usefulweb.site: 239 focused tools that just work
Calculators, checkers, planners and technical explorers with transparent assumptions. Every tool gives people a clear page and gives AI agents the identical result as JSON, OpenAPI and MCP.
Free tools that show their work
usefulweb.site is a collection of 239 free tools for everyday questions and technical checks: loan and savings calculators, travel and household planners, document and media converters, and checkers for websites, code and infrastructure. Each tool does one job, needs no account and works in any browser — most of them even without JavaScript.
Results come from deterministic programs, not from a chatbot: the same inputs always give the same answer. Every tool page explains its method and assumptions, names its sources and offers worked examples, and about 2,700 automated tests run before each release. Scripts and AI agents get the identical calculation through the JSON API and MCP.
The site is run by Marcel Flaig, an independent developer in Germany. Spotted a mistake? Every page has a feedback button, and corrections are fixed in the next release. About usefulweb: who runs it and how the tools are checked →
Start here
Popular everyday tools to try first:
- Loan Amortization Calculator Annuity, linear or interest-only loans: schedule, extra payments, fixed-rate balance, APR.
- Percentage & Ratio Calculator X% of Y, % change, reverse %, percentage points, ratios and aspect ratios, with formulas.
- Tip & Bill Split Calculator Tip, tax and who pays what: split a bill equally, by shares or by items, rounded up.
- Password & Passphrase Generator Strong random passwords and passphrases, made in your browser, with exact entropy.
- Currency Converter Convert an amount into several currencies at ECB euro reference rates, with rate date and source.
- Running Pace & Splits Pace, time or distance in km or miles, splits, race predictions, treadmill speed, laps.
- RuleDate Deadline Calculator Business-day and deadline maths with public holidays and a step-by-step rule trace.
- UnitProof Unit Calculator Unit maths you can audit: dimension check, exact factors and a full derivation tree.
Latest from the blog
Premium apps
Full software programs, free in your browser. No sign-up, your projects stay on your device, and every engine is also available to AI agents.
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Kerfwise
Cabinet & furniture CAD
Design cabinets and furniture, get cut lists, optimised sheet layouts, costs and drawings.
- 16 parametric cabinet & furniture types incl. diagonal, L-shaped and angled corners
- Kitchen planner: snapping runs, mitred or one-piece L worktops
- Cut list + polygon-aware sheet nesting with lower bound
- CNC G-code (GRBL, LinuxCNC, Fanuc) with drilling and toolpath preview
- Costs, hardware, drawings, DXF/SVG/CSV export
- Runs in the browser, saves locally, free
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Kinetica
Robot motion studio
Simulate robot arms in your browser: kinematics, trajectories, collisions, program export.
- Jog a 6-axis arm and drag its TCP with live inverse kinematics
- PTP, LIN and CIRC moves with S-curve profiles and blending
- Collision and self-collision checks along the whole path
- URDF, CSV, G-code and KRL/RAPID-style program export
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Threadsmith
Embroidery digitizing studio
Draw or import artwork, turn it into stitches, export DST, PES, JEF or EXP files.
- Running, satin, tatami, contour and motif stitches with real underlay
- Built-in embroidery lettering (also on an arc), SVG import and bitmap auto-trace
- Thread-look preview, stitch-out simulator and density heat map
- Exports Tajima DST, Brother PES, Janome JEF and Melco EXP — every file re-read and verified
- Free, local-first: autosaves in your browser, no account
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Ohmforge
Virtual electronics workbench
Draw a circuit, switch it on, and measure it with real-feeling bench instruments.
- Schematic editor + SPICE-style simulator in the browser
- Oscilloscope, multimeter, Bode plotter, generator, bench supply and parameter sweep
- Animated current flow and burnt-out parts when you overload them
- SPICE netlist import/export with .param and .subckt, SVG/PNG/CSV/BOM exports
- Free, no login, projects stay on your device
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Twinworks
Factory digital twin & production simulation
Model a production line, simulate it and find the bottleneck — free, in your browser.
- Draw a factory, press play, watch parts flow and the bottleneck light up
- Real statistics: warm-up, replications and confidence intervals
- OEE, Little’s law, state Gantt and cost per good part out of the box
- What-if scenarios, buffer sweeps and a buffer allocation optimiser
- Runs locally, saves to your browser — no account, no upload
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Flipline
Drawing, pixel art & animation
A few drawings. A little life. Make a flipbook in your browser.
