Clear, practical guides to the tools on Monu Tools. No fluff, just the parts that get you unblocked.
JSON is everywhere, in API responses, config files, and log lines, and almost all of it needs the same handful of fixes: make it readable, shrink it, convert it, or work out why a parser is choking on it. These guides walk through each job with real examples, and every one links to a tool that does the work right in your browser, so your data never leaves the page.
Why Is My JSON Invalid? How to Find and Fix the Error
The six mistakes that break JSON, how to read a parser error, and how to fix invalid JSON fast.
Pretty-Print vs Minify: When to Format JSON and When to Compress It
When to format JSON for readable diffs and debugging, when to minify it for size, and how to do both privately in your browser.
How to Convert JSON to CSV (and Keep Nested Data Sane)
Convert JSON to CSV without losing your nested objects: flattening, exploding arrays, delimiters, Excel BOM gotchas, and the round-trip back.
Turn a JSON Response into a TypeScript Interface in Seconds
Generate a TypeScript interface from any JSON response: optional fields, nullables, nested types, and where a single sample falls short.
YAML vs JSON: Which One Should Your Config Use?
YAML vs JSON compared for config files and APIs: syntax, comments, the Norway problem, indentation traps, TOML, and lossless conversion.
How to Minify JSON to Shrink API Payloads
What minifying JSON actually removes, the realistic 20 to 40 percent size win, and why server compression usually matters more.
How much protein you really need, how many calories your body burns, and what BMI does and does not tell you: these guides turn the numbers behind the calculators into plain, evidence-based answers. Every figure is sourced from research and health bodies, and each guide links the tool so you can run your own numbers.
How Much Protein Do You Need Per Day?
Work out how much protein per day you need from your bodyweight and activity level, with the official RDA, athlete ranges, and a worked example.
Protein Per Kg of Body Weight: What the Ranges Really Mean
Protein per kg of body weight, explained: the 0.8 to 2.2 g/kg ranges, who each fits, total vs lean mass, plus worked examples at 60, 80 and 100 kg.
How Much Protein to Build Muscle?
Protein for muscle gain explained: aim for 1.6 to 2.2 g/kg, why total intake wins, how to split meals, and why you also need a surplus and training.
How Much Protein Should You Eat to Lose Weight?
How much protein to lose weight: why a higher target of 1.6 to 2.4 g/kg in a deficit protects muscle, curbs hunger, and burns more energy.
How Many Calories Do You Need? BMR and TDEE Explained
Learn how a calorie calculator estimates your daily needs using the Mifflin-St Jeor BMR formula, activity multipliers, and TDEE, with a worked example.
BMR and TDEE: How Many Calories You Burn
What is BMR and TDEE? Learn how your body burns calories at rest, the three formulas, the activity factors, and how accurate the numbers really are.
What Is a Healthy BMI (and What It Misses)
What is a healthy BMI? See the formula, the WHO categories, a worked example, and the real limits of BMI as a health screening tool.
BMI vs Body Fat Percentage: Which Matters
BMI vs body fat percentage: what each number really measures, why they disagree, how to measure body fat at home, and healthy ranges by sex.
How income tax, VAT, and salaries work in France: the 2026 barème, the quotient familial and parts, the plafonnement and the décote, the four TVA rates, and a step-by-step guide to payslip deductions, in plain English. Every figure follows the official rates, and every guide links the calculator so you can run your own numbers.
How French Income Tax Works in 2026 (Barème, Parts, Décote)
A plain-English guide to French income tax on 2025 income: the 2026 barème, the quotient familial, the plafonnement and the décote, with a worked example.
How French VAT (TVA) Works: Rates, HT vs TTC, and a Worked Example (2026)
The four French TVA rates for 2026, what HT and TTC mean, a worked calculation example, and which rate applies to which goods.
How French Loans and Mortgages Work: Monthly Payment, TAEG, and Insurance (2026)
How the annuity formula works for French pret immobilier, what the TAEG includes, and how assurance emprunteur adds to your monthly cost. With a worked example.
French Gross to Net Salary: How the Deductions Work in 2026
A plain-English guide to French payslip deductions in 2026: vieillesse, Agirc-Arrco, CSG/CRDS, and a worked 3,000 EUR example.
How the French State Pension Is Calculated: SAM, Taux Plein, and Decote (2026)
How the French regime general base pension is calculated: SAM, the PASS ceiling, the 50% taux plein, the 1.25% decote per missing quarter, and worked examples.
How income tax, VAT, and severance pay work in Spain: the six IRPF brackets, the combined estatal and autonomica scale, the minimo personal allowance, the three IVA rates, and the 33-day and 20-day dismissal formulas. Every figure follows the official 2026 rates, and each guide links the calculator so you can run your own numbers.
