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.
38 tools · 6 categories · 5 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 data for development workflows. UUID Generator · Password Generator · URL Encoder / Decoder · JSON Formatter 10 tools Finance Calculators and validators for invoices, salaries, loans and banking test data. Loan Calculator · French Notary Fees Calculator · VAT Calculator · Gross Net Salary Calculator 5 tools Utilities Practical tools for production, QA, test data and everyday tasks. Word Counter · Timezone Converter · Color Converter · Fake French Address Generator 4 tools Text Transform, compare, count or convert text content. Base64 Encoder / Decoder · Markdown to HTML · Lorem Ipsum Generator · Diff Checker 3 tools Images Prepare, convert and share images directly from your browser. QR Code Generator · HEIC to JPG · Image Compressor 2 tools PDF Create, merge or convert PDF files in the browser. Merge PDF · Image to PDF
Catalog
Search all tools
Filter by name, need, format, category, keyword or business entity.
38 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 Decode and inspect JSON Web Tokens, headers, payloads and claims. Open tool Cron Expression Parser Parse a cron expression and preview upcoming run times. Open tool MD5 Hash Generator Calculate the MD5 hash of text for checksums, compatibility and legacy comparisons. 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 Diff Checker Compare two texts, JSON snippets or code blocks and highlight differences. Open tool QR Code Generator Create a QR code PNG for a URL, text, contact detail or shareable information. 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 monthly payments, total cost and interest for a loan. 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 Fake French RIB Generator Generate fake French RIB examples with IBAN and BIC for forms, QA and mockups. 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 Number Validator Check the local format of a French intra-community VAT number. Open tool Fake French Address Generator Generate fictitious French addresses for forms, CRM tests, checkout mockups and QA datasets. Open tool Fake Identity Generator Generate fictitious user profiles for form tests, prototypes, QA and mockups. 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.
7 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. 6 tools Business invoicing Group the tools needed to prepare invoice tests, check French company identifiers, calculate VAT and validate French VAT number structure. 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.
Comparison
Which workflow should you use?
| Need | Recommended page | Related tools |
|---|---|---|
| Generate test data | Test data | UUID, fake identity, fake address, SIRET, RIB |
| Test a banking form | Banking test data | RIB, IBAN/BIC, 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, RIB, amounts |
| Check secrets, tokens and hashes | Security and hash | Password, SHA256, MD5, JWT, .env example |
Organization
A catalog that is easy to scan and crawl
Each tool has a clean URL, explicit title, short definition, use cases, FAQs and internal links. This format helps people and search systems understand the tool quickly.
- Tool pages answer simple actions: generate, validate, convert and calculate.
- Workflow pages answer complete needs: test data, fake RIB, invoicing and data conversion.
- The catalog acts as the pillar page that links every tool and category.
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.
Why are tools organized by categories and workflows?
Categories make browsing easier, while workflows connect tools used together for banking test data, invoicing, security or data conversion.
Which tools help prepare test data?
Combine UUID, fake identity, fake address, fake SIRET/SIREN, fake RIB, 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.