- Local drawing and frame-by-frame animation
- Onion skins, layers, transform handles and automatic inbetweens
- GIF, video, PNG sequence, sprite sheet and storyboard exports
- Pixel art, sprites and seven tools for people and AI agents
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Lumina
Photo editor & image toolkit
Bring out what you saw. A free photo studio, right in your browser.
- Edit photos on your device, with no upload
- Reversible adjustments, color mixer, looks, on-photo crop and styled text
- JPEG, PNG and WebP exports, plus editable projects
- Thirteen related tools available through API and MCP
Topics & themes
Premium apps
Everyday life & money
- Everyday problem-solving9 tools
- Money-saving & comparison13 tools
- Home, travel & daily life10 tools
- Internet, AI & productivity8 tools
- Contracts, safety & accessibility6 tools
- Fun & games12 tools
- Everyday calculators7 tools
Developer & data
- Developer & data tools15 tools
- Charts & data5 tools
- Math & science10 tools
- Cryptography & security tools10 tools
Files, documents & media
Technical explorers
Missing a tool? Found a bug?
Every idea, bug report and piece of feedback is read and highly appreciated. It decides what we build and fix next.
Premium apps
Premium apps
Full, free software programs in your browser: CAD, robotics, electronics, embroidery and factory simulation. · 43 tools
3D Form Model Report & Export
Measure a form model by tag and export its geometry as OBJ or STL.
Animation Exposure Sheet
Turn drawing holds into a precise animation timing sheet.
Animation Motion Study Generator
Generate an editable flipbook to compare animation easing curves.
Color Harmony & Shift Generator
Build HSL harmonies with eased shifts, locked colors and reusable palette exports.
Footprint to 3D Solid Extruder
Turn a simple footprint into a closed 3D solid with OBJ, STL and editable geometry.
Image Grid Splitter
Slice a photo into numbered tiles without losing edge pixels.
Image Shape Mask & Feather
Clip a photo into a soft rectangle or ellipse with PNG transparency.
Kerfwise Cabinet Builder
Parametric cabinet → every part with cut sizes, edge banding, drilling and hardware.
Kerfwise CNC G-code Generator
Nest parts and get CNC router G-code: compensated profiles, tabs, ramps, drilling cycles, time.
Kerfwise Cut List & Cost
Cabinets or a Kerfwise project → cut list, edge banding, hardware, sheets and costs.
Kerfwise Sheet Nesting Optimizer
Nest rectangular and shaped parts on sheets: kerf, grain, yield, lower bound, offcuts, SVG + DXF.
Kinetica Collision Check
Robot pose + obstacles → collisions, minimum clearance and self-collision between links.
Kinetica Forward Kinematics
DH table or URDF + joint values → TCP pose, every joint frame, Jacobian and manipulability.
Kinetica Inverse Kinematics
Target TCP pose → all joint solutions found, residuals, joint limits and reachability.
Kinetica Trajectory Planner
Waypoints (PTP, LIN, CIRC) + limits → timed joint samples, cycle time and peak velocities.
Layer Blend Color Mixer
Preview eight blend modes and opacity for two opaque colors.
Layer Transform & Bounds Planner
Calculate a layer transform, rotated corners and canvas bounds.
Ohmforge AC Sweep (Bode plot)
Frequency response of a circuit: Bode magnitude/phase, −3 dB corner and unity gain.
Ohmforge DC Operating Point
SPICE netlist in, node voltages, branch currents, power and overload warnings out.
Ohmforge LED Resistor Calculator
Series resistor for LEDs, rounded to a standard value and checked with a real diode model.
Ohmforge Transient Simulation
Simulate a circuit over time: waveforms, Vpp/RMS/frequency, CSV and a chart.
Palette Contrast Matrix
Check every palette color pairing against WCAG text contrast thresholds.
Photo Collage & Image Joiner
Make a photo grid or join photos horizontally and vertically.
Photo Crop & Resize Planner
Plan a precise crop and output size before resizing a photo.
Photo Histogram & Clipping Analyzer
Inspect RGB histograms, clipped channels and tonal percentiles in a photo.
Photo Palette & Text Contrast
Check palette luminance and choose readable text for photos and graphics.
Photo Print Size Planner
Find how large your photo can print at your chosen resolution.
Photo to Animated GIF
Turn an ordered set of photos into a looping animated GIF.
Photo Tone Curves & Profile Processor
Apply levels, RGB curves and white balance, or reuse a Lumina photo profile.
Pixel Art Image Converter
Convert images into pixel art with palettes, dithering and retro effects.
