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.
43 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 tools Development Format, validate, generate and inspect JSON, tokens, hashes and technical data for development and QA workflows. UUID Generator · Password Generator · URL Encoder / Decoder · JSON Formatter 11 tools Finance Calculate loans, VAT and salaries or validate French business identifiers and banking test data. Loan Calculator · French Notary Fees Calculator · VAT Calculator · Gross Net Salary Calculator 9 tools Utilities Practical 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 Tester 4 tools Text Transform, 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 Checker 3 tools Images Prepare, compress, convert and share HEIC, JPG, PNG and QR code images directly in the browser. QR Code Generator · HEIC to JPG · Image Compressor 2 tools PDF Create, merge or convert PDF files from images directly in the browser for scans, forms and documents. Merge PDF · Image to PDF
Catalog
Search all tools
Filter by name, need, format, category, keyword or business entity.
43 result(s)
UUID Generator Generate UUID v4 identifiers for databases, APIs, fixtures and distributed systems. Open tool Password Generator Create strong random passwords with configurable length, letters, numbers and symbols. Open tool URL Encoder / Decoder Encode or decode URLs, query strings and percent-encoded text. Open tool JSON Formatter Format, indent and validate JSON, XML or SQL snippets for debugging and documentation. Open tool Regex Tester Test JavaScript regular expressions, flags, matches and replacements. Open tool JWT Decoder / Encoder Decode, inspect and regenerate test JSON Web Tokens with HS256. Open tool Cron Expression Parser Parse a cron expression and preview upcoming run times. Open tool MD5 Hash Generator Calculate and compare the MD5 digest of UTF-8 text or local files for checksums, compatibility and legacy workflows. Open tool Timestamp Converter Convert Unix timestamps to readable dates and dates back to Unix time. Open tool Base64 Encoder / Decoder Encode text to Base64 and decode Base64 back to readable text. Open tool Markdown to HTML Convert Markdown to readable HTML with a live preview. Open tool Lorem Ipsum Generator Generate placeholder text for wireframes, prototypes, templates and layout tests. Open tool Online Diff Checker Compare two texts, JSON snippets or code blocks by line, word or character and highlight aligned additions and removals. Open tool QR Code Generator Create static QR codes for URLs, text, Wi-Fi, vCard, email, phone and SMS, then export PNG or SVG. Open tool Wi-Fi QR Code Generator Create a Wi-Fi QR code for a network name, password, security type and hidden SSID. Open tool vCard QR Code Generator Create a contact QR code with name, phone, email, company, website and postal address. Open tool QR Code Reader Read a QR code from an image or camera and inspect its exact content locally. Open tool QR Code Tester Test whether a QR code decodes and inspect URL security signals before printing or opening it. Open tool HEIC to JPG Convert HEIC or HEIF photos to JPG for wider compatibility. Open tool Image Compressor Reduce JPG or PNG file size and adjust image width before publishing or sharing. Open tool Merge PDF Merge multiple PDF files into a single document. Open tool Image to PDF Convert one or more JPG or PNG images into a PDF document. Open tool Word Counter Count words, characters, sentences, reading time and term density in a text. Open tool Timezone Converter Compare a date and time across Paris, London, New York, San Francisco, Tokyo, Sydney and UTC. Open tool Color Converter Convert colors between HEX, RGB and HSL with a visual preview. Open tool Loan Calculator Estimate loan payments, insurance, interest and financing cost from project amount, down payment, rate and duration. Open tool French Notary Fees Calculator Estimate notary fees for a property purchase in France, old or new. Open tool VAT Calculator Convert net price to gross price, calculate VAT or recover net price from gross. Open tool Gross Net Salary Calculator Estimate net salary from gross salary, and gross from net, for French salary scenarios. Open tool IBAN & BIC Validator Validate IBAN and BIC format, country length and checksum structure. Open tool IBAN & BIC Generator Generate fictitious IBAN and BIC values by country for banking forms, QA, mockups and fixtures. Open tool Test Credit Card Generator Generate fictitious credit card numbers for form tests using Luhn-compatible values. Open tool French SIRET / SIREN Generator Generate fictitious French SIREN and SIRET numbers with valid control keys for tests. Open tool SIRET / SIREN Validator Validate the length, structure and Luhn key of French SIREN or SIRET numbers. Open tool French VAT Generator & Validator Generate a French VAT number from a valid SIREN or SIRET, then check its local format and key. Open tool France Fake Address Generator Generate coherent synthetic French addresses locally for forms, CRM, checkout and repeatable QA datasets. Open tool Fake Identity Generator Generate fictitious user profiles for form tests, prototypes, QA and mockups. Open tool Fake French Company Generator Generate coherent synthetic French company data with SIREN, SIRET, VAT, address, contact, IBAN/BIC and UUID. Open tool CSV JSON Converter Convert CSV to JSON and JSON back to CSV directly in the browser. Open tool JSON to TypeScript Generate TypeScript interfaces from a representative JSON example. Open tool YAML JSON Converter Convert YAML to JSON and JSON back to YAML for configuration and API workflows. Open tool SHA256 / SHA512 Generator Calculate SHA-256, SHA-384 and SHA-512 hashes for text. Open tool .env Example Generator Turn a .env file into a safe .env.example without exposing secrets. Open tool
Guided workflows
Find the right workflow
These pages group several tools around a concrete need.
8 tools Test data Generate identifiers, fake profiles, addresses, banking details and company data to test interfaces without using real personal data. 6 tools Banking test data Prepare fictitious banking values to test SEPA forms, IBAN/BIC fields, French RIB details, payment methods and billing workflows. 7 tools Business invoicing Group the tools needed to prepare invoice tests, check French company identifiers, calculate VAT and validate French VAT number structure. 6 tools Finance calculators Estimate loan payments, VAT, gross/net amounts, salary and French notary fees for invoices, purchases and budget scenarios. 7 tools Data converters Convert, format and compare structured data for APIs, exports, configuration files, documentation and developer integrations. 6 tools Security and hash Generate passwords, calculate SHA hashes, inspect JWTs and prepare .env.example files without exposing production secrets. 5 tools QR codes Create 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.