Guides
Short, practical guides on the things our tools help with — invoices, contracts, passwords and more. No fluff, and a free tool at the end of each.
How to make an invoice (free template)A simple guide to creating a professional invoice — what to include, how to number it, and how to get paid faster. Free invoice generator included.Read guide →Mutual vs unilateral NDA: what's the difference?Mutual (two-way) vs unilateral (one-way) NDA — the real differences, when to use each, mNDA vs NDA, and a free generator to make one in a minute.Read guide →What is a unilateral NDA?A unilateral (one-way) NDA explained — what it is, how it works, when to use one, whether it's enforceable, and how to create one free.Read guide →What is a mutual NDA?A mutual (bilateral) NDA explained — what it is, when both sides share, how it differs from a one-way NDA, and how to create one free.Read guide →How to create a strong passwordWhat actually makes a password strong — length, randomness and entropy — plus the common mistakes to avoid and a free generator.Read guide →Freelance and self-employed tax, explainedHow freelancers and the self-employed estimate tax and take-home pay — what's taxed, common regimes, and a free calculator.Read guide →How to write a quote clients say yes toWhat a good quote (estimate) includes, how to price and present it, and how to win the work — plus a free quote generator.Read guide →What is a JWT? A plain-English guideWhat a JSON Web Token is, how its three parts work, when to use one, and a free decoder to inspect any token.Read guide →What is hashing? SHA-256 in plain EnglishHow a hash function works — one-way, fixed-length and deterministic — what SHA-256 is for, and a free tool to hash any text.Read guide →What is a cron expression? A plain-English guideHow the five cron fields work — with ranges, lists and steps — how to read a schedule, and a free parser that shows the next run times.Read guide →What is a UTM parameter? A marketer's guideWhat UTM parameters are, what each of the five does, naming conventions that keep reports clean, and a free UTM link builder.Read guide →What is compound interest? A plain-English guideHow compound interest works, why it beats simple interest, the formula, and how compounding frequency and regular deposits grow your money — with a free calculator.Read guide →How to calculate rental yield (gross vs net)What rental yield is, how to work out gross and net yield, what counts as a good yield, and a free calculator to check any property.Read guide →What is unit economics? A seller's guideUnit economics explained for marketplace sellers — profit per unit, margin, break-even price, and a free calculator to model it.Read guide →Marketplace unit economics: Ozon, Wildberries & Yandex MarketHow to calculate unit economics for a marketplace seller — commission, fulfillment, returns and promo, with a worked example and a free calculator.Read guide →FBO vs FBS: which marketplace fulfillment model costs you lessFBO, FBS and realFBS compared for Ozon, Wildberries and Yandex Market sellers — who stores the stock, which fees each model charges, and how to pick by the numbers.Read guide →How to calculate VAT (add and remove)How VAT works, how to add VAT to a net price and remove it from a gross one, the formulas, and a free VAT calculator.Read guide →Is margin calculated with or without VAT?Margin is calculated on prices without VAT. Why VAT is not your money, when the gross shortcut still works, and where mixing gross and net inflates your margin.Read guide →How to set your hourly rate as a freelancerWork out a freelance hourly rate from the income you want to keep — the formula, realistic billable hours, tax and expenses, and when to raise it.Read guide →Marketplace seller taxes in 2026: УСН, АУСН or НПДWhich tax regime a Russian marketplace seller should choose in 2026 — УСН, АУСН or НПД. Rates, limits, the 2026 VAT change and the mistakes that cost money. Free calculator included.Read guide →