Compile LESS to CSS Online — Browser LESS Compiler
Compile LESS to CSS with less.js locally. Compress output, optional source maps — runs entirely in your browser.
Developer notes
• External @import paths cannot resolve — paste complete LESS in the editor. • Inline JavaScript in LESS is off by default; enable only if you trust the source. • Strict math requires parentheses around calculations when enabled. • Auto-compile on paste/sample; typed edits need Compile (⌘↵). • Pair with beautify-less or minify-css downstream.
Options
When teams pick this route
• Convert legacy LESS components to CSS for migration. • Preview parametric mixins before integrating into a build. • Share compiled CSS with teammates who do not use LESS. • Quick-check guard expressions and operations.
Worked examples
Variables and operations
LESS input
Compiled CSS
Parametric mixin
LESS input
Compiled CSS
Navigate related tools
Beautify LESS with beautify LESS, decompress with unminify LESS, or browse the CSS preprocessors hub.
LESS compiler FAQ
Browser-only compilation
Why can't I use @import for Bootstrap or other libraries?
The compiler runs client-side without filesystem or network access to resolve external files. Include the LESS you need directly in the editor.
What does Strict math do?
When enabled, calculations like 8px + 4px require parentheses. This matches stricter LESS compiler modes used in some build pipelines.
When does compilation run automatically?
On paste and sample load. Typing alone does not trigger compilation — use Compile or ⌘↵.
CSS preprocessors
Compile SCSS or LESS to standard CSS in the browser — pair with beautify or minify for a full stylesheet workflow.
Explore other tool categories
Minify
Shrink code and assets for production — minify JavaScript, CSS, HTML, JSON and XML before gzip or CDN deploy.
Beautify
Make code readable with consistent indentation — beautify JavaScript, CSS, TypeScript, SCSS, LESS, Markdown, GraphQL, SQL, YAML and more in your browser.
Unminify
Expand minified or compressed code — unminify JavaScript, CSS, TypeScript, SCSS, LESS, SQL, YAML and other formats when debugging or reviewing.
Conversion
Transform data between JSON, YAML, XML and CSV locally — no server uploads.
JSON Tools
Validate, format, diff and explore JSON payloads — complementary to minifiers and converters.
SVG Tools
Preview, optimize with SVGO, export Data URI, resize, beautify, convert to JSX and validate SVG — all in your browser.
DevOps & Infra
Terraform HCL format/validate/minify, Dockerfile format & lint, Docker Compose and .env validation.
CI/CD
GitHub Actions and GitLab CI — format YAML and check workflow/job structure in your browser.
Logs & observability
Line-oriented JSON/NDJSON and Nginx/Apache access logs — format, filter, validate, and CSV/TSV.
Kubernetes
Multi-doc manifests, structural validate, Ingress/Deployment starters, and Helm values formatting.
Networking / IP
CIDR, subnets, and IPv4/IPv6 helpers — in your browser.
Security & tokens
JWKS, X.509 certificates, and secrets scan — browser-local.
API & schemas
OpenAPI tools to format, validate, and lint your specs.
Encoding
Encode or decode Base64, URL components and HTML entities — client-side only.
Developer utilities
Timestamps, UUID, ULID, Nanoid, cron, passwords, regex, slugify, number bases, case, text diff, and chmod — all client-side.
Text & Markdown
Count words, build Markdown TOCs, and clean line lists — all in your browser.
Serialization
Serialize and deserialize PHP data structures beside JSON workflows.