Isonomy vs AccessComply: Overlay vs Source-Code Accessibility Fixes for Shopify

The Core Difference Nobody Talks About

Isonomy has impressive social proof: 4.9 stars, 70+ reviews, and a polished App Store presence. If you are evaluating Shopify accessibility apps, Isonomy is probably on your shortlist.

AccessComply is newer. It has fewer reviews. But it takes a fundamentally different approach to making your store accessible: it fixes the theme source, verifies the result, and keeps backup history.

Isonomy is an overlay. It injects JavaScript that modifies your store's DOM at runtime, attempts to fix accessibility issues after the page loads, and provides a widget for users to adjust display settings.

AccessComply is a source-code fixer. It scans your theme with Playwright and axe-core, generates fixes for your Liquid templates and CSS files, and writes those changes directly to your theme through the Shopify API.

The question is: which approach actually makes your store compliant?

What Overlays Do (And Don't Do)

When you install Isonomy, a JavaScript file is added to your store. On every page load, that script:

1. Runs after the browser parses and renders your HTML
2. Scans the DOM for common accessibility issues
3. Attempts to inject fixes (adding ARIA attributes, modifying color values, etc.)
4. Displays an accessibility widget for manual adjustments

This is an overlay. The name comes from the fact that it overlays accessibility fixes on top of your existing code without changing that code.

The Overlay's Fundamental Weakness

Screen readers like JAWS, NVDA, and VoiceOver read your HTML as it exists in the source — or more precisely, as it loads from the server. By the time an overlay script runs, a screen reader may already be processing the page.

More critically: when an overlay script fails — due to an ad blocker, a CDN outage, a JavaScript error, or a user who has disabled scripts — every underlying violation reappears instantly. Your store's actual HTML, your Liquid templates, your CSS — those are unchanged. The compliance exists only while the widget is running.

Overlays and Risk

The risk problem with overlays is practical: the source can remain unchanged, and customers using assistive technology can still hit the same barriers. Multiple ADA complaints have involved websites that had overlay products installed at the time of the alleged violations.

The data supports this. Research found that 22.6% of websites sued for accessibility violations had an overlay installed. Paying for an overlay product did not protect those businesses.

What Source-Code Fixes Do

When you run AccessComply on your store:

1. A headless Playwright browser crawls your store pages and runs axe-core
2. Violations are categorized: deterministic fixes and context-aware fixes
3. For each fixable violation, an agent generates the corrected code
4. Fixes are staged and applied to your theme files via the Shopify GraphQL API
5. A post-fix re-scan verifies that each fix resolved the violation
6. If a fix causes a regression, it is flagged and reverted

The result: your theme files contain the accessible code. There is no widget dependency. The fixes persist even if every JavaScript file on your site fails to load.

Feature Comparison

The Pricing Reality

Isonomy charges a monthly fee for their overlay service. AccessComply also has a monthly subscription — but the pricing model reflects a different value proposition.

With an overlay, you are renting compliance that disappears when you stop paying. The underlying code is never fixed. If you cancel, your store reverts to its original violated state immediately.

With AccessComply, your first fix run makes permanent changes to your theme. Those changes persist whether or not you maintain a subscription. The subscription covers ongoing monitoring, new violation detection as your content changes, and continued access to the AI fix agents.

Who Should Use Each

Isonomy may be sufficient if:

• You are in a low-risk jurisdiction with minimal ADA/EAA exposure
• You need something in place quickly as a temporary measure
• You understand the limitations and plan to do source-code work later

AccessComply is the right choice if:

• You want WCAG 2.1 AA improvements that show up in the served theme source
• You sell to EU customers and need EAA-oriented documentation and ongoing scans
• You have received or fear a demand letter
• You want fixes that persist without a JavaScript dependency

The Accessibility Community's Position

The accessibility community has been clear about overlays for years. The Overlay Fact Sheet has been signed by hundreds of accessibility professionals. The consensus: overlays cannot substitute for manual remediation or source-code fixes.

For Shopify merchants specifically, the distinction matters because your checkout flow is handled by Shopify's native checkout (which you cannot modify with an overlay anyway). AccessComply's approach works within Shopify's actual theme architecture.

Conclusion

Isonomy is a polished product with good reviews. But the reviews mostly reflect ease of installation and customer service, not whether the underlying Shopify theme source has been remediated.

AccessComply fixes the code that generates your pages. That is the approach that gives a merchant something concrete to verify: changed Liquid/CSS, scan results, backups, and a manual-review queue for anything unsafe to automate.

The choice comes down to: do you want the appearance of accessibility, or actual accessibility?

Further Reading

• Why Accessibility Overlay Widgets Don't Work (And What Actually Does)
• AccessComply vs AccessiBe: Source-Code Fixes vs Overlay Widgets
• Sued Despite Having an Overlay: Why 22.6% of ADA Lawsuits Target Sites With Widgets Installed
• What Is the European Accessibility Act (EAA) and How It Affects Shopify Stores