Parity by Taahir
Built at Meta Global AI Developer Hackathon · Oct 26, 2026 · Remote

Most websites are built and tested by people who can see them. A blind person uses the same sites through a screen reader, software that reads aloud what the page’s code says each element is. When the code and the picture disagree, the sighted customer and the blind customer are on two different sites. On the checkout I built to show this, a green button reads “Pay R1,249” on screen while the screen reader announces “Submit”: the shopper cannot tell what they are about to be charged. Four stars under a product are pixels that announce nothing. A red border is the only sign of an error. This is common and expensive. 95.9% of the top million home pages have detectable WCAG failures (WebAIM, 2026). In 2025, 5,114 digital-accessibility lawsuits were filed in the US, 70% against e-commerce sites (UsableNet); one small retailer paid about $46,000 in legal fees and $13,000 to fix its sites (WSJ, 2024). Since June 2025 the EU Accessibility Act covers e-commerce, with fines up to €100,000 in Germany. Today’s tooling is the rule engine. axe-core, the most widely used, scans a page’s code against a list of rules: a missing alt attribute, a field with no label. It is fast and free, and it cannot see the page. In a UK government test the best of ten automated tools caught 41% of a page’s barriers (GDS, 2017). On my demo store, with 38 seeded barriers, axe-core reports 0 violations, because every one is a disagreement between what is seen and what is announced, which no rule can detect. Parity is for the team shipping that checkout. Its job, before a release: find what stops a blind shopper from completing the purchase, prove each barrier with evidence, and fix it. Push the Frontier, in software: Parity gives an agent a new sense, to see a page as a sighted shopper and hear it as a screen reader, and to prove where they differ. One agent, Muse Spark with Meta’s computer-use tool, walks the flow from product to order confirmation. On each screen, Spark’s perception grounding marks what a sighted user sees, and a second Spark call reads the screenshot against the accessibility tree and quotes where they disagree. Then code decides: six checks gate every claim, a judge rates severity against WCAG, a fixer proposes the smallest HTML change, a sandboxed re-audit confirms the screen reader now says what the screen shows, and a human approves each fix and downloads one patch. Real VoiceOver audio, transcribed by Muse Voice Transcribe, is the evidence beside the tree. The result: an audit for cents and minutes where a manual review costs $100–$250 a page (vendor pricing, 2026), catching the barrier before release instead of after the lawsuit, the fine or the lost sale, for a customer who otherwise clicks away (69% do; Click-Away Pound, 2019). On my store it finds 85% of the seeded barriers at 99% precision. Findings are evidence, never a conformance claim; nothing is applied without a person.