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ElevenLabs Voice

The most realistic AI voice, paid per call in USDC.

Give your agent a voice. ElevenLabs text-to-speech and sound effects behind x402 — Flash v2.5 for real-time conversation, Multilingual v2 / Eleven v3 for studio-grade narration. Price is quoted up front, you pay only after the audio is generated, and there's no subscription to manage.

HOW IT WORKS

Send text to /v1/audio/speech; the server returns a 402 with the exact price (characters × model rate). Sign the USDC payment, replay the request, and get back a hosted audio URL. Flash starts at $0.05/1k chars, minimum $0.001 per request.

3 endpoints live on Base
32 languages
~75ms latency (Flash)
No account required
ElevenLabsElevenLabs Docs

What Agents Use It For

Anywhere your agent needs to speak — voice assistants, narration, IVR, accessibility, game and video audio — without standing up a TTS pipeline or committing to a monthly plan.

Real-Time Agent Voice
Flash v2.5 synthesizes speech at ~75ms latency — the voice your agent speaks with in real time. 32 languages, deterministic per-character pricing.
Studio-Grade Narration
Multilingual v2 and Eleven v3 deliver maximum consistency and emotional range for audiobooks, voiceover, and long-form content.
Cinematic Sound Effects
Generate sound effects and audio textures from a text prompt — explosions, ambience, UI sounds, foley — up to 22 seconds per clip.
Pay-per-Call, No Accounts
Every call settled in USDC via x402 on Base. No ElevenLabs subscription, no API keys for callers — just attach payment to the request.

Models & Pricing

Text-to-speech is billed per input character (quoted before you pay). Sound effects are flat per generation. A 5% platform fee and a $0.001 per-request minimum apply.

ModelPriceMax inputBest for
elevenlabs/flash-v2.5$0.05 / 1k chars40,000Ultra-low-latency (~75ms) speech synthesis for real-time voice agents. 32 languages.
elevenlabs/turbo-v2.5$0.05 / 1k chars40,000Balanced quality and latency (~250ms) for interactive use cases. 32 languages.
elevenlabs/multilingual-v2$0.10 / 1k chars10,000Highest-consistency voice for long-form narration, audiobooks, and voiceover. 29 languages.
elevenlabs/v3$0.10 / 1k chars5,000Maximum expressiveness and emotional range for creative applications. 70+ languages.
elevenlabs/sound-effects$0.05 / clip22sGenerate cinematic sound effects and audio textures from a text prompt (up to 22s).

Quick Start

01

Pick a voice (free)

curl https://blockrun.ai/api/v1/audio/voices
# -> { "data": [ { "voice_id": "EXAVITQu4vr4xnSDxMaL", "alias": "sarah", ... }, ... ] }
02

Synthesize speech (pay per call)

Send unpaid to get a 402 with the exact price, then replay with the signed x-payment header.

curl -X POST https://blockrun.ai/api/v1/audio/speech \
  -H "Content-Type: application/json" \
  -d '{
    "model": "elevenlabs/flash-v2.5",
    "input": "Hello from BlockRun. Pay per call, no subscription.",
    "voice": "sarah",
    "response_format": "mp3"
  }'

# Response (after settlement):
# {
#   "model": "elevenlabs/flash-v2.5",
#   "data": [{ "url": "https://blockrun.ai/api/media/media/audios/...mp3",
#              "format": "mp3", "characters": 51 }]
# }

Use From Your Tooling

Claude Code / Cursor (MCP)

Install once, then ask: "use blockrun to speak this with the sarah voice."

claude mcp add blockrun -s user -- \
  npx -y @blockrun/mcp@latest
Python / TypeScript SDK

Wallet loaded from ~/.blockrun/.session. SDK handles 402 + signing.

pip install blockrun-llm
# or
npm install @blockrun/llm

Behind the Scenes

ElevenLabs

Powers the voice synthesis and sound generation. BlockRun holds the ElevenLabs API key server-side and covers the upstream cost — you pay per call in USDC, with no subscription.

elevenlabs.io

Get Started

All you need is a USDC-funded wallet on Base. Hit any endpoint, get a 402, attach payment, get the audio.

View DocsView on GitHub