How Cybozu Eliminated Browser Compatibility Overhead with Baseline

Discover how Cybozu, a leading Japanese groupware company serving 38,000+ enterprise customers, replaced manual browser version tracking with the Baseline standard to streamline development and improve security.

How Cybozu Eliminated Browser Compatibility Overhead with Baseline

The Challenge: Browser Support Guesswork

Managing browser compatibility for over 38,000 enterprise customers across Japan isn't trivial. When Kintone powers critical business operations for over 1.5 million applications daily, every browser support decision matters.

Cybozu, a leading groupware company in Japan, faced a fundamental challenge: How to maintain consistent web standards across products while avoiding the maintenance burden of custom browser support matrixes.

The Old Approach: User-Agent Based Tracking

Before Baseline, Cybozu maintained their own browser support criteria based on access logs and manual version tracking. Their standard was to support browsers covering the top 98% of access logs.

Problems with this approach:

  • Every quarter, engineering teams spent hours updating criteria
  • Questions constantly arose: When can new CSS features be used? When can polyfills be removed?
  • User-Agent strings are unreliable - bots, crawlers, and attackers skew the data
  • Browser versions don't map directly to features
  • The Security Risk

    Supporting outdated browsers doesn't just mean missing out on new features - it's about failing to protect users. Outdated browsers contain known security vulnerabilities. By supporting them based solely on access logs, Cybozu was potentially enabling users to remain vulnerable.

    Why Baseline Was the Answer

    Baseline provided exactly what Cybozu needed:

    1. Externally Maintained, Evolving Criteria

    Instead of manually reassessing browser versions every quarter, Baseline provides a moving target maintained by the W3C WebDX Community Group. The criteria automatically evolve with input from browser vendors and standards bodies.

    2. Feature-Level Precision

    Baseline Widely Available represents web features available for 30+ months across major browsers. This eliminates guesswork - "Can we use CSS container queries?" becomes an instantly answerable question.

    3. Security-Conscious by Design

    By adopting Baseline Widely Available, Cybozu aligned their support policy with browser vendors' support lifecycles. Browsers that are actively maintained support all Widely Available features while receiving security updates.

    Measuring the Impact

    Before adoption, Cybozu needed confidence that Baseline would work without significant drawbacks. Using the Google Analytics Baseline Checker tool, they discovered:

    98.8% of their users were on Baseline-compatible browsers - actually higher than their previous 98% threshold!

    Practical Implementation

    Static Analysis with ESLint

    Using the eslint-plugin-baseline package, developers get immediate feedback when they attempt to use features outside the Baseline threshold:

    ``javascript

    // .eslintrc.js

    module.exports = {

    plugins: ['baseline'],

    rules: {

    'baseline/no-non-baseline-features': ['error', {

    available: 'widely'

    }]

    }

    };

    `

    Transpiler Configuration

    Setting Browserslist to target Baseline ensures transpilers like Babel and bundlers automatically handle compatibility:

    `

    # .browserslistrc

    baseline widely available

    ``

    Eliminated Manual Maintenance

    The browser update prompt system that previously required manual version updates now simply checks Baseline compatibility. Zero maintenance required.

    Key Takeaways

  • User-Agent is unreliable - Don't base support decisions on easily spoofed data
  • Version numbers ≠ features - The same version can have different capabilities
  • Supporting old browsers = enabling vulnerabilities - Security must be considered
  • Baseline removes guesswork - Clear, externally-maintained standards
  • 98.8% coverage achieved - Higher than the manual 98% threshold
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    > Source Attribution: This content is adapted from the case study "How Cybozu eliminated browser compatibility overhead with Baseline" published on web.dev under the Creative Commons Attribution 4.0 License. Original authors: Sakura Adachi, Yuriko Hirota.