How Spanish Income Tax (IRPF) Works in 2026
A plain-English guide to Spanish IRPF: the 6-bracket 2026 scale, the minimo personal method, tipo medio vs marginal, with a worked example.
How Spanish VAT (IVA) Works: Rates, Base Imponible, and a Worked Example (2026)
The three Spanish IVA rates for 2026, what base imponible means, how to add and remove IVA, and which rate applies to which goods and services.
Spanish Severance Pay: How Indemnizacion por Despido Is Calculated (2026)
Spanish severance pay: the 33-day and 20-day rules, monthly salary cap, a worked example at 2,000 EUR over 10 years, and the pre-2012 transition rule.
Spanish Net Salary: How Much of Your Gross Do You Keep in 2026?
How Spain's gross-to-net salary works in 2026: Seguridad Social (6.5 %), IRPF retention, 12 vs 14 pagas, and a worked example at 30,000 EUR gross.
How IRPEF works in Italy, how to calculate your net salary from RAL, how the Italian university grading system converts trentesimi into a voto di laurea on the 110 scale, and how the TFR severance fund compounds through yearly rivalutazione: clear guides with worked examples. Every figure follows official sources, and each guide links the calculator so you can run your own numbers.
How Italian Income Tax (IRPEF) Works in 2026
Plain-English guide to Italian IRPEF 2026: three-bracket scale, detrazione lavoro dipendente, IRPEF lorda vs netta, worked example at 30,000 EUR.
Italian Net Salary: How Much of Your RAL Do You Take Home in 2026?
Italian gross-to-net salary 2026: INPS (9.19 %), IRPEF on the imponibile, addizionali, tredicesima, and a worked example at RAL 30,000 EUR.
Italian University Grading Explained: From Trentesimi to 110 e Lode
How Italian exam grades in trentesimi convert to a voto di laurea on the 110 scale: media ponderata, thesis points, 110 e lode, ECTS and GPA.
How Italian VAT (IVA) Works: Rates, Imponibile, and Scorporo (2026)
The four Italian IVA rates for 2026, what imponibile means, how to add and remove IVA (scorporo), and which rate applies to which goods and services.
Italian TFR (Severance Fund) Explained: Formula, Rivalutazione, and Tax (2026)
How Italy's TFR severance fund works: the RAL / 13.5 quota, yearly rivalutazione, TFR in azienda vs fondo pensione, and how it is taxed at liquidation.
How net pay, tax, VAT and severance work in the Netherlands: the 2026 Box 1 brackets and the algemene heffingskorting and arbeidskorting credits, the 30%-ruling for incoming workers, the 8% vakantiegeld holiday allowance, the 21% and 9% BTW rates, and the statutory transitievergoeding. Every figure follows the official 2026 rates, and each guide links the calculator so you can run your own numbers.
How Dutch Net Salary Works in 2026 (Box 1, Heffingskortingen, 30%-Ruling)
Plain-English guide to Dutch net salary in 2026: the Box 1 brackets, the heffingskortingen, the 30%-ruling, and a worked example at 50,000 EUR gross.
How Dutch VAT (BTW) Works in 2026: 21% and 9% Rates Explained
Plain-English guide to Dutch BTW in 2026: the 21% and 9% rates, what each covers, the 2026 hotel change, and how to extract BTW from a gross price.
Dutch Holiday Allowance (Vakantiegeld) Explained for 2026
How Dutch vakantiegeld works in 2026: the 8% holiday allowance, the June to May reservation period, the May payout, and why the net is below 8%.
Dutch Severance Pay (Transitievergoeding) Explained for 2026
How the Dutch transitievergoeding works in 2026: the 1/3-month-per-year formula, exact pro-rata, the 102,000 EUR cap, and when severance is owed.
How take-home pay, tax, VAT and redundancy work in the UK for 2025/26: income tax for England, Wales and Northern Ireland and the separate Scottish bands, the Personal Allowance and its 100k taper, employee National Insurance, student loan repayments, the 20% and 5% VAT rates, and statutory redundancy pay. Every figure follows the official HMRC rates, and each guide links the calculator so you can run your own numbers.
How UK Take-Home Pay Works in 2025/26 (Income Tax, NI, the 100k Trap)
Plain guide to UK take-home pay for 2025/26: income tax bands, the 100k taper, National Insurance, student loans, and a worked example at 35,000 GBP gross.
How UK VAT Works: the 20%, 5% and 0% Rates Explained
Plain guide to UK VAT: the 20%, 5% and 0% rates, what each covers, how zero-rated differs from exempt, and removing VAT from a gross price.
