Podmotion

Turn YouTube videos, web articles, and text into AI-generated podcasts.

Podmotion is an open-source AI podcast generator. Paste a YouTube URL, drop in a web link, or type raw text — Podmotion extracts the content, summarizes it, writes a multi-speaker script with emotion annotations, and synthesizes natural-sounding audio via TTS.

Features

Multiple input sources — YouTube videos, web pages, or plain text
AI-powered summarization — Streaming summary generation via Google Gemini
Multi-speaker scripts — 1 or 2 speakers with character-level emotion marks (8 types x 4 intensities)
3 podcast styles — Casual chat, popular science, news brief
40+ TTS voices — English and Chinese (Mandarin), with gender filters and voice previews
Editable scripts — Refine paragraphs before generating audio
Per-paragraph audio — Generate and preview audio for each section independently
Agent chat mode — Conversational AI flow for end-to-end podcast creation
Internationalization — English and Simplified Chinese UI
Optional invite gate — Access control via invitation codes

Tech Stack

Layer	Technology
Framework	Next.js 16 (App Router), React 19, TypeScript (strict)
State	Jotai
Styling	Tailwind CSS, shadcn/ui
AI	Vercel AI SDK v6, Google Gemini (via AI Gateway)
TTS	MiniMax (`speech-2.8-turbo`)
Transcripts	Supadata
Testing	Vitest
Package Manager	pnpm

Getting Started

Prerequisites

Node.js 18+
pnpm

Installation

git clone https://github.com/zhanghao/podmotion.git
cd podmotion
pnpm install

Environment Variables

Copy .env.example and fill in your API keys:

cp .env.example .env.local

Variable	Description
`AI_GATEWAY_API_KEY`	Vercel AI Gateway key (for Gemini LLM access)
`SUPADATA_API_KEY`	Supadata key (YouTube transcript extraction)
`MINIMAX_API_KEY`	MiniMax key (TTS audio synthesis)
`INVITE_CODE`	(Optional) Set to enable invitation code gate

Development

pnpm dev          # Start dev server (Turbo mode)

Open http://localhost:3000.

Build

pnpm build        # Production build
pnpm start        # Start production server

How It Works

YouTube URL / Web URL / Text
        │
        ▼
  ┌─────────────┐
  │  Extract     │  Supadata (YouTube) / Web scraper / Direct text
  │  Content     │
  └──────┬──────┘
         │
         ▼
  ┌─────────────┐
  │  AI Summary  │  Google Gemini via streaming
  └──────┬──────┘
         │
         ▼
  ┌─────────────┐
  │  Script Gen  │  Multi-speaker script with emotion marks (NDJSON stream)
  └──────┬──────┘
         │
         ▼
  ┌─────────────┐
  │  TTS Audio   │  MiniMax per-paragraph synthesis with emotion control
  └──────┬──────┘
         │
         ▼
  ┌─────────────┐
  │   Export     │  Final podcast assembly
  └─────────────┘

Project Structure

app/
  [locale]/              # i18n routes (en, cn)
    agent/               # AI agent chat interface
    invite/              # Invitation code gate
  api/                   # Server API routes
    transcript/          # YouTube transcript extraction
    scrape/              # Web page extraction
    summary/             # Streaming AI summary
    script/              # Streaming script generation (NDJSON)
    audio/               # TTS audio synthesis
    agent/               # Agent tool orchestration
    voices/              # Available TTS voices

components/
  agent/                 # Agent chat UI
  preview/               # Content preview + config
  workspace/             # Script editor + audio generation
  ui/                    # shadcn/ui components

hooks/                   # Business logic orchestration
lib/
  atoms/                 # Jotai state definitions
  services/              # Pure async service functions
  utils/                 # Pure utility functions
  prompts/               # AI prompt templates

languages/               # i18n translations (en.json, cn.json)
public/audio/previews/   # Voice preview audio files

Architecture

Five-layer architecture with one-way dependencies:

UI (components/) → Hooks (hooks/) → Atoms (lib/atoms/) + Services (lib/services/) → Utils (lib/utils/)

Scripts

pnpm dev              # Dev server (Turbo mode)
pnpm build            # Production build
pnpm lint             # ESLint
pnpm lint:fix         # Auto-fix lint issues
pnpm type-check       # TypeScript check
pnpm format           # Prettier format
pnpm test             # Vitest watch mode
pnpm test:run         # Single test run
pnpm test:coverage    # Coverage report

License

MIT

Yukiniro/podmotion

README