Build an Audio Trimmer with Claude Code

Build an Audio Trimmer web app. People search for "audio trimmer" about 72,000 times a month, plus related searches like "cut audio online", "trim mp3 file", "audio cutter free". The goal is a tool that ranks for those searches and makes money.

What it should do:
Build an audio trimmer web app. Create a homepage with a large upload zone saying 'Drop your audio file to trim'. When users upload audio, show a waveform visualization with draggable start and end markers. Add play/pause controls and zoom in/out functionality. Include precise time input fields (mm:ss.ms format) and a preview section that plays only the selected portion. Show file format options for download (MP3, WAV, AAC) and quality settings. Use a clean design with purple and blue audio-themed colors. Focus on the upload and trimming interface first.

How to build it:
1. Read this folder first. If it is empty, set up Next.js (App Router, TypeScript, Tailwind). Write a short PLAN.md with the pages, components, any library or API you need, and what you are leaving for later. Then build.
2. Put the tool itself on the homepage so a visitor can use it within seconds, with no sign-up. Do the processing in the browser where you can, so it is fast and cheap to run. Look at how Online Audio Cutter, MP3Cut, Audacity do it and make ours simpler and faster.
3. Make it rank. Use "audio trimmer" in the title tag, H1 and meta description. Under the tool, add a short how-to and an FAQ with FAQPage schema, and add a sitemap and robots.txt. Scaffold these programmatic pages from one template and a data file: /trim-[audio-format]-files, /audio-trimmer-for-[use-case], /cut-audio-[duration].
4. Monetisation: Freemium: 10min audio files, $6/mo unlimited + HD quality. Add a pricing page and the free usage limit, and leave Stripe checkout as a clearly marked stub with the environment variables it needs.
5. Run it locally and test the main flow end to end, including edge cases like empty input and very large files. Fix what breaks, then finish with a summary of what works, what is stubbed and how to deploy it to Vercel.

Paste it into Claude Code in an empty folder. It plans first, so read PLAN.md and steer before it starts building.