Pixel Grid Transform
Flip, rotate or shift an indexed pixel sprite without blur.
Pixel Palette Format Converter
Convert HEX, GIMP GPL and JASC-PAL palettes without changing color order.
Retro Pixel Art Batch Processor
Apply one retro palette and effect recipe to a ZIP of images.
Sprite Sheet Layout Planner
Plan an animation atlas with exact frame rectangles and padding.
Threadsmith Design Stats
Stitch count, colours, trims, thread, sewing time and density of a DST, PES, JEF or EXP file.
Threadsmith Digitizer
Turn shapes, SVG paths, text or a whole project into embroidery stitches with stats and preview.
Threadsmith Stitch File Writer
Write DST, PES, JEF or EXP embroidery machine files from a stitch list or a Threadsmith project.
Twinworks Bottleneck Analysis
Find the constraint of a production line and test fixes: ranked bottlenecks with what-if gains.
Twinworks Buffer & Parameter Sweep
Sweep a buffer size (or any parameter) and get the throughput curve with confidence intervals.
Twinworks Buffer Allocation Optimiser
Distribute a fixed number of buffer places over a line for maximum throughput.
Twinworks Factory Simulation
Simulate a production line: throughput, lead time, WIP, OEE and the bottleneck, with CIs.
Twinworks Line Balancing
Assign assembly tasks to stations for a takt time: efficiency, balance delay and smoothness index.
Twinworks Queueing Check
M/M/1, M/M/c, M/D/1, M/G/1 and Kingman waiting times — optionally verified by simulation.
Everyday life & money
Everyday problem-solving
Decide, plan and sort out life admin with transparent calculations. · 9 tools
Cancellation Navigator
Verified steps to cancel Netflix, Spotify, Prime & more, plus a cancellation letter.
Deadline Decoder
Find every deadline, required action and consequence in a letter or notice.
Decision Simulator
Compare 2–6 choices by expected value, worst case, best case and minimax regret.
Form Translator
Plain-language help for confusing forms: field-by-field hints and jargon explained.
How Long Will It Last?
Estimate remaining life of appliances and home components and plan the replacement.
Is It Worth It?
Buy, rent, repair or subscribe? Compare total cost and NPV over the years you need it.
Life Admin Generator
A dated to-do list for moving, marriage, a baby, a new job and other life events.
Repair or Replace
Fix it or buy new? The 50% rule plus a cost-per-year check, with a clear verdict.
True Cost Calculator
What a car, pet, appliance, home or gadget really costs per year, month and day.
Money-saving & comparison
Compare prices, bills, salaries and subscriptions in real numbers. · 13 tools
Bill Detective
Spot spikes, price changes and calculation errors across your utility bills.
Break-even Explorer
When does an investment pay for itself? Payback, NPV and IRR for solar, EVs, heat pumps…
Bulk Buy Brain
Is the bulk pack really cheaper once waste, storage and tied-up cash are counted?
Currency Converter
Convert an amount into several currencies at ECB euro reference rates, with rate date and source.
Hidden Fee Finder
Paste a quote, contract or invoice and see every fee, tax, penalty and add-on.
Historical FX Chart
Chart exchange rates over time from ECB data: min, max, average, change, volatility and CSV export.
Inflation Time Machine
What was money from one year worth in another? CPI-based, 20 countries, World Bank data.
Multi-Currency Invoice Calculator
Convert invoice lines in different currencies at ECB reference rates, with VAT, rounding and totals.
Price Per Everything
Compare products by price per gram, use, serving, hour or year of life.
Salary Reality Check
Compare job offers by real net pay per hour, including commute time and living costs.
Subscription Stack
Add up every subscription, spot overlaps and see which ones to cancel and what you save.
Travel Exchange Fee Calculator
Compare what cards, ATMs, DCC and exchange bureaus really cost abroad vs the ECB reference rate.
Warranty Value Calculator
Is the extended warranty worth it? Expected payout vs. price and break-even failure rate.
Home, travel & daily life
Furniture, moving, travel connections, food and home maintenance. · 10 tools
Food Storage Guide
How long is food safe in the fridge or freezer? Dates from the official FoodSafety.gov chart.
Household Chore Rotator
Fair chore rotation by effort and availability, with per-person totals and a calendar.
Household Maintenance Calendar
A dated home maintenance schedule for your appliances and features, as a calendar file.
Jet Lag Planner
A day-by-day sleep, light and caffeine plan to beat jet lag, with calendar export.
