4 UUIDs and ULIDs in bulk.
Beautify, minify & validate XML, and convert XML ↔ JSON — in your browser.
Open, inspect & extract ZIP files, or bundle your files into a new ZIP — locally.
Free A/B test sample size calculator. Per-variation sample from baseline conversion rate + minimum detectable effect + statistical…
Free ad creative prompt generator for Midjourney, Pencil, Adcreative.ai. Build platform-native Meta, TikTok, Pinterest, OOH ad briefs…
Free affiliate commission calculator. Per-sale + monthly net (after fees), tier-bonus targets, recurring SaaS lifetime. Flat / tiered /…
Free Shopify SEO anchor text keyword tool. Paste HTML, categorise anchors as branded / URL / generic / partial-match / exact-match,…
Free AOV calculator. Compute average order value, CM per order, channel AOV, and simulate revenue lift from +$5 to +$25 AOV scenarios.…
Free app icon prompt generator for App Store. Pick category, glyph, era, color, background; get Midjourney or Nano Banana ready prompt…
Free Article schema generator with URL + image fields. Fill form, copy JSON-LD aligned with Google Article required fields. Supports…
Free backlink verifier tools. Paste candidate URLs — fetches each, confirms link is live, reports anchor + rel + dofollow. Verifier…
Free blended CAC calculator past Meta vendor dashboards. Sum paid, organic, tools, fees; divide by new customers. True acquisition cost…
Free Shopify bounce rate calculator. Single-page-session %, DTC / blog / B2B / SaaS benchmarks, conversion-lift simulator from a 5-20pp…
Free CSS box-shadow generator with Material Design elevation presets. Stack up to 5 shadows layers, per-layer offset, blur, spread,…
Free brand voice prompt generator for ChatGPT, Claude, Gemini. Build a system prompt with voice archetype, banned words, examples in 60…
Free BreadcrumbList schema generator for any home or page route. Build the navigation trail in JSON-LD with one ListItem per crumb.…
Free break-even calculator. Compute break-even units, revenue, contribution margin, margin of safety, and days from fixed cost per unit…
Free break-even ROAS calculator. Minimum ROAS to break even from contribution margin. Refund-adjusted floor + LTV-aware target.…
Free burn multiple SaaS calculator. Net burn / net new ARR per the David Sacks framework. SaaS verdict tiers + cash-runway sanity…
Free business name generator. Enter a keyword and industry; get 50 brand names across 5 styles: abstract, evocative, compound, founder,…
Free cache headers + max-age checker. Paste curl -I, parses Cache-Control max-age, ETag, Last-Modified, Expires. Letter-grade caching…
Free canonical URL checker tool for Google SEO. Paste page HTML, extracts rel=canonical, validates absolute + HTTPS, flags duplicate…
Free case converter for code variables. Type once, see all 13 cases live: UPPERCASE, lowercase, Title, camelCase, PascalCase,…
Free CDN + edge web detector. Paste curl -I, identifies Cloudflare, Fastly edge, CloudFront, Vercel, Netlify, Akamai web CDN, Bunny +…
Free character counter for content. Count characters, words, sentences, paragraphs, lines, reading time. Tweet, SEO title, meta…
Free churn rate percent calculator for SaaS. Compute logo churn percent, revenue churn, net revenue retention (NRR), annualized churn…
Free CMS detector with platform-confidence score. Paste HTML source, we identify WordPress, Shopify, Squarespace, Wix, Webflow, Ghost,…
Free cohort retention calculator. 24-month survivor curve + half-life from monthly retention rate. SaaS / DTC / mobile presets.…
Free color contrast checker. WCAG AA and AAA ratios for normal text, large text, and UI. Live swatch preview, hex and RGB input,…
Free color palette extractor. Upload image, get dominant + 8-color palette. Hex, RGB, HSL output. Click swatch to copy. Powered by…
Free compression detector + Vary headers audit. Paste curl -I, checks Content-Encoding (gzip / br / deflate / zstd), validates Vary…
Free 5-stage conversion funnel calculator. Identifies leakiest stage by benchmark gap, projects revenue from a +5pp fix. DTC / SaaS /…
Free conversion rate percent calculator with visitors lift. Compute CVR, revenue per visitor, category benchmark, incremental-revenue…
