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20 free tools

Free Developer Tools

JSON, YAML, Base64, hashes, JWT, regex, UUIDs, timestamps, diffs, colours, DNS, SSL and HTTP header checks. Free to use, no sign-up.

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Free Developer Tools: JSON, YAML, Base64, hashes, JWT, regex, UUIDs, timestamps, diffs, colours, DNS, SSL and HTTP header checks. Free to use, no sign-up. This page lists 20 free tools, including IP Subnet Calculator, Cron Expression Builder, Color Converter and CSS Gradient Generator. All of them are free, need no sign-up and run in your browser.

IP Subnet CalculatorNetwork, broadcast, host range, masks and subnet splits for IPv4 and IPv6.Runs in your browserCron Expression BuilderBuild or explain cron schedules and see the next 10 run times.Runs in your browserColor ConverterConvert HEX, RGB, HSL, HSV and CMYK and check WCAG contrast.Runs in your browserCSS Gradient GeneratorBuild linear, radial and conic gradients and copy the CSS.Runs in your browserHTTP Status CodesSearchable 1xx to 5xx status code list with SEO notes.Runs in your browserLorem Ipsum GeneratorPlaceholder paragraphs, sentences, words or lists in Latin or English.Runs in your browserDNS LookupCheck DNS records plus SPF, DMARC and DKIM email authentication.Checked on our serverSSL Certificate CheckerCheck SSL expiry, issuer, covered names and hostname match.Checked on our serverHTTP Headers CheckerStatus, response time, all headers and a security header score.Checked on our serverWhat Is My IPYour public IP address plus browser, screen and time zone details.Checked on our serverJSON YAML XML CSV ConverterConvert JSON, YAML, XML and CSV in any direction with line-level errors.Runs in your browserBase64 Encoder and DecoderEncode and decode Base64 text and files, with data URIs and image preview.Runs in your browserHash Generator (MD5, SHA-256, HMAC)MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes and HMAC for text or files.Runs in your browserJWT DecoderDecode JWT header and payload with readable expiry dates and status.Runs in your browserRegex TesterTest regex live with highlighted matches, groups, replace preview and explanations.Runs in your browserUUID GeneratorGenerate UUID v4 and v7 in bulk with formats, plus a UUID inspector.Runs in your browserUnix Timestamp ConverterConvert Unix timestamps to dates and back across time zones.Runs in your browserText Diff CheckerCompare two texts side by side or inline by line, word or character.Runs in your browserMarkdown EditorWrite Markdown with live preview, auto-save and HTML export.Runs in your browserText Case ConverterConvert text to upper, title, sentence, camel, snake and kebab case.Runs in your browser
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SEO ToolsAudit websites, research keywords, write meta tags, generate schema and check links, headings, canonicals and redirects.AI Writing ToolsDraft blog posts, product and business descriptions, emails and ad copy with proven copywriting formulas.Social Media ToolsCaptions, bios, hashtags, posts, YouTube titles, content calendars and engagement maths.Digital Advertising ToolsBudget, CPC, CPM, CTR, ROAS, ROI, conversion and cost-per-lead calculators for Google and Meta ads.Website Development ToolsSpeed and uptime checks, formatters, minifiers, JSON, URL and UTM tools, image compression and colour palettes.Local SEO ToolsLocal audits, Google Business descriptions and posts, review replies, local keywords, citations and NAP checks.Business & Marketing ToolsBudgets, strategies, personas, funnels, competitor analysis, business names, slogans, proposals and pricing.Creative ToolsLogo concepts, social and ad images, YouTube thumbnails, product photos, background removal and image enhancement.Everyday ToolsWeather, QR code maker and scanner, currency and unit converters, calculators, notes, expenses and WhatsApp tools.PDF & Image ToolsScan documents, merge, split and compress PDFs, convert images to PDF, and resize, crop, convert and watermark images.
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FAQ

Free Developer Tools: common questions

Are these developer tools really free?

Yes. All 20 developer tools on this page are 100% free to use, with no trial, no credit card and no limit on everyday use. A free account is optional and only saves your work so you can open it on your other devices.

Do I need to sign up or install anything?

No. Every tool works straight in your browser on a phone, tablet or computer. Most of them also work offline in the free Hayyat Networks Android app. Signing in with Google or email is optional and keeps your saved data synced.

Is my data private when I use these tools?

Tools that run in your browser process everything on your own device, and nothing you type is sent to us. Tools marked as checked on our server only read public information such as a website address. We never sell or share your data.

Which developer tools should I start with?

Most people start with Base64 Encoder and Decoder, Color Converter and Cron Expression Builder. Each tool page explains how it works, the formulas or checks it uses and its limitations, so you can pick the right one and trust the result.

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