Translated Subtitles
Let viewers pick their own language for a video's captions.
What it adds
Additional caption tracks in other languages, generated from the source track and selectable in the player.
What your agent is told to do
5
What your agent is told to do
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Translate cue by cue from the corrected source caption track, not from the raw audio, so timing and sentence boundaries are already settled before translation begins.
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Reuse the app's existing AI Translation path and its language list rather than introducing a second translation configuration. This feature adds tracks and player selection, not a new translation engine.
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Offer only the languages the audience actually uses. Generating twenty tracks per video costs real money and buries the two that matter in a long player menu.
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Default the player's caption selection to the viewer's own language preference where a track exists, using the app's existing Locale and Language Switcher setting rather than guessing from the browser alone.
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Do not present machine translations as authoritative. Label them, and allow a human-reviewed track to replace one without regenerating the rest.
Edge cases it handles
8
Edge cases it handles
8- Translated text is routinely longer than the source. Keep the original cue timings but split overlong cues across the available window rather than letting text overflow the screen or get truncated.
- When a viewer requests a language with no track, fall back to the source language with a visible note rather than showing an empty caption area or silently turning captions off.
- Right-to-left languages need correct text direction, alignment, and punctuation placement in the caption renderer. Left-aligned mirrored text is worse than no track.
- Editing the source track must invalidate the translations derived from it, so a corrected name in the original does not persist as the wrong name in five other languages.
- Cache translations per cue and re-translate only the cues whose source text changed. Re-running the whole track on every edit is slow and expensive for no benefit.
- Proper nouns, product names, and code identifiers should be protected from translation, or the captions will helpfully translate the name of the app.
- Track language codes must include region where it matters, so two variants of the same language do not collide in the player menu.
- Generation runs as a background job with progress, and a failure on one language must not block the others.
Definition of done
9
Definition of done
9- Viewers can select from the available caption languages in the player.
- Cue timings are preserved and overlong translations are split rather than clipped.
- A missing requested language falls back to the source track with a visible notice.
- Right-to-left languages render with correct direction and alignment.
- Editing the source track invalidates the derived translations.
- Regeneration re-translates only the cues whose source changed.
- Machine-translated tracks are labelled and can be superseded by a reviewed version.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Auto Captions
Auto Captions
Every uploaded video gets timed captions without anyone typing them out.
What it does
An automatic captioning pass over uploaded video that produces a timed caption track shown in the player.
How it works
- 1 Extend the app's existing Voice Transcription rather than adding a second speech pipeline. What is new here is timing, storage as a caption track, and player integration, not the recognition itself.
- 2 Run captioning as a background job triggered after the upload finishes, and reuse the app's existing job progress reporting so the user can see where a long file has got to.
- 3 Store the caption track as its own record linked to the media, with a language, a status, and a source marking it as machine-generated so a human correction can supersede it later.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/auto-captions
Accessible Name Validator
Accessible Name Validator
Find every control a screen reader announces as nothing useful.
What it does
An audit of the computed accessible name of each interactive element in the rendered interface.
How it works
- 1 Compute the name the way assistive technology does — following the resolution order through labels, referenced elements, attributes, and text content — rather than reading the source markup and guessing.
- 2 Report three separate failures: an empty name, a generic name such as button, link, or here, and duplicate names within the same context where several controls announce identically.
- 3 Prefer a fix that adds a visible label. A control given a hidden name is announced but still mysterious to the sighted user who cannot tell two identical icons apart.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/accessible-name-validator
Touch Target Checker
Touch Target Checker
Find the controls that are too small or too crowded to hit reliably on a phone.
What it does
A development-time audit reporting the measured hit area and neighbour spacing of every interactive element.
How it works
- 1 Measure the element's actual activation area — the region that responds to a tap — rather than the icon or glyph drawn inside it, since padding and pseudo-element extensions frequently make a small icon a perfectly adequate target.
- 2 Check the gap between adjacent targets as well as their size. Two comfortable buttons sitting flush against each other still produce mis-taps, and the report must say which of the two problems it found.
- 3 Report the offending elements with enough context to locate them — the route, the component, and a way to highlight the element on the page — rather than a count of failures.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/touch-target-checker
How it works
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Copy the link
Grab the Markdown instruction URL for this feature.
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Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.