Free page cookies analyzer. Paste Set-Cookie headers, get name / domain / path / expiry / Secure / HttpOnly / SameSite per cookie, plus…
Free Core Web Vitals checker. First Contentful Paint, field data (28-day p75 from CrUX), lab data for LCP, INP, CLS, FCP, TTFB. Mobile…
Free CORS checker API tool. Real browser URL fetch from origin across 4 method requests. Reports exact CORS error or success. Privacy:…
Free Content Security Policy validator with scripts audit. Paste your CSP — get per-directive parsing for unsafe-inline, unsafe-eval,…
Free CSS web development size checker for Google PSI. Live PSI lists every stylesheet with byte size + 1P/3P split + render-blocking +…
Free CTR organic position clicks calculator with 9 channel benchmarks (Google, Meta, Display, TikTok, LinkedIn, email, organic SERP).…
Free DAU/MAU users stickiness calculator. 7 category benchmarks (messaging, social, productivity, B2B SaaS, ecommerce). Habit-tier…
Free CNAME lookup tool for web development. Enter a hostname, queries Cloudflare DoH for canonical-name record, follows alias chain to…
Free DNS domain lookup .com tool. Live A, AAAA, MX, TXT, DMARC, NS, CNAME, CAA records via Cloudflare DNS-over-HTTPS. Browser-only, no…
Free MX record email checker tool. Enter a domain, queries Cloudflare DoH (1.1.1.1) for mail-server records, lists each by priority,…
Free DNS propagation checker tool. Queries Cloudflare 1.1.1.1 and Google 8.8.8.8 in parallel for the same record. Spot global…
Free domain age checker. Cross-references the RDAP registration date with the Wayback Machine's first-capture date. Surfaces…
Free domain authority checker, an alternative signal vs Moz DA + Ahrefs DR. Composite site-maturity score from Wayback age + DNS + TLS…
Free domain availability checker tool. Live RDAP registry lookup tells you which registrar holds any .com / .ai / .io / .co / ccTLD or…
Free composite domain health checker with grade. DNS signal (A/AAAA/MX/TXT), SSL status, domain age, Wayback archive, PageSpeed score…
Free ecommerce profit calculator. Enter revenue, COGS, shipping, fees, ads, fixed costs. Get gross margin percent, contribution margin,…
Free email design prompt generator for Klaviyo, Claude, v0.dev, Postscript. Build subject + preheader + cart-abandon + section spec +…
Free email list growth calculator. Projects subscribers over 12-24 mo from starting list, signup %, churn %. Target line + horizon…
Free Event schema generator with ISO dates. Venue + offers + status. Inline validator catches missing eventStatus, location, organizer,…
Free external link counter. Paste HTML — splits internal vs external, audits rel attributes, flags missing rel=noopener security.…
Free FAQPage schema generator with visible Google Rich result validator. Add unlimited Q+A pairs, valid JSON-LD with required fields,…
Free CSS gradients generator with multi-stop linear, radial, conic. Draggable position stops, live preview, CSS output, Tailwind config…
Free heading hierarchy checker per page for Google SEO. Paste HTML, parses H1-H6 page outline, flags multiple H1s, skipped levels,…
Free heading structure hierarchy outliner services for SEO. Paste HTML, get H1-H6 outline with warnings for missing H1, skipped levels,…
Free headline analyzer. Score blog headlines 0-100 on length, word mix, emotion, power words, clarity, and SERP meta fit. For ad,…
Free hosting provider web development detector. Live DoH lookup + ipapi.co ASN — identifies AWS, GCP, Azure, DigitalOcean, Vercel,…
Free hreflang checker. Paste your page HTML — extracts every rel=alternate hreflang tag, validates ISO codes, x-default presence, and…
Free hreflang generator for Google. Output HTML tags, XML sitemap xhtml:link, or HTTP headers. Built-in reciprocal validator. 4 preset…
Free HTML to Markdown content converter. Paste HTML, live side-by-side preview. GFM extension (tables, strikethrough, task lists).…
Free HTTP headers checker. Paste curl -I or DevTools browser headers. Audits caching, CSP security (HSTS, X-Frame), compression, server…
Free HTTP status code checker. Type URL — live fetch returns status code, content-type, server, response time. Bulk-check up to 20 URLs…
Free HTTP protocol checker. Paste curl -I — header audit identifies HTTP/1.1 vs HTTP/2 vs HTTP/3, validates Alt-Svc. Web development…