Leftover Chef
Turn leftovers and fridge odds and ends into 5 recipe ideas, using what expires first.
Moving Box Planner
How many moving boxes, how much tape, which truck and when to start packing.
Room Layout Optimizer
Auto-arrange furniture in a room around doors, windows and a clear walkway.
Travel Connection Checker
Estimate your odds of making a flight connection, step by step.
Weekly Meal Planner
Turn your pantry and its expiry dates into a 7-day dinner plan and a shopping list.
Will It Fit?
Check if a sofa, wardrobe or box fits through doors, corners, stairs and lifts.
Internet, AI & productivity
Understand errors, policies, scams, screenshots and AI answers. · 8 tools
AI Answer Verifier
Split an AI answer into claims and see which ones your sources actually support.
Error Message Translator
Paste a technical error and get the plain-English cause and troubleshooting steps.
File Format Doctor
Find out what a file really is from its bytes, why it will not open and how to convert it.
Privacy Policy Decoder
What a privacy policy says it collects, shares, sells and keeps — with quoted evidence.
Prompt-to-Tool Router
Describe your problem in plain words and get the right tools and order to use them.
Scam Signal Checker
Check a message or link for common scam and phishing warning signs — without clicking.
Screenshot to Steps
Turn a screenshot of an app or website into numbered steps for what you want to do.
Website Change Explainer
Compare two versions of a page and see which changes matter: prices, terms, dates, links.
Contracts, safety & accessibility
Contracts, laws, compatibility, accessibility and preparedness. · 6 tools
Accessibility Fixer
Turn WCAG 2.2 problems in your HTML into concrete code fixes, grouped by effort.
Before You Sign
Spot risky contract clauses (renewal, notice, liability, non-compete…) before you sign.
Digital Estate Organizer
List your online accounts and get a prioritised plan for what happens to them – no passwords needed.
Disaster Prep Builder
Build an emergency supply list for your household from official Ready.gov or BBK guidance.
The Compatibility Engine
Will this charger, cable, version or PC part work together? Rule-based checks with margins.
What Changed in This Law?
Compare two versions of a law or regulation section by section, with changed numbers and deadlines.
Fun & games
Dice, random pickers, puzzles and party games with fair, transparent rules. · 12 tools
Chore Roulette
Spin a fair chore rota: random but balanced by effort, with a “not again” rule.
Elo/Glicko Rating Lab
Rate players from game results with Elo, Glicko-1 and Glicko-2; history chart and win odds.
Emoji Cipher Playground
Turn secret notes into emoji and back: substitution, Caesar shift and base-emoji.
Equation Art Studio
Turn math into art: parametric, polar, Lissajous, rose and spirograph curves.
Keyboard Heatmap Visualizer
Paste any text: see which keys and fingers do the work on QWERTY, Dvorak, Colemak & co.
Movie & Series Marathon Planner
Plan a binge: when each movie or episode starts and ends, total days, and a calendar.
Movie Night Consensus Picker
Everyone ranks the films, vetoes count: Borda, approval, runoff and Condorcet decide.
Padel & Pickleball Scheduler
Fair Americano or Mexicano doubles rounds with balanced sit-outs, scores and standings.
Password Entropy Race
Race 2–6 passwords or passphrases: entropy, pattern penalties and crack times.
Regex Golf Arena
Match the left list, avoid the right list — in as few characters as possible.
Sports What-If Simulator
Simulate a match or a small league with a Poisson goal model — and replay “what if”.
Tournament Bracket Maker
Single or double elimination or round robin: seeded brackets, byes, results and downloads.
Everyday calculators
Percentages, dates, units, tips and other quick sums, with the working shown. · 7 tools
Loan Amortization Calculator
Annuity, linear or interest-only loans: schedule, extra payments, fixed-rate balance, APR.
One-Rep-Max & Plate Loader
1RM from any set (7 formulas + average), % and RPE tables, and which plates to load.
Percentage & Ratio Calculator
X% of Y, % change, reverse %, percentage points, ratios and aspect ratios, with formulas.
Random Generator
Random numbers, dice, coins, list picks, shuffles, fair teams, dates, strings and UUIDs.
Running Pace & Splits
Pace, time or distance in km or miles, splits, race predictions, treadmill speed, laps.
Sports Travel-Fatigue Estimator
Travel distance, time-zone jumps, rest and back-to-backs per game as a fatigue score.
Tip & Bill Split Calculator
Tip, tax and who pays what: split a bill equally, by shares or by items, rounded up.
