Developer

Inspect and format URLs, code, network data and structured text. Network tools identify when a request uses an external provider.

76 tools in this category.

• JSON formatter

  Validate and format or minify JSON. Syntax errors are reported without executing input.

• Base64

  Encode or decode UTF-8 text as Base64. Base64 is not encryption.

• URL encoding

  Encode or decode a URI component; invalid percent sequences are rejected.

• HTML entities

  Encode &, <, > and quotes, or decode common named and numeric entities. Results remain inert text.

• Inspect JWT

  Decode JWT header and payload locally. Signature, issuer, audience and expiry are NOT verified.

• UUID generator

  Generate one to 100 random version-4 UUIDs using the platform cryptographic random generator.

• Text hash

  Compute a SHA hash of UTF-8 text. Not an encryption or password-storage tool.

• String escaping

  Produce or parse a quoted JSON string literal.

• CSV ↔ JSON

  Convert CSV with a header row to JSON objects or JSON objects to CSV. Export neutralises spreadsheet formula prefixes.

• Number bases

  Exact integer conversion between bases 2 and 36, up to 256 source digits.

• Color contrast

  Compare relative sRGB luminance and check WCAG AA/AAA text contrast thresholds.

• URL inspector

  Inspect the components of a URL locally. The entered URL is never requested.

• Regex tester

  Test regular expressions in a disposable worker with a timeout and bounded output to prevent interface freezes.

• XML formatter

  Validate and format XML without loading external resources. DTD and entity declarations are rejected.

• YAML ↔ JSON

  Convert safe YAML data to JSON or JSON to YAML. Input is bounded; executable tags and anchors/aliases are disabled.

• File checksum

  Compute SHA-256, SHA-384 or SHA-512 for a local file without uploading it. Large files still require memory.

• Cron schedule

  Validate five-field cron and list next occurrences in UTC. Supports numeric lists, ranges, steps and standard day-of-month OR weekday semantics; no command execution.

• Placeholder text

  Generate original, neutral English placeholder paragraphs for layout testing. The text is not a quote from a book.

• IPv4 subnet calculator

  Local IPv4 arithmetic: network address, mask, broadcast and address range. Does not contact or scan any network.

• Browser information

  Shows this browser’s reported user agent, locale and screen capabilities locally. Values may be reduced or spoofed. Nothing is sent to an external service.

• My connection address

  Shows the address observed by this deployment. Forwarded public IP is trusted only on Cloudflare; localhost is labelled local.

• Safe request headers

  Displays an allow-listed subset of your request headers. Cookies, authorization and other secrets are never echoed.

• Public DNS records

  Read public DNS records through fixed DNS-over-HTTPS resolvers. No port scanning, private target fetches or arbitrary URL proxy.

• Duplicate code scan

  Finds repeated consecutive line blocks in code.

• Dependency cycles

  Finds cycles in a module dependency edge list.

• REUSE header check

  Checks pasted file snippets for SPDX markers.

• Conventional changelog

  Groups Conventional Commit messages into a changelog draft.

• OpenAPI client stub

  Generates a small JavaScript fetch client from an OpenAPI description.

• AsyncAPI handlers

  Generates event handler stubs from AsyncAPI channels.

• Proto compatibility

  Checks simple Proto field-number compatibility risks.

• RISC-V tiny trace

  Traces a tiny educational subset of RISC-V instructions.

• HTML element extract

  Extracts text for a selected HTML tag from supplied markup.

• Secret scanner

  Scan pasted repository text for common secret patterns and return masked findings only.

• SBOM from package JSON

  Create a small software component list from pasted package.json or package-lock.json content.

• Dependency license overview

  Summarize license fields found in pasted package metadata without contacting registries.

• Password guess estimate

  Estimate password guessability locally with transparent entropy heuristics; the password is not stored or sent.

• JSON Schema form

  Generate a small static HTML form from common JSON Schema object properties.

• Lite JSON Schema check

  Validate common JSON Schema object rules: type, required, properties, enum, min/max and string length.