Free HTTPS / SSL / TLS checker for any domain. Live reachability + Certificate Transparency lookup (crt.sh) for issuer + cert history +…
Free image alt text checker. Paste HTML; we scan every <img> tag, flag missing alt, empty alt, filename-as-alt, screen-reader and…
Free image format checker. Paste HTML — scans every img tag for format (jpg/png/webp/avif/svg), lazy-loading, srcset, modern-images…
Free Shopify internal links counter tool. Paste page HTML — counts every internal vs external link, lists unique destinations, flags…
Free IP geolocation lookup tool. Enter IPv4 / IPv6 IPs — returns country, region, city, ISP, ASN, timezone. Powered by ipapi.co live…
Free IP lookup tool. Resolves a domain to its A and AAAA records, then performs reverse DNS (PTR) on each IP to surface the hosting…
Free JS framework detector tool. Paste HTML — identifies React, Vue, Angular, Svelte, plus state mgmt (Redux, Zustand, Pinia), routing,…
Free JavaScript web development size checker. Live PSI fetch lists every JS file with size + first-party vs third-party split + INP…
Free JSON validator with deep diagnostics. Paste JSON or NDJSON for strict parse, common-mistake detector, structure stats (depth,…
Free landing page prompt generator for v0.dev, Claude, Cursor. Book a 60-second Tailwind sections spec for any DTC, SaaS, or agency…
Free Lighthouse audit + score checker for any URL. Mobile performance, SEO, Accessibility, Best Practices live via PSI. Mobile +…
Free Google LocalBusiness schema generator with address. Fill form, copy JSON-LD with address, geo coords, weekday hours, telephone,…
Free logo prompt generator for any mark, monogram or wordmark. Pick brand archetype, style, color, form; get a Midjourney or Nano…
Free Lorem Ipsum placeholder generator. Words, sentences, or paragraphs. Four variants: classic Cicero Latin, hipster, designer-jargon,…
Free LTV calculator. Enter AOV, purchase frequency, customer lifespan, and gross margin. Get gross LTV, contribution LTV, and CAC…
Free Markdown to HTML development converter. Live side-by-side preview, GFM CommonMark mode, copy HTML, download .html. Powered by…
Free markup calculator. Bidirectional entry (markup percent, margin percent, or selling price). Industry benchmarks. Markup vs margin…
Free Google meta description checker tool. Paste description or full HTML; we check length (120-155 char), pixel-width truncation, CTA…
Free meta tag generator. Build HTML meta tags, Open Graph, and Twitter Card with live Google SERP, Facebook, and X previews.
Free mobile-friendly test. Live Google PSI mobile audit — checks viewport, tap targets, font size, content width. Verdict + per-issue…
Free SaaS MRR + ARR development calculator. Compute monthly recurring revenue, annualized ARR, net new MRR, growth rate, Quick Ratio…
Free bulk SEO audit. Run Google PSI on up to 5 URLs in sequence — comparison table of Performance, SEO, Accessibility, Best Practices…
Free Open Graph image preview card tool. Test how OG cards and tags render on Facebook, X, LinkedIn, Slack, WhatsApp from any URL.…
Free packaging design prompt generator. Pick product, brand vertical, material, print style, color, and setting; get a Midjourney or…
Free page weight analyzer for web development. PSI byte breakdown by type — HTML, CSS, JS, image, font, third-party. Per-type budget…
Free CAC payback calculator with contribution margin. Enter AOV, repeat rate, gross margin, CAC. Get months to payback, cohort…
Free product photo prompt generator for Nano Banana, Midjourney, Imagen. Build subject + lighting + camera + style + color prompts in…
Free Product schema generator. Fill the form, copy JSON-LD with offers, aggregateRating, brand, GTIN/SKU. Aligned with Google Product…
Free purchase order generator. Issue a buyer-side PO with vendor, ship-to, line items, terms, delivery date. Branded invoice PDF. No…
Free quote generator. Build a priced quote with line items, tax, discount, and notes. Download as a branded PDF. Browser-only, no…
Free readability checker. Paste text; get Flesch Reading Ease, Flesch-Kincaid grade, Gunning Fog, SMOG, ARI scores and sentence-level…
Free reading time WPM calculator with figure-aware count. Live count of words and content reading time across slow / average / fast /…
