Online toolbox: 67 everyday developer and office tools

Local Toolbox: 67 sign-up-free online tools covering JSON formatting, timestamp conversion, QR codes, image compression and résumé editing. Most tools run entirely in your browser and never upload your input; AI features are pay-per-use.

An online toolbox that runs mostly in your browser, with no sign-up required, Apart from AI watermark removal and AI background removal (the image is sent after payment), AI image generation (the prompt and settings are sent after payment), AI upscaling (an image is uploaded and then processed), AI annotation (images are uploaded for the model after payment), AI flowchart and mind-map generation (your text is sent after payment) and the accounting helper (your figures are sent after payment), every tool computes locally in your browser and your input never leaves the device. The IP page asks our own backend for your outbound address but sends none of your input.

Categories

JSON & XML (5 tools)

• JSON formatter
  Type on the left, formatted output on the right; unquoted keys are repaired automatically, with ascending / descending order, one-click minify, copy and download.
• XML formatter
  Type on the left, formatted output on the right; tags, attributes, entities and text are preserved exactly, with ascending / descending order, one-click minify, copy and download.
• JSON diff
  Paste one JSON document on each side: both are formatted and compared field by field, with keys sorted identically by default (switchable), missing / extra / changed fields highlighted in different colours, counts for added / removed / modified fields and a copyable diff list.
• JSON to XML
  JSON on the left, XML generated live on the right: fields become tags, @-prefixed fields become attributes and arrays become repeated tags. The same lenient parser as the JSON formatter page applies (unquoted keys, single quotes, comments and trailing commas are repaired), with sorting, minify, copy and download.
• XML to JSON
  XML on the left, JSON generated live on the right: attributes become @-prefixed fields, repeated tags become arrays and text-only elements become strings, with sorting, minify, copy and download.

Dates (5 tools)

• Timestamp converter
  Recognises second- and millisecond-precision timestamps and compact dates, converts both ways, and shows local time, UTC, ISO 8601 and relative time live.
• Date formatter
  Formats a date-time with your own template or a common preset, switchable between local time and UTC, with per-row copy.
• Date difference
  Enter a start and an end time to get the difference in days, hours, minutes and seconds, plus calendar days, working days and total duration.
• Date calculator
  Add or subtract years, months, weeks, days, hours, minutes and seconds from a base time to get the target date, time and timestamp.
• Time zone converter
  Pick a base time and its time zone to see the local time in common zones around the world side by side — daylight saving is applied automatically — with per-row and whole-table copy. The world map below lets you tap anywhere to see that zone's time, with zoom and pan.

Resume (2 tools)

• Resume editor
  Fill in résumé content through a form, pick from 100 role templates and 104 layouts, then copy HTML / Markdown or export PDF.
• AI résumé
  Paste or edit your Markdown résumé on the left, fill in your years of experience, industry and target role, and let the AI rewrite it into a sharper, better-targeted version: employers, schools, dates and numbers are kept as they are, while emphasis and wording are adjusted for the role. Preview it on the right and export a PDF. Charged per run (¥0.5) via Alipay, and your résumé is sent to our backend only after payment succeeds.

Codes & ID cards (7 tools)

• QR code generator
  Turn text or a URL into a QR code live, with adjustable error correction, size, margin and colours, downloadable as PNG or SVG.
• QR code decoder
  Upload, drag or paste an image to decode the QR code inside it, with the code version and content stats, copyable in one click.
• Barcode generator
  Turn digits or letters into a barcode live — Code 128, Code 39, EAN-13, EAN-8, UPC-A, ITF-14 and Codabar — with adjustable bar width, height, margin, human-readable text and colours. EAN / UPC / ITF check digits are filled in automatically, and the result downloads as PNG or SVG.
• ID card parser
  Enter a Chinese ID number to parse the issuing region, date of birth, gender, age, Chinese zodiac and star sign plus the checksum result; legacy 15-digit numbers are upgraded automatically.
• ID card validator
  Paste a batch of Chinese ID numbers to validate length, date of birth and checksum one by one, with per-row pass / fail reasons and one-click copy of the valid ones.
• Region lookup
  Search by 6-digit region code, full ID number or region name to get the province / city / district path; the built-in dataset resolves down to county level.
• ID card generator
  Generate Chinese ID numbers with valid checksums from province / city / district, date of birth, gender and count. Regions go down to county-level cities, numbers are unique within a batch, and the output is for testing and development only.

