Immediate access
Open a tool, paste content or select files, then copy the result.
38 free online tools
Free tools for developers, makers and QA workflows.
Convert, compress, validate, generate and calculate from one fast catalog. OnSubmit groups practical browser-based tools for PDFs, images, text, developer data, test data and everyday calculations.
6 categories Local processing Fast to use
Tools
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Search by name, workflow, format or keyword.
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
Workflows
Find the right group of tools
Useful workflows that connect several tools around the same task.
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.
Why OnSubmit
Simple tools that open fast and stay useful
Browser-first
Compatible tasks run directly on your device to keep short workflows short.
Easy to rediscover
Each tool has a dedicated page with explanations, FAQs and related tools.
FAQ
Frequently asked questions
Are files sent to a server?
Compatible tools process data directly in the browser. If a tool requires external processing, the page should make that clear before use.
Why does every tool have its own page?
A dedicated page makes the tool easy to open directly, share with a precise link and understand through focused explanations.
Do I need an account?
No. Public OnSubmit tools are free to use without signup.