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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 from your input length, settlement happens only after the audio is generated, and there's no ElevenLabs 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 --transport http \
  https://mcp.blockrun.ai/mcp
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