Images (11 tools)

• Image compressor
  Upload an image and re-encode it to the target format, quality and maximum edge length; before / after size and dimensions are compared live and nothing is downloaded until you confirm.
• Image cropper
  Upload an image and drag out the crop area — rectangle, rounded rectangle or circle (ellipse) — optionally locking common ratios such as 1:1, 4:3 and 16:9. The crop is previewed live and can be exported as PNG / JPEG / WebP with transparency.
• Collage maker
  Set your own canvas size with a transparent, solid or image background; add text (font size, colour and typeface — 20+ free-for-commercial-use Chinese fonts including 7 brush-script faces, or your own uploaded font), your own images and built-in stickers, then drag, scale, flip and rotate them before exporting PNG / JPEG / WebP.
• Image to Base64
  Convert an image to a Data URL or plain Base64 text, or turn Base64 back into an image — with copy and download.
• Code to image
  Paste code, pick a language (JavaScript, Java, Python, Go, Rust, Vue and 15 more) and a theme (20 light / dark themes), set font size, padding, window style (macOS / Windows / Linux) and line numbers, preview live and export PNG or JPEG.
• Favicon generator
  Upload a logo to get a full set of 16–512 px PNG icons plus a favicon.ico with 16 / 32 / 48 px inside. Background colour and margin are adjustable, everything downloads as a bundle, with the HTML tags ready to copy.
• AI watermark remover
  Upload an image and select the watermark by hand, pay per run; processing starts automatically once the Alipay payment succeeds, only the selected area is repainted, and the result can be downloaded right away.
• AI image generator
  Write a prompt, pick an aspect ratio (1:1, 4:3, 16:9, 9:16 and four more) and a resolution (2K ¥2, 4K ¥3); once the Alipay payment succeeds, AI renders a new image you can download straight away. Failed runs are refunded automatically.
• AI background remover
  Upload an image and let AI cut out the subject and remove the background, pay per run (¥1 each time); optionally add a one-line background description (e.g. “a white studio backdrop”) to help it tell the subject apart, output with a transparent background (PNG) or in the original format / JPEG, with the result matching the original size. Failed runs are refunded automatically.
• AI upscaler
  Upload an image, choose a resolution (2K ¥2, 4K ¥3) and a scene (portrait, landscape, architecture and 53 more, or leave it on the default prompt); after payment succeeds AI repaints it sharper at the original aspect ratio and you can download the result. Failed runs are refunded automatically.
• Image to ASCII art
  Turn an image into ASCII art: black & white maps brightness to character density while colour keeps per-character pixel colours. Charset (10 / 70 levels), columns, character size, brightness, contrast and invert are adjustable, with text copy and TXT / PNG / SVG / HTML export. Everything runs locally in the browser; the image never leaves your device.

Encryption (9 tools)

