#!/usr/bin/env bash
set -euo pipefail

MODEL="openai/gpt-4o-mini-tts-2025-12-15"
VOICE="alloy"
FORMAT="mp3"                          # mp3 or pcm
INPUT="Hello! This is a text-to-speech test."
OUTPUT="speech-$(date +%Y%m%d-%H%M%S).${FORMAT}"
HEADERS=$(mktemp)

payload=$(jq -n --arg model "$MODEL" --arg input "$INPUT" \
               --arg voice "$VOICE" --arg fmt "$FORMAT" \
  '{model: $model, input: $input, voice: $voice, response_format: $fmt}')

http_code=$(curl -sS -X POST https://openrouter.ai/api/v1/audio/speech \
  -H "Authorization: Bearer $OPENROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -D "$HEADERS" \
  --output "$OUTPUT" \
  -w '%{http_code}' \
  -d "$payload")

if [[ "$http_code" != "200" ]]; then
  echo "TTS failed (HTTP $http_code):" >&2
  cat "$OUTPUT" >&2                   # error body is JSON, not audio
  rm -f "$OUTPUT" "$HEADERS"
  exit 1
fi

gen_id=$(grep -i '^x-generation-id:' "$HEADERS" | awk '{print $2}' | tr -d '\r')
rm -f "$HEADERS"
echo "Saved $(realpath "$OUTPUT") (generation_id=${gen_id:-unknown})"

undefined

Voices are provider-namespaced: OpenAI uses short names (`alloy`, `nova`), Voxtral encodes language + persona + emotion (`en_paul_happy`), Kokoro prefixes with language/gender (`af_bella` = American female Bella).

{
  "model": "openai/gpt-4o-mini-tts-2025-12-15",
  "input": "Welcome to the show.",
  "voice": "alloy",
  "response_format": "mp3",
  "provider": {
    "options": {
      "openai": {
        "instructions": "Speak in a warm, friendly tone with a slow pace."
      }
    }
  }
}

undefined

```typescript
// TypeScript — collect bytes, write once
import OpenAI from "openai";
import fs from "fs";

const client = new OpenAI({
  baseURL: "https://openrouter.ai/api/v1",
  apiKey: process.env.OPENROUTER_API_KEY!,
});

const response = await client.audio.speech.create({
  model: "openai/gpt-4o-mini-tts-2025-12-15",
  input: "The quick brown fox jumps over the lazy dog.",
  voice: "nova",
  response_format: "mp3",
});

await fs.promises.writeFile(
  "output.mp3",
  Buffer.from(await response.arrayBuffer()),
);