Vibe Coding Charts? 10 Accessibility Mistakes Your AI Is Making

Color-Only Encoding

This is the single most common accessibility failure in charts. When color is the only way to tell data series apart, anyone with color vision deficiency is left guessing. And it is not a small group: deuteranomaly (difficulty distinguishing red and green) alone affects 2.3% of the global population.

The pie chart below uses five shades of red. On a normal monitor, you might be able to squint and tell them apart. Through the eyes of someone with protanopia or deuteranopia, these slices are functionally identical.

Don't: Similar colors, no labels

Do: Distinct colors, data labels

Low Contrast Ratios

WCAG requires a minimum contrast ratio of 3:1 for graphical elements and 4.5:1 for text. But chart libraries often ship with default color palettes that were designed to look "modern" and "clean" rather than to be readable. Light grays on white backgrounds, pastel-on-pastel combinations, thin lines that blend into the grid, all of these fail basic contrast requirements.

The chart below is an extreme (but not uncommon) example. Light gray bars, light gray text, light gray legend items on a white background. It looks "sleek" to the designer who made it. It is functionally invisible to anyone with low vision, and it is difficult to read for everyone on a bright screen or cheap monitor.

Don't: Ghost chart

Do: Strong contrast + data labels

Missing or Inadequate Alt Text

Screen readers cannot interpret pixels. When a chart image has alt="" or alt="Chart" or, worse, no alt attribute at all, a screen reader user gets zero information. This is a Level A failure, the most basic level of WCAG compliance, and it is shockingly common.

The fix is not just slapping a one-liner on the image tag. Good alt text for charts needs to convey the insight, not just describe the chart type. There is a big difference between "Bar chart of sales data" and "Bar chart showing 75% revenue growth from Q1 ($1.2M) to Q4 ($2.1M) in 2025, with consistent quarterly increases."

<!-- Bad -->
<img src="chart.png" alt="Chart">

<!-- Good -->
<figure>
  <img src="chart.png"
       alt="Bar chart: Revenue grew 75% from Q1 ($1.2M) to Q4 ($2.1M) in 2025">
  <figcaption>
    Revenue increased each quarter, with the steepest jump (+$300K)
    occurring between Q2 and Q3. All four regions contributed to growth.
  </figcaption>
</figure>

No Keyboard Navigation

If your chart has interactive features (tooltips, drill-downs, zoom, filter controls) that only work with a mouse, you have locked out every user who navigates by keyboard. This includes people with motor disabilities, users with tremors or arthritis, voice control users, and power users who simply prefer the keyboard.

This is another Level A failure. If someone cannot tab to a data point and press Enter to see its details, the interactive functionality does not exist for them.

<!-- Interactive SVG chart element with keyboard support -->
<g role="img" aria-label="Interactive bar chart with 4 data points">
  <rect tabindex="0"
        role="button"
        aria-label="Q1 Revenue: $1,200,000"
        onfocus="showTooltip(this)"
        onblur="hideTooltip(this)"
        onkeydown="handleArrowKeys(event)">
  </rect>
</g>

If you are using a charting library, check whether it ships with an accessibility module. Highcharts, for example, includes a built-in accessibility module that handles keyboard navigation, screen reader announcements, and focus management out of the box when enabled.

Missing Data Tables as Alternatives

A chart is a visual encoding of data. If you only provide the visual encoding and not the underlying data, you are forcing users to estimate values from pixel positions. That is imprecise for sighted users and impossible for screen reader users. A companion data table gives everyone access to exact values.

This does not mean you need to clutter your page with a massive table under every chart. A collapsible "View data table" link or a download option works perfectly. The point is that the data must be available in a non-visual format.

<!-- Collapsible data table for a chart -->
<details>
  <summary>View data table</summary>
  <table>
    <thead>
      <tr>
        <th scope="col">Quarter</th>
        <th scope="col">Revenue (USD)</th>
        <th scope="col">Growth</th>
      </tr>
    </thead>
    <tbody>
      <tr><td>Q1 2025</td><td>$1,200,000</td><td>+5%</td></tr>
      <tr><td>Q2 2025</td><td>$1,500,000</td><td>+25%</td></tr>
      <tr><td>Q3 2025</td><td>$1,800,000</td><td>+20%</td></tr>
      <tr><td>Q4 2025</td><td>$2,100,000</td><td>+17%</td></tr>
    </tbody>
  </table>
</details>

Legend-Only Labeling

Legends force users into a constant lookup loop: look at the line, check its color, scan the legend, match the color, go back to the line, and repeat. This is cognitively expensive for everyone and disproportionately difficult for users with color vision deficiency, short-term memory challenges, or attention deficits.