Developer & data
Developer & data tools
Deterministic helpers for developers, data and research. · 15 tools
HeaderLens
Is a website down? Multi-region status, redirects, TLS and security headers.
Accessibility Snapshot
Static WCAG 2.2 snapshot of a page: findings by severity, evidence and manual checks.
Browser Compatibility Checker
Which browsers support a CSS property, JS API or HTML element? MDN data + Baseline status.
CiteShape
Paste a DOI, ORCID iD, ISBN or arXiv ID: validated, resolved, and formatted as APA, BibTeX and RIS.
CyberChef-lite Pipeline
One-click decoding recipes: JWT, base64 → gunzip → JSON, double URL decode, hex dump.
DataFresh
Is this dataset or API still fresh? Newest record, update cadence check and schema drift.
FileFit
Can this app open, edit or convert that file format? Verified facts with sources.
LocaleKit Country Format Rules
Address form fields, postal-code regex, calling code and date formats for any country.
Network Speed Tester
Measure latency, jitter, download and upload speed between your browser and our server.
RuleDate Deadline Calculator
Business-day and deadline maths with public holidays and a step-by-step rule trace.
Safe Markdown Preview
Render Markdown with GFM tables and footnotes to sanitised HTML and see what was removed.
TimeFair Meeting Planner
Find fair meeting times across time zones, with DST-exact local times and rotation.
Unicode Inspector
Every code point with name, script and bytes, plus hidden characters and look-alikes.
UnitProof Unit Calculator
Unit maths you can audit: dimension check, exact factors and a full derivation tree.
Unix Permission Calculator
chmod calculator: octal ↔ rwx, setuid/sticky, u+x style changes, umask and ls -l.
Charts & data
Turn numbers and tables into accessible charts and clear summaries. · 5 tools
CSV/Excel Chart Studio
Turn CSV, TSV or Excel data into line, bar, pie, scatter or histogram charts with SVG/PNG export.
Diagram & Flowchart Maker
Write flowcharts, sequence diagrams and mind maps as text and get a laid-out SVG/PNG diagram.
Embeddable Chart Builder
Make a self-contained chart to embed anywhere: inline SVG, standalone HTML, accessible snippet.
Geo Data Visualizer
Map CSV coordinates or GeoJSON as points, proportional circles, hex-bin heatmaps or choropleths.
Time-Series Explorer
Resample, smooth and decompose date/value data: trend, R², seasonality, YoY change and anomalies.
Math & science
Equations, statistics, plots and physics with every step explained. · 10 tools
Big-O Crossover Calculator
When does c₁·n log n beat c₂·n²? Crossover points, log-log chart and run times.
Erasure-Coding Playground
Reed–Solomon over GF(256): encode data into k + m shards, lose some, rebuild it.
Floating-Point Explorer
See how IEEE-754 half/single/double store a number: bits, exact value, ULP, rounding error.
Graph Algorithm Visualizer
BFS, DFS, Dijkstra, Bellman–Ford, A*, MST, topological sort and SCCs on your edge list.
Graphing Calculator
Plot up to 6 functions or parametric curves with roots, extrema, intersections and SVG/PNG export.
Math Workbench
Simplify, factor, differentiate, integrate, solve, take limits, series and plots in one box.
Matrix & Linear Algebra Lab
Exact-fraction RREF with steps, determinant, inverse, null space, eigenvalues, LU/QR and Ax = b.
Number-Theory Lab
Primality, factorisation, gcd, modular arithmetic, CRT, φ, π(n), Collatz, continued fractions.
Probability & Statistics Studio
Distributions, descriptive stats, confidence intervals and t, chi-square and z tests with p-values.
Step-by-Step Equation Solver
Solve linear, quadratic, rational and radical equations or linear systems with every step shown.
Cryptography & security tools
Hashes, encodings, keys, passwords and certificates, computed locally where possible. · 10 tools
Crypto Kitchen
CyberChef-style recipes: chain encodings, compression, hashes, AES, JWT and more, step by step.
Hash & HMAC Calculator
MD5, SHA-2, SHA-3, BLAKE2, CRC32 and HMAC of text or files, with checksum compare.
Key Derivation Lab
Derive keys with PBKDF2, scrypt, Argon2id and HKDF; compare costs with OWASP advice.
Local File Encryption Studio
Encrypt and decrypt files with AES-256-GCM and a password, locally in your browser.
Password & Passphrase Generator
Strong random passwords and passphrases, made in your browser, with exact entropy.