• CBOR inspector

  Decode common CBOR values from hex or base64 and show a bounded structure tree.

• GraphQL SDL map

  Summarize GraphQL SDL types, fields and local type references without executing a server.

• SQL DDL builder

  Generate a simple CREATE TABLE statement from a table name and column lines.

• PostgreSQL EXPLAIN summary

  Read JSON EXPLAIN output and list plan nodes, costs, rows and timing.

• SemVer range check

  Check whether a semantic version satisfies common range expressions.

• Automata minimizer

  Validate and minimize a small deterministic finite automaton from JSON.

• ESLint check

  Find JavaScript problems with the real ESLint Linter engine.

• Stylelint check

  Find CSS rule violations with Stylelint.

• HTML validate

  Validate semantic HTML with html-validate recommended rules.

• TypeScript check

  Type-check a TypeScript fragment with the TypeScript compiler API.

• Babel transform

  Transform modern JavaScript for older browsers using Babel preset-env.

• Terser minifier

  Minify JavaScript and show original, minified and gzip-size estimates.

• cssnano minifier

  Minify CSS with cssnano on PostCSS and show size savings.

• Spectral API lint

  Lint OpenAPI or AsyncAPI descriptions with Spectral rulesets.

• TSDoc check

  Parse and validate TypeScript documentation comments with TSDoc.

• Notebook diff

  Structurally compares two .ipynb files: added, removed and changed cells, source and outputs.

• Sprite atlas

  Packs icon rectangles into a compact atlas: placements, utilisation, JSON and SVG.

• Profile flamegraph

  Builds a flamegraph from a CPU profile (Chrome/V8): self and total time per function, CSV and SVG.

• DXF inspector

  Reads ASCII DXF: counts entities, computes the drawing bounding box and extracts text labels.

• Protocol Buffers

  Encodes and decodes protobuf wire-format messages from a .proto schema. Shows bytes and parsed JSON.

• Git history simulator

  Runs a sequence of git commands (init, commit, branch, checkout, merge, rebase, log) and shows the commit and branch graph.

• Design tokens

  Flattens nested design tokens into CSS custom properties, SCSS, JSON or a JS module with flat names.

• ELF and PE inspector

  Parses executables: class, architecture, entry point, sections and symbols for ELF; header and sections for PE.

• .class inspector

  Reads a compiled Java class: version, constant pool, class name, superclass, fields, methods and attributes.

• Binary format schema

  Parses binary data with a declarative schema: integer types, fixed-length strings and bytes, repeats by expression.

• SQL inspector

  Parses SELECT statements: tables, columns and aliases, WHERE, GROUP BY, ORDER BY, LIMIT, and formats the query.

• PMTiles inspector

  Reads the PMTiles v3 archive header: tile type, compression, zoom range, bounds, centre and content statistics.

• GraphQL schema

  Parses a GraphQL schema and query, checking fields, arguments, required arguments, selection sets and variable declarations.

• Workflow graph

  Validates a LiteGraph-style node graph: node and port existence, type compatibility, optional inputs, cycles, orphan nodes and the execution order.

• Ohm grammar

  Parse a PEG-style grammar with Ohm and show the concrete syntax tree or the exact failure position.

• Earcut triangulation

  Triangulate a polygon with holes using earcut and verify that the triangle area matches the polygon area.

• Avro inspector

  Inspect Avro schemas and read or write real Avro object container files from raw bytes.

• Arrow IPC

  Decode or encode Apache Arrow IPC file bytes and show the real column schema.

• X.509 inspector

  Parse an X.509 certificate and list its fields. This is not trust, chain or revocation validation.

• WAT ↔ WASM

  Convert WebAssembly text to binary and back with WABT, and inspect imports and exports without executing code.

• MDN browser compatibility

  Look up real browser support data from the MDN browser-compat-data dataset.

• Tree-sitter syntax tree

  Build a real Tree-sitter syntax tree for supported languages and list named nodes and error nodes.

• Safe HTML preview

  Sanitize supplied HTML in the browser with DOMPurify and preview it in a sandboxed frame.