dompurify vs xss

utility

dompurify

xss

DOMPurify and xss (also known as js-xss) are both JavaScript libraries designed to sanitize HTML and prevent cross-site scripting (XSS) attacks. DOMPurify, developed by security firm Cure53, uses the browser's native DOM parser to sanitize content, while xss takes a pattern-matching approach with a whitelist-based filtering system. Both libraries aim to make user-generated content safe for display in web applications, but they differ significantly in their implementation philosophy and runtime environments.

This comparison is relevant for developers building applications that handle untrusted HTML input—from rich text editors and comment systems to email renderers and markdown parsers. DOMPurify primarily targets browser environments (with jsdom support for Node.js), making it ideal for client-side sanitization, while xss was designed with Node.js as a first-class citizen and works seamlessly in both server and browser contexts. Frontend developers working with React, Vue, or Angular will likely encounter DOMPurify, while backend Node.js developers often reach for xss.

Head-to-Head

Sanitization Approach→ dompurify wins

dompurify

Uses native DOM parsing APIs to sanitize HTML. The browser parses the HTML into a DOM tree, then DOMPurify walks the tree removing dangerous elements and attributes. This leverages browser security mechanisms and handles edge cases that regex cannot catch.

xss

Uses regex pattern matching and string replacement with a whitelist approach. Scans the HTML string for known-safe tags and attributes, filtering everything else. More predictable output but can miss novel attack vectors that exploit parser quirks.

Bundle Size→ xss wins

dompurify

Approximately 45-50KB minified, 17-20KB gzipped. Larger because it includes comprehensive HTML5, SVG, and MathML support with extensive configuration options and edge case handling.

xss

Approximately 23KB minified, 8KB gzipped. Significantly smaller footprint due to its string-based approach and more focused feature set. Better choice when bundle size is critical.

Runtime Environment→ xss wins

dompurify

Primarily browser-focused, requires jsdom or similar DOM implementation for Node.js environments. The jsdom dependency adds significant overhead for server-side usage (jsdom itself is several megabytes).

xss

Written for Node.js first with browser support added later. Works natively in both environments without additional dependencies. Better architectural fit for isomorphic/SSR applications.

Configuration Flexibility→ dompurify wins

dompurify

Extensive configuration system with hooks API allowing custom behavior. Supports FORBID_TAGS, ALLOW_TAGS, FORBID_ATTR, ADD_TAGS, and programmatic hooks for custom sanitization logic. Can handle complex requirements like MathML or custom elements.

xss

Configuration through whiteList object defining allowed tags and attributes. Simpler API with onTag, onTagAttr, and onIgnoreTag callbacks. Less granular control but easier to understand for basic use cases.

Security Robustness→ dompurify wins

dompurify

DOM-based parsing means it handles mutation XSS (mXSS) attacks better—cases where HTML becomes dangerous after browser parsing. Maintained by Cure53, a professional security firm, with extensive browser testing and CVE track record.

xss

Regex-based approach can be bypassed with carefully crafted payloads that exploit browser parsing quirks. More vulnerable to mXSS attacks. However, still effective for most common XSS vectors when properly configured.

Performance Characteristics→ xss wins

dompurify

Performance depends on browser's native parser speed. Generally very fast for typical HTML documents. Can be slower with extremely large documents (100KB+) due to DOM tree construction overhead.

xss

String-based operations are consistently fast and predictable across inputs. Better performance with very large documents since it avoids DOM construction. Benchmark roughly 2-3x faster on large inputs.

Verdict

For browser-based applications where security is paramount, DOMPurify is the clear choice. Its DOM-based approach provides superior protection against sophisticated XSS attacks, including mutation XSS vectors that regex-based solutions miss. The larger bundle size is a worthwhile tradeoff for applications handling untrusted rich content, and the extensive configuration options make it adaptable to complex requirements. If you're building a modern single-page application with React, Vue, or Angular, DOMPurify's browser-first design and security pedigree make it the industry standard.

Choose xss for Node.js backend applications, API servers, or situations where bundle size is critical. Its native Node.js support without jsdom dependencies makes it architecturally cleaner for server-side rendering and email generation workflows. The smaller footprint (less than half of DOMPurify when gzipped) matters for edge computing environments or applications with strict performance budgets. While less robust against novel attack vectors, xss provides adequate protection for most use cases when you're sanitizing on the server before storage, especially when combined with Content Security Policy headers.

When to Use Each

If you are building a client-side rich text editor (like Quill or TipTap integration) → use DOMPurify because it runs natively in the browser without dependencies and handles complex HTML5 content including SVG and MathML that users might paste.

If you are building a Node.js API that sanitizes user comments before storing in a database → use xss because it runs natively in Node.js without requiring jsdom, has better performance for batch processing, and the smaller memory footprint matters at scale.

If you are building a React/Vue/Angular application that renders user-generated HTML → use DOMPurify because its DOM-based approach integrates naturally with virtual DOM frameworks and provides maximum security for browser-based threats.

If you are building an edge function or Cloudflare Worker that processes HTML → use xss because the 8KB gzipped size fits comfortably in edge runtime constraints, and you avoid the multi-megabyte jsdom dependency that DOMPurify would require.

Learn More

dompurify →xss →

Head-to-Head

Sanitization Approach→ dompurify wins

dompurify

xss

Bundle Size→ xss wins

dompurify

Approximately 45-50KB minified, 17-20KB gzipped. Larger because it includes comprehensive HTML5, SVG, and MathML support with extensive configuration options and edge case handling.

xss

Approximately 23KB minified, 8KB gzipped. Significantly smaller footprint due to its string-based approach and more focused feature set. Better choice when bundle size is critical.

Runtime Environment→ xss wins

dompurify

xss

Written for Node.js first with browser support added later. Works natively in both environments without additional dependencies. Better architectural fit for isomorphic/SSR applications.

Configuration Flexibility→ dompurify wins

dompurify

xss

Security Robustness→ dompurify wins

dompurify

xss

Performance Characteristics→ xss wins

dompurify

Performance depends on browser's native parser speed. Generally very fast for typical HTML documents. Can be slower with extremely large documents (100KB+) due to DOM tree construction overhead.

xss

Verdict

When to Use Each