• SM2 / SM3 / SM4
  Everything SM in one page: SM2 key pairs and sign/verify, SM4 encryption (CBC / ECB) and SM3 digests, with ciphertext you can cross-verify.
• MD5
  Compute the MD5 digest of a text or a file in real time (32- or 16-character form, upper/lower case). Supports UTF-8 Chinese; files can be picked or dropped and are hashed in chunks with a progress bar. Digest only — the original text cannot be recovered.
• DES / 3DES
  DES and 3DES encryption with CBC / ECB / CTR modes, 5 padding options, keys and IV as text or hex (the IV can be generated randomly), ciphertext as hex or Base64.
• Hash calculator
  One input, eleven digests: MD5, the SHA-1/2/3 families and RIPEMD-160. HMAC mode (with key) is supported; every row copies in one click.
• AES
  AES-128/192/256 encryption with CBC / ECB / CTR / CFB / OFB modes, 5 padding options, keys and IV as text or hex (with random generators), ciphertext as hex or Base64.
• RSA key generator
  Generate RSA key pairs locally via Web Crypto: 2048 / 3072 / 4096 bits, exported as PEM text (SPKI public key, PKCS#8 private key) with one-click copy. Keys never touch disk and are gone once the page closes.
• RSA encrypt / decrypt
  Encrypt with a PEM public key and decrypt with the private key, or sign / verify directly. OAEP and PKCS1 schemes; long inputs are rejected with a clear hint.
• JWT encoder / decoder
  Decode a JWT into header and payload with field-by-field explanation, algorithm detection and expiry status — or build one the other way: wrap a payload JSON and sign it with HS256 / HS384 / HS512 (or none for debugging). Decoding does not verify the signature — the page says so explicitly.
• Password strength
  Breaks a password down: length, character mix, entropy and brute-force scale; detects keyboard runs, repeats, years and known weak passwords, with a 0-100 score and advice. Entirely on-device.

Diagramming (8 tools)

• Flowchart
  Drag any of the 15 flowchart shapes onto the canvas, tweak connectors and decision labels freely, import / export JSON, and export PNG / SVG / PDF.
• AI flowchart
  Describe how something happens in plain words (for example: “after a customer orders, the system checks stock — if there is enough it deducts stock and creates a shipping order, otherwise it shows out of stock and cancels the order”), and after payment the AI turns the steps, decisions and flow into a flowchart: laid out automatically, decisions drawn as diamonds, start and end coloured separately. Once generated you can drag nodes and double-click to retype them, or hit “Export data” and import it on the Flowchart page to swap shapes, colours and link types; PNG / SVG / PDF export works here too. Pay per use, ¥0.5 each; the description is sent to our backend to call the model only after payment succeeds, and failed calls are refunded automatically.
• Mind map
  Drag the central topic, branch topics and subtopics from the left panel onto the canvas — drop a node onto another to make it that node’s child — and the tree is laid out automatically on both sides (or all to the right). Double-click, or press Tab / Enter, to edit text and add nodes, and drag between two nodes to draw a relation line. Import and export Baidu Naotu .km data, and export PNG / SVG / PDF.
• AI mind map
  Paste in bullet points, notes or meeting minutes and, after payment, the AI turns them into a mind map: a central topic, first-level branches and nested subtopics, laid out on both sides with their own colours. Afterwards you can retype nodes and drag a node under a different parent, or hit “Export data” and import it on the Mind map page to keep adjusting — PNG / SVG / PDF and Baidu Naotu .km export are available as well. Pay per use, ¥0.5 each; the text is sent to our backend to call the model only after payment succeeds, and failed calls are refunded automatically.
• UML diagram
  Drag classes, interfaces, abstract classes, enumerations and packages onto the canvas, type attributes and methods straight into each node (one per line), and connect them with inheritance, realization, composition, aggregation, association or dependency — arrow heads and diamonds are drawn automatically. Import and export JSON data, and export PNG / SVG / PDF.
• Sequence diagram
  Sketch sequence diagrams by clicking or dragging from the palette: objects / stick actors, solid / dashed / open-arrow messages, self messages, notes, activation bars and stage dividers. Click any element on the canvas to rename it, restyle the line, swap the sender or receiver, move it up or down, with undo and redo. Prefer text? Switch to the script tab, type a few lines like “who -> whom: what” and apply them to the canvas in one go. JSON data can be imported and exported, the script is one click to copy, and the picture can be exported as PNG / SVG / PDF or copied to the clipboard. Four colour themes are available; the canvas follows the system’s light or dark mode while exported images always come on a light sheet. Rendering and export all happen locally in your browser — nothing leaves your machine.
• Mermaid diagram
  Paste Mermaid code in and it renders into a diagram locally in real time; syntax mistakes are reported with a line number and the reason while the last good diagram stays on the canvas. Both graph and flowchart syntax are supported, including every arrow type and subgraphs, with editable presets to start from. The theme follows your system’s light or dark mode, and PNG / SVG / PDF export is built in. Rendering and export happen entirely in your browser — the code never leaves your machine.
• AI Mermaid diagram
  Pick a chart type (14 in all: flowchart, sequence, class, state, ER, gantt, pie, quadrant, timeline, kanban, mind map, git graph, user journey and C4), type a description, and after payment the AI writes Mermaid code for that chart type directly. The result renders on the page immediately, and every chart type ships with a sample and prompt hints — one click fills the sample if you are stuck. Copy the code in one click, or hit “Edit on the Mermaid diagram page” to jump over with the code pre-loaded, then tweak the diagram by hand and export PNG / SVG / PDF. Pay per use, ¥0.5 each; the description is sent to our backend to call the model only after payment succeeds, and failed calls are refunded automatically.

