The Big LearnThe Big Learn
The Big Learn
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Free · in-browser · no sign-up

Free Online Developer Tools

The Big Learn brings together the utilities developers reach for every day — Base64 and URL encoding, JSON and YAML formatting, JWT and certificate inspection, hash, UUID and password generation, QR codes, OCR and PDF editing. Everything runs in your browser, with no sign-up and no cost.

28 tools 4 categories 0 sign-ups required
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Text Tools

Neon text editing workspace with structured lines and transformation controlsText EditorClean, split, replace and transform text. Open tool Neon document template with connected variable placeholders and generated text blocksText TemplateFill in text using reusable variables. Open tool Elegant neon QR matrix with finder patterns, data modules and scanning beamsText to QR CodeGenerate QR codes from text and URLs. Open tool Multiple screens synchronizing glowing text through real-time network channelsText SharerShare temporary text between screens in real time. Open tool Luminous document image being scanned into precise editable text charactersOCR ConverterExtract text from images using OCR. Open tool Two glowing text documents connected by highlighted additions and removalsText DiffCompare two blocks of text and highlight the differences. Open tool

Developer Tools

Glowing binary data transforming into structured Base64 character blocksBase64 Text ConverterEncode and decode text in Base64. Open tool Neon web address branching into identifier, locator and name componentsURL CodecEncode and decode URLs quickly. Open tool Glowing JSON document with nested objects, arrays and formatting guidesJSON EditorFormat, minify and stringify JSON. Open tool Data blocks flowing through a cryptographic hash engine into fixed-length fingerprintsHash GeneratorGenerate MD5, SHA-1, SHA-256 and SHA-512 hashes. Open tool Split view of a glowing OpenAPI document in YAML next to rendered API endpoints with colored HTTP method badgesSwagger Viewer & EditorView, edit and test Swagger/OpenAPI specs: convert versions, call endpoints and export standalone HTML docs. Open tool Side-by-side JSON and YAML trees connected by highlighted matching and different fieldsJSON & YAML ComparatorCompare fields of two JSON or YAML files: missing on each side and differing values. Open tool Glowing UUID segments arranged across a distributed network of database nodesUUID GeneratorGenerate v4, v7 and v1 UUIDs with formatting options. Open tool Digital clock and timeline flowing from the Unix epoch into modern systemsUnix TimestampConvert dates and times to Unix timestamps. Open tool Futuristic IPv4 address divided into four binary octets and branching into organized CIDR subnet rangesIPv4 CIDR CalculatorCalculate subnet ranges, masks, network, broadcast and usable addresses. Open tool Three glowing JWT token segments connected to a cryptographic signature shieldJWT ManipulatorInspect header, payload and signature of JWT tokens. Open tool Five encrypted token segments entering a luminous security vaultJWE ManipulatorSplit header, encrypted key, IV, ciphertext and tag of JWE tokens. Open tool Secret key and message entering a dual-layer hash authentication mechanismHMAC GeneratorCompute HMAC with SHA-256, SHA-512 and other algorithms. Open tool Digital X.509 certificate under a magnifying glass with trust-chain connectionsX.509 Certificate ViewerRead information from X.509 digital certificates. Open tool Cryptographic key forge creating a luminous X.509 certificate and RSA key pairX.509 Key & Certificate GeneratorGenerate X.509 digital certificates with RSA keys. Open tool Certificate and private key aligned in a glowing cryptographic validation matrixCertificate & Key ValidatorValidate certificate expiry and match certificates, public and private keys. Supports PEM, CRT, CER, DER, PFX and P12. Open tool Neon Kanban board with organized task columns, progress indicators and completed cardsKanbanAppKanban board to organize tasks and projects. Open external tool

Generators

Secure password characters emerging from a cryptographic random generator and lockPassword GeneratorGenerate secure passwords with length and character options. Open tool Abstract Brazilian test document numbers with verification digits and validation marksCPF & CNPJ GeneratorGenerate valid CPF and CNPJ numbers for software testing. Open tool

Image, Graphics & PDF Tools

Neon flowchart with connected process nodes, decisions and directional pathsFlowchart EditorDraw flowcharts with shapes, arrows and colors; import and export as Mermaid and XML. Open external tool Multiple PDF pages and images converging into one polished digital documentPDF & Image MergerMerge multiple PDFs and images into a single PDF or image file, with reordering. Open tool One PDF document separating into clean individual pages and image previewsPDF SplitterSplit a PDF into individual pages, download as a ZIP of PDFs or JPGs. Open tool Ordered photographs transforming into a professionally bound digital PDF documentPDF CreatorArrange images and create a single PDF in your browser. Open tool Luminous document image being scanned into precise editable text charactersOCR ConverterExtract text from images using local OCR with Tesseract.js. Open tool

Latest articles

Guides explaining the standards and concepts behind each tool.