Free receipt generator. Log a payment with buyer, payer, method, amount, balance, and item detail. Download as a branded invoice PDF.…
Free HTTP redirect chain checker. Paste curl -ILv output — traces 301/302/307/308 redirects hops, flags chain length, mixed status,…
Free regex tester tool. Live URL regex matches, capture groups, named groups, replace preview. JavaScript regex flavor with all flags.…
Free render-blocking resources checker. Live PSI web development LCP audit lists every CSS / JS file blocking initial render with byte…
Free Reviews schema generator for Google rich results. Fill the form for individual Review or aggregate AggregateRating with star…
Free ROAS calculator. Compute per-channel ROAS across Meta, Google, TikTok, and affiliate. Get blended ROAS and break-even ROAS from…
Free robots.txt generator. Presets for Shopify, WordPress, Webflow, Next.js. Individual toggles for every AI crawler (GPTBot,…
Free robots.txt disallow tester. Paste robots.txt and a URL; we run the live RFC 9309 longest-match for Googlebot, Bingbot, GPTBot,…
Free startup runway calculator with cash scenarios. Enter cash on hand, monthly burn, monthly revenue — live runway in months +…
Free SaaS LTV:CAC ratio calculator with monthly churn. Lifetime value, customer acquisition cost, payback period, ratio + verdict band…
Free SaaS magic number calculator. Sales efficiency from new quarter ARR + S&M spend. Verdict bands at 0.5 / 0.75 / 1.0.…
Free SaaS Quick Ratio MRR calculator. (New + Expansion MRR) / (Churned + Contraction). Stage churn verdict for seed, Series A/B/C,…
Free schema markup generator. Valid JSON-LD for Article, Product, FAQPage, LocalBusiness, Event, and BreadcrumbList. Tested for Google…
Free SERP preview generator. See your title, URL, and meta description rendered as a Google search-result title snippet, mobile +…
Free Shopify discount URL generator. Build auto-apply discount share links with optional product, redirect path, and QR code download.…
Free Shopify rebuild ROI calculator. Enter GMV, conversion lift percent, AOV lift, build cost. Get payback month, 12-month return, and…
Free Shopify speed test with score. PageSpeed data, Shopify apps detection (Klaviyo, Yotpo, Judge.me), Core Web Vitals, per-app weight…
Free site health checker via Google Lighthouse PSI. 4-cat composite (Performance + SEO + A11y + Best Practices) → grade + top 5 fixes.…
Free slogan generator for product brands. Enter your brand and offering; get 40 slogans and taglines across 5 tones: confident, warm,…
Free social post prompt generator. Pick platform, goal, format, voice, length, CTA, and hashtag style; get a ChatGPT or Claude ready…
Free SOW generator for client work. Build statement with scope, deliverables, milestones, acceptance criteria, priced phases. Branded…
Free SPF, DKIM, and DMARC checker tool. Enter a domain — queries Cloudflare DoH for the email-auth TXT records and validates SPF…
Free SSL certificate inspector tool. Pulls the most-recent cert from public Certificate Transparency logs (crt.sh) and lists SAN domain…
Free SSL expiry monitor tool. Paste up to 20 hostnames at once for cert expiry — days-remaining + renewal status per .com / .net domain…
Free A/B test significance calculator. Control + variant lift, two-proportion z-test, p-value, confidence, lift %. Verdict at 90/95/99%…
Free structured data validator tool. Paste JSON-LD or microdata; we parse, walk every node, and check required fields, ISO formats,…
Free subdomain finder tool. Enumerates every public sub-domain .com ever issued an SSL certificate via crt.sh Certificate Transparency…
Free SVG optimizer tool. Strip XML comments, editor metadata (Inkscape, Adobe, Sketch), redundant default attributes. Rounds decimals.…
Free tech stack detector tools. Paste HTML — we identify JS framework, CSS framework, analytics, payment, ads, chat, CRM, A/B test…
Free title case converter with AP, Chicago, MLA, APA, NYT, Wikipedia sentence-case modes. Handles prepositions per style. Browser-only,…
Free title tag checker brand keyword tool. Paste a title or full HTML; we run length, pixel-width, brand-presence, capitalization, and…