Private Breach Checker
Check if a password appears in known breaches without revealing it (k-anonymity).
RSA/ECC Key Inspector
Inspect PEM, DER, JWK or OpenSSH keys: type, size, curve, fingerprints, thumbprint and weaknesses.
Shamir Secret Sharing
Split a secret into n shares so any k recover it, and combine shares, locally.
TLS Cipher-Suite Simulator
See which TLS version, cipher and group browsers, Android, Java and OpenSSL get from your server.
X.509 / ASN.1 Certificate Inspector
Decode X.509 certificates, chains and CSRs: SANs, usages, CT SCTs, chain order and an ASN.1 tree.
Files, documents & media
PDF & documents
Merge, split, compress, convert and inspect PDFs and office documents. · 7 tools
Office to PDF Converter
Convert Word, Excel, PowerPoint, OpenDocument, RTF and CSV files to PDF with LibreOffice.
PDF ↔ Image Converter
Turn PDF pages into PNG or JPG images, or combine images into a PDF without quality loss.
PDF Compressor
Make PDFs smaller with Ghostscript presets or custom image DPI and JPEG quality, with previews.
PDF Form & Signature Studio
List and fill PDF form fields, and place a visible signature image or typed name on a page.
PDF Merge, Split & Reorder
Merge PDFs, split by page count or ranges, and reorder, remove, rotate or duplicate pages.
Searchable PDF OCR
Make scanned PDFs searchable and copyable with OCRmyPDF and Tesseract, optionally as PDF/A.
Secure PDF Redactor
Black out names, numbers or areas in a PDF for real: the text is removed, not just covered.
Audio, video & images
Compress, convert, trim and inspect images, audio and video files. · 19 tools
Audio Cutter & Merger
Trim audio, keep or remove ranges, fade in/out, or join up to 10 clips with crossfades.
Audio Loudness Normalizer
Measure LUFS and true peak, then normalise to Spotify, podcast or EBU R 128 targets.
Background Remover
Remove plain backgrounds from product photos and logos (colour-based, no AI) → transparent PNG.
Batch Image Resizer & Cropper
Resize or crop up to 30 images at once: exact size, fit, percentage or 1:1, 4:5, 16:9, 9:16.
Batch Watermark Studio
Add a text or logo watermark to up to 30 images at once: position, tiling, opacity and angle.
EXIF Inspector & Cleaner
See all photo metadata (EXIF, GPS, XMP, IPTC, MakerNotes) and download a cleaned copy.
HEIC/RAW Image Converter
Convert iPhone HEIC, AVIF and camera RAW (CR2, CR3, NEF, ARW, DNG…) to JPG, PNG or WebP.
Image Compressor
Shrink JPG, PNG, WebP, AVIF or GIF images: convert, resize, strip metadata and compare sizes.
Image Upscaler
Enlarge images 2×, 3× or 4× with classic Lanczos/Mitchell filters and sharpening (no AI).
MP3 Tag & Cover Editor
Edit MP3 ID3 tags (title, artist, album, year…) and add, replace or remove the cover.
Subtitle Studio
Convert SRT, VTT, ASS and SBV; shift, re-sync, fix overlaps, wrap lines and check CPS.
SVG Optimizer
Shrink and sanitise SVG files: strip editor junk and scripts, round numbers, minify paths.
Universal Audio Converter
Convert MP3, WAV, FLAC, Ogg, Opus, M4A and AIFF with bitrate and sample-rate control.
Universal Video Converter
Convert video to MP4, WebM, MOV or MKV: resize, set quality and fps, or remux losslessly.
Vertical Video Reframer
Reframe video to 9:16, 1:1, 4:5 or 16:9 by cropping, a blurred background or bars.
Video Compressor
Shrink a video to a target size (two-pass) for e-mail, WhatsApp or Discord, or by quality.
Video Cutter & Merger
Trim video, remove a section or join clips: lossless copy or frame-exact re-encode.
Video to GIF Creator
Turn a video clip into a high-quality GIF or animated WebP with fps, width and dithering.
Video to MP3 Extractor
Extract a video’s soundtrack as MP3, WAV or FLAC, or copy the original audio losslessly.
Technical explorers
Blockchain & Web3 explorers
Transactions, contracts, bridges, permissions, MEV and governance, decoded from the chain. · 15 tools
Account Abstraction Explorer
Decode ERC-4337 bundles: UserOperations, paymasters, gas per op, deployed smart accounts.