Neon web address branching into identifier, locator and name componentsWeb StandardsURI vs URL: The Difference Explained with ExamplesUnderstand the difference between URI, URL and URN: RFC 3986 definitions, generic syntax, schemes, relative references and real code examples.19 min readSplit view of a glowing OpenAPI document in YAML next to rendered API endpoints with colored HTTP method badgesAPIsSwagger and OpenAPI: History, Versions and Technical DifferencesThe history of Swagger and OpenAPI, who standardizes the specification, and the technical differences between Swagger 2.0, OpenAPI 3.0 and 3.1.22 min readNeon text editing workspace with structured lines and transformation controlsText ProcessingOnline Text Editors: How Text Transformation WorksLearn how online text editors normalize, split, replace, count and transform text, with technical examples and practical use cases.15 min readNeon document template with connected variable placeholders and generated text blocksText ProcessingText Templates and Variables: A Practical Automation GuideUnderstand how text templates replace variables to generate consistent messages, commands and documents, including grammar, rendering rules and examples.14 min readTwo glowing text documents connected by highlighted additions and removalsText ProcessingText Diff Explained: Algorithms, Changes and Real UsesLearn how text diff tools detect additions, removals and unchanged sequences using LCS-style algorithms, with technical examples.16 min readGlowing binary data transforming into structured Base64 character blocksData EncodingBase64 Encoding and Decoding: How It Really WorksUnderstand Base64 encoding, its 24-bit conversion process, padding, UTF-8 handling and practical uses in APIs, email and data URLs.15 min readNeon web address flowing through percent-encoded character symbolsWeb StandardsURL Encoding Explained: Percent-Encoding in PracticeLearn how URL percent-encoding represents reserved characters and UTF-8 bytes in paths and query strings, including standards, normalization and security.16 min readGlowing JSON document with nested objects, arrays and formatting guidesData FormatsJSON Formatting, Minification and Validation ExplainedA technical guide to JSON syntax, parsing, formatting, minification and stringification for APIs, configuration and web applications.17 min readSide-by-side JSON and YAML trees connected by highlighted matching and different fieldsData FormatsHow to Compare JSON and YAML StructurallyLearn how structural comparison parses JSON and YAML, walks object paths and reports missing fields and different values.18 min readGlowing UUID segments arranged across a distributed network of database nodesIdentifiersUUID v1, v4 and v7: Generation, Structure and UsesCompare UUID v1, v4 and v7, understand their bit layout, randomness, ordering and practical use in distributed systems.18 min readDigital clock and timeline flowing from the Unix epoch into modern systemsDate and TimeUnix Timestamps: Epoch Time, Precision and Time ZonesUnderstand Unix timestamps in seconds and milliseconds, UTC conversion, time zones, precision and practical application behavior.16 min readAbstract Brazilian test document numbers with verification digits and validation marksTesting DataCPF and CNPJ Check Digits for Software TestingLearn how CPF and CNPJ check digits are calculated, why valid test documents matter and how to use generated values responsibly.18 min read
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Frequently asked questions

What utily.tools is, how it handles your data and what it costs.

What is utily.tools?

utily.tools is a free collection of online developer tools that run in your browser. It brings together text utilities, encoders and decoders, JSON and YAML tooling, certificate and token inspectors, hash and password generators, PDF utilities and QR code generation in a single place, so you do not need to install anything or jump between sites.

Are the tools really free to use?

Yes. Every tool on utily.tools is free, with no account, no sign-up and no usage limits. There is no paid tier and no trial period.

Do I need to create an account or install anything?

No. You open the tool you need and start using it immediately. utily.tools runs entirely in a modern web browser, on desktop or mobile, with no extension, download or registration required.

Is my data safe? Does anything get uploaded to a server?

The vast majority of the tools process your input locally in the browser, which means the text, files, certificates and tokens you paste never leave your device. The exceptions are the features that need a server by definition, such as the shared text tool that synchronises content between screens. Even so, avoid pasting production secrets or private keys into any online utility, here or elsewhere.

Which tools does utily.tools offer?

The catalogue is grouped into text tools, developer tools, generators and image, graphics and PDF tools. It includes a Base64 converter, URL encoder and decoder, JSON editor, JSON and YAML comparator, JWT and JWE inspectors, X.509 certificate viewer, generator and validator, hash and HMAC generators, UUID and password generators, Unix timestamp converter, IPv4 CIDR calculator, Swagger and OpenAPI editor, text diff, OCR converter, QR code generator and PDF merger, splitter and creator.

Can I use utily.tools offline?

Tools that run fully in the browser keep working while the page stays open, even if the connection drops. However, the site is not installable as an offline application, so the first load and any navigation to another tool require an internet connection.

What is the difference between the Tools and the Learn sections?

The tools solve an immediate task, such as decoding a token or calculating a subnet. The Learn section holds long-form study material on corporate API fundamentals and architecture, published in English, Portuguese and Spanish, while the Articles section explains the standards and concepts behind each individual tool.

Can I use utily.tools for commercial or professional work?

Yes. The tools are intended for everyday professional use by developers, QA engineers, security analysts and infrastructure teams. Bear in mind the usual precaution about sensitive material: use test data when you are inspecting formats and structures.

How can I report a bug or suggest a new tool?

The About page lists the contact details for feedback. Suggestions for new tools, bug reports and corrections to the articles are all welcome, and the catalogue grows regularly based on them.

Pick a tool and get to work

Every utility runs in your browser, ready to use. Prefer to build a deeper foundation first? The Learn section covers networking and API fundamentals step by step.

Explore the Learn section