Annotation & accounting (4 tools)

• Manual annotation
  Upload an image and mark the content by hand: drag out a horizontal box, or draw one and then rotate it to any angle; the four corner coordinates and all four edge lengths are shown live and can be copied as text or JSON, and the box can be drawn onto the image for export (the file is always named "date-time-coordinates-lengths.ext").
• AI annotation
  Upload 1 to 20 images, describe the target in one sentence (e.g. "mark the red chillies") and choose whether boxes should be axis-aligned or at any angle; the AI inspects each image and returns the four corner coordinates and four edge lengths of the clearest target it finds — one box per image — ready to copy as text or JSON. Exporting can draw the box if you want it, and without that option it is the original image. Charged per image (¥0.5 each) via Alipay, detection starts after payment. Charging is per image and so are refunds: when only some images fail, the fee for the failed ones is refunded automatically while the results for the rest are delivered as usual; when the whole batch fails the entire order is refunded, and if the model call succeeded but produced no usable boxes, the fee is not refunded.
• Financial statements
  Describe this month in plain words: money in and out, expenses you paid on the company’s behalf, social insurance and housing fund (paid from the company account or your own pocket), one row of salary and special deductions per employee, bank balances and money owed. Submitting produces a balance sheet and an income statement, every line explains how it was computed on hover, and the whole thing exports to PDF. A sample report is shown as soon as the page opens.
• Income tax calculator
  Enter monthly salary, social insurance and special deductions to get annual income tax and monthly take-home under cumulative withholding, and compare the two year-end bonus tax options.

More tools (16 tools)

