Definition
What is a free online tool?
A free online tool is a browser-accessible page that performs a short task: generate a value, validate a format, convert a file, compare content or calculate a result.
50 tools · 6 categories · 7 workflows
All free OnSubmit tools
A searchable catalog of online tools to generate, validate, convert, compare and calculate faster: test data, developer formats, PDFs, images, text, finance and QA workflows.
GeneratorsValidatorsConvertersCalculators
Why it matters
A catalog structured by intent
OnSubmit connects each tool to categories, entities, FAQs and complementary tools. This structure helps users choose the right tool and continue a workflow without starting over.
Categories
Explore by tool family
Each category has a dedicated page for tools in the same domain.
14 toolsDevelopmentFormat, validate, generate and inspect JSON, tokens, hashes and technical data for development and QA workflows.UUID Generator · Password Generator · URL Encoder / Decoder · JSON Formatter12 toolsFinanceCalculate loans, VAT and salaries or validate French business identifiers and banking test data.Loan Calculator · French Notary Fees Calculator · VAT Calculator · Gross Net Salary Calculator11 toolsUtilitiesPractical browser tools for production, QA, test data, time zones, colors and everyday tasks.Wi-Fi QR Code Generator · vCard QR Code Generator · QR Code Reader · QR Code Tester6 toolsImagesPrepare, compress, convert and share HEIC, JPG, PNG and QR code images directly in the browser.QR Code Generator · HEIC to JPG · Image Compressor · PNG to JPG Converter4 toolsTextTransform, compare, count and convert text, Markdown or Base64 content for writing, documentation and QA.Base64 Encoder / Decoder · Markdown to HTML · Lorem Ipsum Generator · Online Diff Checker3 toolsPDFCreate, merge or convert PDF files from images directly in the browser for scans, forms and documents.Merge PDF · Image to PDF · Split PDF
Catalog
Search all tools
Filter by name, need, format, category, keyword or business entity.
50 result(s)
UUID GeneratorGenerate UUID v4 identifiers for databases, APIs, fixtures and distributed systems.Open toolPassword GeneratorCreate strong random passwords with configurable length, letters, numbers and symbols.Open toolURL Encoder / DecoderEncode or decode URLs, query strings and percent-encoded text.Open toolJSON FormatterFormat, indent and validate JSON, XML or SQL snippets for debugging and documentation.Open toolRegex TesterTest JavaScript regular expressions, flags, matches and replacements.Open toolJWT Decoder / EncoderDecode, inspect and regenerate test JSON Web Tokens with HS256.Open toolCron Expression ParserParse a cron expression and preview upcoming run times.Open toolMD5 Hash GeneratorCalculate and compare the MD5 digest of UTF-8 text or local files for checksums, compatibility and legacy workflows.Open toolTimestamp ConverterConvert Unix timestamps to readable dates and dates back to Unix time.Open toolBase64 Encoder / DecoderEncode text to Base64 and decode Base64 back to readable text.Open toolMarkdown to HTMLConvert Markdown to readable HTML with a live preview.Open toolLorem Ipsum GeneratorGenerate placeholder text for wireframes, prototypes, templates and layout tests.Open toolOnline Diff CheckerCompare two texts, JSON snippets or code blocks by line, word or character and highlight aligned additions and removals.Open toolQR Code GeneratorCreate static QR codes for URLs, text, Wi-Fi, vCard, email, phone and SMS, then export PNG or SVG.Open toolWi-Fi QR Code GeneratorCreate a Wi-Fi QR code for a network name, password, security type and hidden SSID.Open toolvCard QR Code GeneratorCreate a contact QR code with name, phone, email, company, website and postal address.Open toolQR Code ReaderRead a QR code from an image or camera and inspect its exact content locally.Open toolQR Code TesterTest whether a QR code decodes and inspect URL security signals before printing or opening it.Open toolHEIC to JPGConvert up to 10 HEIC or HEIF photos to JPG locally for iPhone compatibility, web uploads and sharing.Open toolImage CompressorReduce JPG or PNG file size and adjust image width before publishing or sharing.Open toolMerge PDFMerge multiple PDF files into a single document.Open toolImage to PDFConvert one or more JPG or PNG images into a PDF document.Open toolWord CounterCount words, characters, sentences, reading time and term density in a text.Open toolTimezone ConverterCompare a date and time across Paris, London, New York, San Francisco, Tokyo, Sydney and UTC.Open toolColor ConverterConvert colors between HEX, RGB and HSL with a visual preview.Open toolLoan CalculatorEstimate loan payments, insurance, interest and financing cost from project amount, down payment, rate and duration.Open toolFrench Notary Fees CalculatorEstimate notary fees for a property purchase in France, old or new.Open toolVAT CalculatorConvert net price to gross price, calculate VAT or recover net price from gross.Open toolGross Net Salary CalculatorEstimate net salary from gross salary, and gross from net, for French salary scenarios.Open toolIBAN & BIC ValidatorValidate IBAN and BIC format, country length and checksum structure.Open toolIBAN & BIC GeneratorGenerate fictitious IBAN and BIC values by country for banking