UK Statutory Redundancy Pay Explained (2025/26)
How statutory redundancy pay works in 2025/26: who qualifies, the age-banded formula, the 20-year and 719 GBP caps, the 21,570 GBP max, and a worked example.
How your US paycheck and sales tax work for 2025: federal income tax brackets and the standard deduction, Social Security and Medicare (FICA) including the Additional Medicare Tax, and how sales tax is added at the state and local level. Federal figures follow the IRS and SSA, and each guide links the calculator so you can run your own numbers. State income tax is not included.
How Your US Paycheck Works in 2025 (Federal Tax, FICA, Take-Home)
Plain guide to US take-home pay for 2025: federal tax brackets, the standard deduction, Social Security and Medicare, and a worked example at 60,000 gross.
How US Sales Tax Works in 2025 (Add It, Reverse It, By State)
Plain guide to US sales tax: why there is no national rate, how state and local rates combine, and how to add tax to a price or reverse it out of a total.
Base64, URL encoding, JWTs, and hashing turn up in every web stack, and the same misunderstandings turn up with them: that encoding is encryption, that decoding a token verifies it, that a hash can be reversed. These guides clear that up with plain explanations and worked examples, and each one links a tool that does the job right in your browser, so your data never leaves the page.
Base64 Explained: Why Encoding Is Not Encryption
What Base64 actually does, why it makes data about a third larger, when to use it, and why it protects nothing on its own.
URL Encoding Explained: When and Why to Percent-Encode
Why URLs use %20 and other percent codes, which characters are safe, and when to reach for encodeURIComponent instead of encodeURI.
How to Read a JWT, and Why Decoding Is Not Verifying
A JWT is three Base64url parts anyone can read. Learn how to decode one, what each part means, and why decoding proves nothing.
Hashing vs Encryption: What a Hash Can and Cannot Do
Hashing is one-way and keyless; encryption is two-way and needs a key. Learn the difference, why you cannot decrypt a hash, and when to use each.
How Passwords Should Be Stored: Salting, bcrypt, and Why Not SHA-256
Why a fast hash like SHA-256 is wrong for passwords, what a salt does, and why bcrypt, scrypt, and Argon2 are the right tools.
How Webhook Signatures Work: HMAC, Shared Secrets, and Timing-Safe Checks
How Stripe and GitHub prove a webhook is genuine using HMAC and a shared secret, and the timing-safe comparison most developers get wrong.
UUIDv4 vs UUIDv7: Why Time-Ordered IDs Make Better Database Keys
UUIDv4 is random and scatters database indexes; UUIDv7 is time-ordered and inserts in order. Learn the difference and when each one wins.
Data URIs: Embedding Images with Base64, and When It Backfires
Inlining an image as a Base64 data URI removes a request but breaks caching and adds 33% size. Learn the size rules and the better SVG trick.
Regular expressions look cryptic until you learn the handful of pieces they are built from. These guides cover the core syntax, capturing and named groups, lookahead and lookbehind, the greedy-versus-lazy distinction and the catastrophic backtracking to avoid, and why a giant email regex is the wrong tool. Every guide links the regex tester so you can try each pattern in your browser, where your text never leaves the page.
Regex Basics: Characters, Classes, Anchors, and Quantifiers
The core building blocks of regular expressions: literal characters, character classes, anchors, quantifiers, and the flags that change everything.
Capturing Groups, Named Groups, and Backreferences
How parentheses capture parts of a match, how to name them, how backreferences match repeated text, and how to use all three when replacing.
Lookahead and Lookbehind: Matching by Context
Lookarounds check what surrounds a position without consuming it. Learn positive and negative lookahead and lookbehind with practical examples.
Greedy, Lazy, and Catastrophic Backtracking
Why quantifiers grab as much as they can, how lazy matching reins them in, and how nested quantifiers cause the ReDoS slowdown to avoid.
Why You Should Not Validate Email With a Giant Regex
The full RFC email regex is thousands of characters, rejects valid addresses, accepts dead ones, and risks ReDoS. Here is what to do instead.
Images are usually the heaviest thing on a page, and a few decisions, the right format, the right size, sensible compression, decide whether they load fast or drag everything down. These guides cover choosing between JPEG, PNG, WebP and AVIF, compressing without visible loss, converting iPhone HEIC photos, stripping hidden EXIF location data, resizing properly (and the DPI myth), and SVG versus PNG. Each links a tool that does the job right in your browser, so your images never leave the page.
Image Formats for the Web: JPEG, PNG, WebP, and AVIF
What sets JPEG, PNG, WebP, and AVIF apart, how much smaller the modern formats are, and a simple rule for which one to use.
How to Compress Images Without Losing Quality
What image compression really trades away, where the quality sweet spot is, and the steps that shrink a file without a visible drop.