• SQL formatter
  Paste SQL to get clause-aware line breaks, indentation and upper-cased keywords in real time, with one-click minify, copy and download as a .sql file.
• Nginx formatter
  Paste nginx.conf to re-indent it by brace level; directives, comments and quoted strings are preserved exactly and unbalanced braces are reported.
• URL encoder / decoder
  Switch between encoding and decoding with either encodeURIComponent or encodeURI scope, showing the encoded character count live.
• Regex tester
  Enter a regular expression and test text to highlight every match live, list each match position and its capture groups, and preview the replacement result.
• Markdown editor
  Edit Markdown on the left and preview it live on the right, with a toolbar that inserts headings, lists, tables and code blocks in one click; images and files can be uploaded, dropped or pasted in as embedded content, Markdown / Word / PPT / PDF / Excel / EPUB / RTF / OpenDocument documents convert to Markdown locally in your browser, and the rendered HTML is ready to copy or export as PDF.
• Password generator
  Generate strong random passwords from a length and character set, optionally excluding look-alike characters, in batches, with a strength and entropy estimate.
• Amount in words
  Convert an amount into Chinese financial capital characters (yuan, jiao, fen) along with the upper-case digits, the Chinese reading and a thousands-separated form.
• IP address
  Parse an IPv4 / IPv6 address into its type, binary and decimal forms and subnet details (network address, broadcast address, usable range). Opening the page also looks up your public outbound IP from our backend, configured per environment.
• Web-safe colours
  Browse all 216 web-safe colours grouped by the red channel (each channel steps 00 / 33 / 66 / 99 / CC / FF); click a swatch to select it, then copy the HEX, the 3-digit shorthand, RGB, HSL, HSV, CMYK and the contrast against black or white text. Any colour you type is snapped to the nearest safe colour, and you can filter by value or show greys only.
• Cron expression parser
  Paste a cron expression to see it in plain words with upcoming run times, or build it field by field; crontab and Quartz both work.
• Emoji library
  Browse all 1849 emoji from Unicode 15.1 in nine groups (smileys, people, animals, food and more). Search by Chinese or English name — everyday words like "red packet" or "happy birthday" work too — then click any emoji to copy it instantly; recent picks are remembered for next time. Everything runs locally in the browser; nothing is uploaded.
• Properties to YAML
  Paste Java .properties content and get a nested YAML that follows the dot hierarchy: equals, colon and whitespace separators are all supported, along with \t \n \uXXXX escapes and line continuations that end with a backslash. Every value is emitted as a string (single-quoted; multi-line content keeps its line breaks as a block scalar), comments and blank lines follow the entry they belong to, and keys that collide with nested children are flattened back to their full dotted names with a note at the end. Everything runs locally in the browser; nothing is uploaded.
• YAML to Properties
  Paste YAML content and get flattened .properties key-value pairs: nesting and arrays expand along the dot hierarchy (arrays use index keys), every value is emitted as a string and escaped the java.util.Properties way; whole-line and end-of-line comments move above the entry they belong to (in .properties a # only works at the start of a line — one appended after a value would be read into it), and the result can be re-sorted in ascending / descending order. Everything runs locally in the browser; nothing is uploaded.
• YAML validator
  Paste YAML and check the syntax as you type: when it is invalid, the page points at the exact line and column, shows the offending line with a ^ marker and gives a concrete fix suggestion (unclosed quotes, unbalanced brackets, misaligned indentation, duplicate keys, tab indentation, full-width colons and more); when it is valid, it reports the document, line and character counts plus warnings about legal-but-risky writing. Everything runs locally in the browser; nothing is uploaded.
• Electronic seal maker
  Draw an electronic seal locally and export it as a transparent PNG. Company seals take a name and code, a seal type (official / contract / finance / invoice, or custom), a circle or ellipse shape, an optional centre star and any text colour; the name and type text scale automatically with the character count. Personal seals come as a square four-character grid or a circle, in relief or intaglio carving and Song / Kai / Hei fonts. Everything is drawn in the browser; nothing is uploaded.
• Sign a PDF
  Stamp a seal onto a PDF: upload the document (up to 20 MB), drag the seal image to the spot you want on any page, or tick the edge seal to stamp along the right edge of every page. An encryption certificate (PKCS12) can be uploaded or generated online to add a digital signature that Adobe Reader verifies. Sealing happens in one pass inside server memory — the file, seal and certificate are never written to disk and are destroyed right after signing. Draw a transparent seal PNG with the electronic seal maker first for the best result.

FAQ

Is Local Toolbox free?

Almost every tool is free, needs no registration or sign-in, has no usage limit and the pages carry no pop-up ads; only a handful of features are charged per use: AI watermark removal at ¥1 per run, AI image generation at 2K ¥2 and 4K ¥3, AI upscaling at 2K ¥2 and 4K ¥3, AI annotation at ¥0.5 per image, AI résumé rewriting at ¥0.5 per run, AI flowchart at ¥0.5 per run, AI mind map at ¥0.5 per run and AI Mermaid charts at ¥0.5 per run, and the accounting helper with its spoken analysis ¥0.5 and report generation ¥1. Prices are stated on the corresponding page and follow the current price in the database, so pages update automatically.