forms, QA, mockups and fixtures.Open toolTest Credit Card GeneratorGenerate fictitious credit card numbers for form tests using Luhn-compatible values.Open toolFrench SIRET / SIREN GeneratorGenerate fictitious French SIREN and SIRET numbers with valid control keys for tests.Open toolSIRET / SIREN ValidatorValidate the length, structure and Luhn key of French SIREN or SIRET numbers.Open toolFrench VAT Generator & ValidatorGenerate a French VAT number from a valid SIREN or SIRET, then check its local format and key.Open toolFrance Fake Address GeneratorGenerate coherent synthetic French addresses locally for forms, CRM, checkout and repeatable QA datasets.Open toolFake Identity GeneratorGenerate fictitious user profiles for form tests, prototypes, QA and mockups.Open toolFake French Company GeneratorGenerate coherent synthetic French company data with SIREN, SIRET, VAT, address, contact, IBAN/BIC and UUID.Open toolCSV JSON ConverterConvert CSV to JSON and JSON back to CSV directly in the browser.Open toolJSON to TypeScriptGenerate TypeScript interfaces from a representative JSON example.Open toolYAML JSON ConverterConvert YAML to JSON and JSON back to YAML for configuration and API workflows.Open toolSHA256 / SHA512 GeneratorCalculate SHA-256, SHA-384 and SHA-512 hashes for text.Open toolWorld Stock Market HoursTrack regular sessions, breaks, holidays and upcoming events across eight major world exchanges.Open toolLive World ClockDisplay five to ten large world clocks at once in a customizable full-screen board.Open tool.env Example GeneratorTurn a .env file into a safe .env.example without exposing secrets.Open toolSplit PDFExtract selected PDF pages into one document or create one PDF file per selected page.Open toolPNG to JPG ConverterConvert up to 20 PNG images to JPG with adjustable quality and a chosen transparency background.Open toolJPG to PNG ConverterConvert up to 20 JPG or JPEG images to PNG locally in the browser.Open toolImage to WebP ConverterConvert up to 20 PNG or JPG images to WebP with adjustable output quality.Open toolDate Duration CalculatorCalculate exact days, weeks, months and years between two dates, or add and subtract date units.Open tool
Guided workflows
Find the right workflow
These pages group several tools around a concrete need.
8 toolsTest dataGenerate identifiers, fake profiles, addresses, banking details and company data to test interfaces without using real personal data.6 toolsBanking test dataPrepare fictitious banking values to test SEPA forms, IBAN/BIC fields, French RIB details, payment methods and billing workflows.7 toolsBusiness invoicingGroup the tools needed to prepare invoice tests, check French company identifiers, calculate VAT and validate French VAT number structure.6 toolsFinance calculatorsEstimate loan payments, VAT, gross/net amounts, salary and French notary fees for invoices, purchases and budget scenarios.7 toolsData convertersConvert, format and compare structured data for APIs, exports, configuration files, documentation and developer integrations.6 toolsSecurity and hashGenerate passwords, calculate SHA hashes, inspect JWTs and prepare .env.example files without exposing production secrets.5 toolsQR codesCreate QR codes for URLs, text, Wi-Fi, vCard, email, phone and SMS, then read or test their content directly in your browser.
Comparison
Which workflow should you use?
| Need | Recommended page | Related tools |
|---|---|---|
| Generate test data | Test data | UUID, fake identity, fake address, SIRET, IBAN/BIC |
| Test a banking form | Banking test data | IBAN/BIC, RIB, card number, fake identity |
| Convert API data | Data converters | JSON, CSV JSON, YAML JSON, TypeScript, Base64 |
| Prepare invoice or B2B tests | Business invoicing | VAT, SIRET/SIREN, IBAN/BIC, amounts |
| Check secrets, tokens and hashes | Security and hash | Password, SHA256, MD5, JWT, .env example |
Result scope
Understand what each type of tool does
The tool type defines the result scope: generation creates a synthetic value, validation checks local rules, conversion transforms the input and calculation applies displayed assumptions.
- A value with a valid format is not necessarily assigned or active in an official registry.
- Generated data is intended for tests, fixtures, demos and mockups.
- Calculators provide estimates from the rates, units and assumptions displayed.
FAQ
Frequently asked questions about OnSubmit tools
What free tools are available on OnSubmit?
OnSubmit groups generators, validators, converters and calculators for development, test data, PDFs, images, text and finance workflows.
How do I choose the right online tool?
Search by need: generate test data, validate a format, convert a file, compare text or calculate an amount.
Are OnSubmit results official verifications?
No, unless explicitly stated. Validators mainly check format, length or checksum; existence and status must be confirmed with the relevant bank, registry or authority.
Which tools help prepare test data?
Combine UUID, fake identity, fake address, fake SIRET/SIREN, test IBAN/BIC, test credit card and CSV JSON converter.
Which tools are useful for developers?
Common developer workflows use JSON Formatter, CSV JSON, YAML JSON, JSON to TypeScript, Base64, URL encoder decoder, Regex, JWT, cron and timestamp tools.