The chart on the left relies entirely on the legend. The chart on the right uses direct labels at the end of each line, plus different line styles and marker shapes so you can tell them apart even without color.

Don't: Legend-only, identical line styles

Do: Direct labels, varied styles

Overcrowded Charts

There is a temptation to pack as much data as possible into a single chart. Twelve series on one line chart, fifty data points with overlapping labels, twenty slices in a pie chart. The result is visual noise that no one can parse, and for screen reader users, it becomes a wall of announcements that is functionally useless.

The chart on the left has 12 series jammed into one view. The chart on the right shows the top 3 sources clearly, with a subtitle noting that the remaining 9 sources account for 38% of traffic. Same data story, dramatically better comprehension.

Don't: 12 series, visual spaghetti

Do: Top 3 sources, clear story

Missing Axis Labels and Units

A chart titled "Data" with bars labeled A through E and a Y-axis showing numbers without units is meaningless. Are those dollars? Thousands of users? Percentage points? Metric tons? Without axis labels and units, the viewer is left to guess, and a guess is not data communication.

This mistake is especially harmful for screen reader users, who only get the text content. If the axis label says nothing, the screen reader says nothing useful either.

Don't: "Data" with mystery values

Do: Descriptive title, clear units

Visual-Only Trends

A line sloping upward. A cluster of dots in the top-right corner. A seasonal wave pattern. These visual trends are obvious to sighted users, but they are invisible to screen reader users and inaccessible to anyone who cannot perceive visual patterns.

The fix is simple: describe the trend in text. A one-sentence summary below the chart that says "Revenue grew 75% from Q1 to Q4, with the steepest increase between Q2 and Q3" makes the insight available to everyone. This also benefits sighted users who might miss subtle patterns or misinterpret the data.

<figure>
  <img src="sales-chart.png"
       alt="Line chart showing quarterly sales growth in 2025"
       aria-describedby="chart-summary">
  <div id="chart-summary" role="region" aria-label="Chart summary">
    <p>Revenue grew 75% from $1.2M (Q1) to $2.1M (Q4). Growth was
    consistent across quarters, with the largest single-quarter
    increase of $300K between Q2 and Q3.</p>
  </div>
</figure>

Animation Without Reduced-Motion Support

Bars that slide in from the bottom, pie slices that spin into place, data points that bounce onto the screen. Chart animations feel polished, but for roughly 15% of the population who have some sensitivity to motion, they cause real physical symptoms: dizziness, nausea, migraines, and in extreme cases, seizures.

The prefers-reduced-motion media query has been supported in all major browsers since 2019. There is no excuse for ignoring it.

/* CSS: Respect reduced-motion preferences */
@media (prefers-reduced-motion: reduce) {
  .chart-element,
  .chart-element * {
    animation: none !important;
    transition: none !important;
  }
}

/* JavaScript: Check before animating */
const prefersReducedMotion = window.matchMedia(
  "(prefers-reduced-motion: reduce)"
).matches;

const chartOptions = {
  plotOptions: {
    series: {
      animation: prefersReducedMotion ? false : { duration: 600 }
    }
  }
};

Quick Reference

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The Bottom Line

Vibe coding is not going away. The speed advantage is real, and the developer experience is compelling. But the speed advantage is worthless if 15% of your users cannot use the output.

Seven of these ten errors violate WCAG Level A or AA requirements. These are not aspirational best practices; they are the legal baseline in the EU under the European Accessibility Act (effective June 2025) and in the US under ADA and Section 508 interpretations.

The good news is that none of these fixes are difficult. Most of them take less time than designing the chart in the first place. Use distinct colors and add text labels. Bump your contrast ratios. Write alt text that describes the insight. Provide a data table. Label your axes. Describe your trends in words. Check a single media query before animating.

When you are generating charts with AI, audit the output against these ten errors. Add a checklist to your code review. If you are prompting the AI, add accessibility requirements to your prompts. "Generate a chart..." should become "Generate an accessible chart with distinct colors, direct labels, a data table, and alt text describing the trend."

Accessible charts are not just compliance checkboxes. They are better charts, period. A chart that works for a colorblind user also works better for the person projecting it on a washed-out conference room screen. A chart with direct labels is faster to read for everyone. A chart with a textual summary is more persuasive in an email where the image might not load.

Build for the widest audience, and the quality follows.