How do I pay for the pay-per-use features?

Only Alipay online payment is supported for now. Clicking "Start" opens the payment window; once you have paid on the Alipay checkout page, processing starts automatically with no second click, one payment covers one run, a failed run is refunded automatically to the original payment method, and you can retry directly without being charged again. Nothing is uploaded before payment. AI output is stochastic, so there is a confirmation above the payment button that has to be ticked first, and the actual result is what counts.

Does the site store my content on a server?

No. Parsing, conversion and image processing mostly run locally in the browser, and closing the page releases the content; the IP address page only asks our backend for your outbound address and carries none of your input; every pay-per-use feature submits content to the backend only after payment succeeds (the image for watermark removal, the description and settings for image generation, the source image for AI upscaling, the images for AI annotation, the résumé text for AI résumé, the text description for AI flowcharts and mind maps, the entered figures for financial statements) and returns the result as soon as processing finishes; nothing is written to server disk and none of it is retained.

Does every tool have its own link?

Yes. Each feature page has its own address, for example JSON formatting is at /json-format/, so reloading keeps you on the same tool and bookmarks or shared links go straight there.

Can I use it on a phone?

Yes. The layout is responsive and the tool panels stack one above the other on phones, with the same features as on desktop.

About Local Toolbox

Local Toolbox gathers the small tools you reach for every day into one place: formatters, encoding converters, date maths, ID card and address parsing, image and QR code handling, password and amount conversion. Open a page and start working — no sign-up, and almost every tool has no usage limit.

Most features compute inside your browser, so your input never leaves your device; the pages are plain static assets, load fast and keep working offline. The IP page asks our backend for your outbound address when it opens and sends none of your input. AI watermark removal, AI background removal, AI image generation and AI upscaling send content to our backend for inference (watermark removal is ¥1 per run; background removal is ¥1 per run; image generation and upscaling are priced by resolution — 2K ¥2, 4K ¥3); AI annotation sends images to a large model that locates the target and returns coordinates (¥0.5 per image, refunded only when every image in the batch fails); AI flowchart, AI mind-map and AI Mermaid chart generation send your text description to a model that builds the diagram (three separate products, charged ¥0.5, ¥0.5 and ¥0.5 per run respectively); and the accounting helper sends the income, expense, social-insurance and balance figures you fill in to generate a report (¥0.5 for the spoken analysis, ¥1 for the report). These features accept Alipay only, upload nothing before payment succeeds, and refund automatically if processing fails.

• Local first: Parsing, conversion, encoding and image processing all happen in your browser and nothing you type is uploaded (AI watermark removal and AI background removal need the image, AI image generation and upscaling need one upload to obtain a URL, AI annotation needs the images for the model, AI résumé rewriting needs your résumé text, AI flowchart and mind-map generation need your text description, and the accounting helper needs the figures you submit).
• Pay per use, prices in plain sight: Almost every tool is free, needs no account and has no usage limit. Only AI watermark removal (¥1 per run), AI background removal (¥1 per run), AI image generation and AI upscaling (2K ¥2, 4K ¥3), AI annotation (¥0.5 per image), AI résumé rewriting (¥0.5 per run), AI flowchart, mind-map and Mermaid chart generation (¥0.5, ¥0.5 and ¥0.5 per run) and the accounting helper (¥0.5 for the spoken analysis, ¥1 for the report) are charged per use. Payment is Alipay only, nothing is uploaded before you pay, and failed runs are refunded automatically.
• One link per tool: Every tool has its own link, so bookmarks and shared URLs always land on the same page.

Links

• Vue.js: The front-end framework behind this site
• Vite: Build tool
• MDN Web Docs: Web platform documentation
• Can I use: Browser compatibility tables
• Regex101: Regex debugging
• Schema.org: Structured data vocabulary