Blockchain Incident Replay
Replay an exploit from tx hashes: ordered timeline, fund-flow graph and who profited.
Bridge Transfer Tracker
Where is my bridged money? Finds the bridge deposit in a transaction and checks if it arrived.
Cross-Chain Transaction Explorer
Follow one transaction across chains: source tx, bridge deposit and destination fill on a timeline.
DAO Governance Explorer
Snapshot proposals, vote concentration, Governor state and treasury balances in one view.
DeFi Liquidation Explorer
Recent Aave V3 liquidations in USD, who liquidated whom, and a live health-factor check.
Gas Fee Intelligence Explorer
Live gas on 7 EVM chains: base fee, tips, trend and the USD cost of transfers and swaps.
MEV Explorer
Who extracted value in this block? Sandwiches, arbitrage, liquidations, builder and tips.
Rollup Batch Explorer
How L2 transactions reach Ethereum: unsafe → safe → finalized, blobs, batch costs, withdrawal waits.
Smart Contract Relationship Graph
Map a contract's proxy, implementation, admin, owner, deployer/factory and token links as a graph.
Smart Contract Upgrade Explorer
Is this smart contract upgradeable, who controls upgrades, and what changed?
Stablecoin Flow Explorer
USDC/USDT supply per chain, recent mints, burns and whale transfers, cross-chain totals.
Token Unlock Explorer
Model token vesting (cliff, linear, monthly, tranches, TGE) or audit a VestingWallet.
Transaction Decoder
See what an EVM transaction actually did: call, events, token transfers, fee, finality.
Wallet Permission Explorer
Who can move your tokens? Allowances, Permit2, NFT operators and EIP-7702 delegation, with risk.
Internet infrastructure explorers
DNS, BGP, certificates, IPv6, CDNs, e-mail and outages: the plumbing of the internet. · 11 tools
ASN Relationship Explorer
An autonomous system at a glance: holder, country, BGP neighbours and announced prefixes.
BGP Route Explorer
Who announces an IP or prefix in BGP: origin ASes, RPKI validity, visibility and origin changes.
CDN Behaviour Explorer
Which CDN serves a URL, whether it caches it (HIT/MISS, Age, TTL) and how, from two requests.
Certificate Transparency Explorer
Every logged certificate for a domain: history, issuers, subdomains, wildcards and expiry.
DNS + Certificate Explorer
DNS records, e-mail security, CAA, live TLS certificate and CT history for a domain.
Domain History Graph
Registration, DNS, hosting networks, certificates and Wayback captures of a domain as a timeline.
E-mail Infrastructure Explorer
MX, SPF lookups, DMARC, DKIM, MTA-STS, TLS-RPT and BIMI for a domain, scored with fixes.
Global DNS Explorer
Ask every authoritative name server and public resolvers: records, propagation, DNSSEC, mistakes.
HTTP Technology Explorer
Headers, compression, caching, HTTP/2-3 hints, redirects, security and tech stack for a URL.
Internet Outage Atlas
Correlate public outage signals (IODA, RIPEstat BGP, live probe) for a country, ASN or domain.
IPv6 Readiness Explorer
Is a domain reachable over IPv6? Web, DNS and mail checks, address classes and a scored report.
Security & supply-chain explorers
Vulnerabilities, SBOMs, containers, provenance, OAuth scopes and advisories. · 13 tools
Artifact Provenance Explorer
Verify npm build provenance: Sigstore signature, transparency log, source repo and commit.
C2PA Credentials Inspector
Read C2PA Content Credentials in images and videos: actions, AI hints, signer and signature.
Container Image Explorer
Inspect a container image: platforms, layers, base image, root user, labels and cosign signature.
CVE Relationship Graph
One CVE or GHSA as a graph: aliases, affected packages, fixed versions, KEV status and EPSS.
Dependency Vulnerability Explorer
Known vulnerabilities in your dependencies, and the version that fixes each one.
OAuth Permission Explorer
What an OAuth consent request really allows: scopes, risky combinations and flow problems.
Open Source Trust Explorer
Is this open-source project maintained and trustworthy? Scorecard, activity and provenance.
Package Ecosystem Graph
Who depends on what: resolved dependency graph, duplicates and the blast radius of breaking changes.
Passkey & WebAuthn Tester
Test passkeys in your browser and decode WebAuthn responses: flags, AAGUID, signatures.
SBOM Explorer
Open a CycloneDX or SPDX SBOM: components, licences, dependency tree and known vulnerabilities.
