Auphonic

Auphonic is a cloud service that automates audio post-production for podcasts and other spoken-word recordings. It runs uploaded audio through algorithms that normalize loudness to broadcast standards, remove background noise and hum, level out volume differences between multiple speakers or microphones, and cut silences, producing a mastered file without the need for manual work in a DAW. It also handles tasks like generating chapter markers, adding intro and outro music, filling in ID3 tags, and exporting to multiple formats and bitrates in one pass.

It's built for podcasters, radio producers, and anyone recording interviews or multi-track conversations who wants consistent, professional-sounding audio without learning mixing and mastering by hand. Users can work through the web interface, hook into the production workflow via a REST API, or connect Auphonic to recording and hosting tools so files are processed and published automatically. The multitrack algorithm in particular is useful for shows recorded with separate tracks per speaker (common with remote interview setups), since it can balance and clean each track individually before combining them.

What sets it apart is its narrow focus: rather than being a general audio editor, it does one job, automated mastering, very well, and has done so for long enough (since 2011) to be a known quantity among independent podcasters and small production teams. It integrates with hosting platforms and services like Dropbox, YouTube, and various podcast hosts, making it a piece of plumbing in a workflow rather than a standalone editing app.