Free Twitter Card validator with summary preview. Paste page HTML — extracts every twitter:card / title / description / image meta tag,…
Free user agent parser tool. Paste a UA string — Chrome/Mozilla version, browser, OS, device, engine, bot detection. Auto-fills your…
Free UTM builder. Tag paid campaign URLs with UTM parameters. Platform presets for Meta, Google, TikTok, LinkedIn, Email, Klaviyo. QR…
Free Wayback Machine viewer tool. Find the first archived domain URL capture plus year-by-year snapshots back to 1996. Browser-only, no…
Free web server CDN origin stack detector. Paste Server / X-Powered-By / response headers — we identify nginx, Apache, IIS, Caddy,…
Free website audit tool. Enter a URL, get a Digital-Heroes-branded scorecard across Performance, SEO, Accessibility, and Best…
Free website hero prompt generator for v0.dev, Claude Design, Cursor, Lovable. Build a hero brief with primary layout, copy direction,…
Free WHOIS lookup. Real registrar, creation date, expiration, name servers, and status from the live RDAP registry. Browser-only, no…
Free XML sitemap generator. Paste URLs or upload CSV, set priority, changefreq, lastmod, image + hreflang annotations. Auto-splits…
Free XML sitemap URLs validator. Paste a sitemap.xml; we parse it, check urlset namespace, validate every URLs loc / lastmod /…
Free YAML validator. Live syntax check, parse-error line + col, indentation rules, JSON-equivalent view, common-mistake detector (tabs,…
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compress · convert · crop · resize · remove background · upscale
merge · split · sign · compress · to-text · watermark
JSON · regex · case · markdown · CSV · counters · encoders
invoices · QR · names · slogans · AI prompts · CSS · favicons
schema · meta · sitemaps · audits · Core Web Vitals · redirects
profit · CAC · LTV · ROAS · retention · planners · trackers
record · trim · transcribe · GIF · audio · captions
Every tool on this page runs entirely in the browser using standard Web APIs. No server receives the numbers you enter. No analytics beacon carries your business data to a third party. No account gates the output. The tools that pay for themselves on DH's side are the ones honest operators use and share; the ones that try to extract email addresses rarely make it to that group. Performance budgets follow Google's Page Experience signals.
Every value you enter lives in memory for the tab you opened. Close it and the data is gone. Nothing is stored, synced, or transmitted.
Every tool has a "Copy results" button that puts a clean plain-text summary on your clipboard, ready to paste into a board deck, a Slack message, or an email.
Each tool names the bracket your number falls into and what the next action usually is. If the honest answer is "this is fine, no work needed", the verdict says that.
Most "free" tool sites gate results behind a signup wall, inject a chat widget that pulls you into a sales funnel, or save your numbers server-side for retargeting. We don't. The tools here work end-to-end without an account, and none of your inputs leave your browser. Accessibility follows the WCAG 2.1 quick reference, and feature support is verified against Can I Use before shipping. The ones that send us business are the ones an operator uses at 11pm on a Tuesday and shares with a colleague at 9am Wednesday.
"The invoice generator is the first one I've used where I didn't have to watch for an upgrade dialog. I bookmarked it on three machines."
The tools on this page diagnose. The team behind them ships the fix. Each link below opens a deeper page: scope, methodology, outbound authority references, FAQ, and the team that ships the work. The structured data on every tool follows Google's SoftwareApp rich-result spec.
Liquid, sections, Functions. Plus + B2B fluent.
Premier-partner-grade work for $2M+ DTC brands.
Editorial design that converts. Mobile-first, WCAG-baked.
Next.js, Webflow, WordPress. CWV green on launch.
React Native, Flutter, iOS, Android. Companion + standalone.
Stripe, Postgres, Next.js. First customer in 8 weeks.
Logo + type + color + voice. Brand books that stick.
Block themes, custom plugins, headless. Editor-first.
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