SBOM License Checker
Check SBOM licences: SPDX expressions, copyleft class and conflicts with your project licence.
Security Advisory Timeline
Disclosures, affected ranges, fixes and withdrawals for a package on one timeline, with time-to-fix.
Security Configuration Scanner
Passive, graded check of a domain's TLS, security headers, DNS security and security.txt.
Developer & cloud explorers
APIs, Kubernetes, traces, query plans, Terraform, CI, serverless, lineage and cron. · 10 tools
API Explorer of Explorers
Search 2,500+ public APIs or summarise any OpenAPI spec: servers, auth, endpoints, changes.
CI/CD Failure Explorer
Paste CI logs from several runs: root cause per run, grouped signatures, top causes and fixes.
Cron Job Explorer
Paste a crontab or CronJob YAML: plain-English schedules, DST-exact next runs, herds and overlaps.
Data Lineage Explorer
Paste SQL or dbt models: table lineage graph, column lineage and upstream/downstream of any field.
Distributed Trace Explorer
Paste an OTLP, Jaeger or Zipkin trace: span tree, critical path, self-time, N+1 calls and errors.
Kubernetes Event Explorer
Paste kubectl events and get a timeline, reason taxonomy and likely root causes per workload.
OpenAPI Diff Explorer
Compare two versions of an OpenAPI spec and see exactly which changes break clients.
Query Plan Visualizer
PostgreSQL EXPLAIN (ANALYZE) or MySQL EXPLAIN JSON → plan tree, hot nodes and index suggestions.
Serverless Performance Explorer
Lambda REPORT lines → cold-start rate, p50/p95/p99, memory right-sizing and cost per 1M calls.
Terraform Plan & Drift Explorer
Paste terraform show -json: drift, replacement reasons, attribute diffs and risky deletes.
AI infrastructure & agent explorers
MCP servers, agent tools, traces, models, costs, RAG citations and structured output. · 10 tools
Agent Permission Graph
See what your AI agent can reach: MCP servers, commands, files, network and secrets – with risks.
AI Agent Tool Explorer
Index of tools AI agents can call: this site, the MCP Registry or your definitions, by capability.
AI Model Compatibility Explorer
Which LLMs take images, audio or files, fit your context and support tools or structured outputs?
AI Tool-Call Trace Explorer
Paste an agent transcript: see every tool call in order, with errors, timings, retries and loops.
AI Website Readiness Explorer
Can ChatGPT, Claude, Perplexity and AI agents read your website? Explainable score.
LLM Cost Explorer
Monthly LLM API cost per model for your workload, with prompt-caching and batch savings.
MCP Server Explorer
Inspect any MCP server before you connect an AI agent: tools, permissions, risks, changes over time.
Model Behavior Regression Explorer
Compare eval results of two model versions: accuracy, regressions, McNemar p-value, flaky items.
RAG Citation Debugger
Check a RAG answer's citations against the retrieved chunks: uncited claims, wrong sources, numbers.
Structured Output Validator
Validate AI JSON output against a JSON Schema: parse errors with line/column, plain-language fixes.
Public technical data explorers
Public spending, energy grids, satellite imagery, software adoption and web history. · 5 tools
Energy Grid Explorer
Generation mix, load, renewable share, cross-border flows and power prices for European grids.
Internet Archive Change Explorer
See how a web page changed in the Wayback Machine: capture timeline plus the changes that matter.
Public Spending Explorer
Search government contracts and grants: who pays whom, totals per agency and vendor.
Satellite Change Explorer
Compare NASA satellite images of any place on two dates: true colour, NDVI, night lights.
Software Adoption Explorer
Open-source usage signals: weekly downloads, growth and version adoption for npm, PyPI, crates.
Explorer of Everything
One search box across every explorer. · 1 tools
Explorer of Everything
Search transactions, contracts, domains, packages, advisories, MCP servers and websites in one box.
Workflows: tools that work together
Moving home
Personalised moving checklist with deadlines, box and van estimate, an optional "will the sofa fit?" check, and a maintenance calendar for the new place.
Is this message a scam?
Analyses a suspicious e-mail/SMS for scam signals, then checks the reachability and security headers of the linked website. Never claims a message is safe.
Subscription clean-up
Totals your subscriptions, flags overlaps and poor value, and gives verified cancellation steps for the one you want to cancel first.
Missing a tool? Found a bug?
Every idea, bug report and piece of feedback is read and highly appreciated. It decides what we build and fix next.