Free API + MCP server — no key

Build with the front desk.

Three endpoints straight from Lobby's production receptionist stack — AI phone scripts in English and Mexican Spanish, ElevenLabs agent system prompts, and missed-call math. Plain HTTPS, no key, no signup. And an MCP server, so your AI agents can call all of it as tools.

Quickstart

One curl. No auth.

Write a phone script

curl -X POST https://lobbyvoices.com/api/v1/phone-script \
  -H 'content-type: application/json' \
  -d {"mode":"voicemail","business":"Vargas Plumbing","trade":"plumbing","langs":["en","es"]}

Generate an ElevenLabs agent prompt

curl -X POST https://lobbyvoices.com/api/v1/agent-prompt \
  -H 'content-type: application/json' \
  -d {"biz":"Vargas Plumbing","industry":"plumbing","tasks":["book","faqs"],"hours":"Mon-Sat 8am-6pm","spanish":true,"tone":"warm"}

Price a missed-call problem

curl -X POST https://lobbyvoices.com/api/v1/missed-call-cost \
  -H 'content-type: application/json' \
  -d {"callsPerWeek":75,"missedRatePct":33,"avgJobValue":380}

Endpoints

Three endpoints, zero ceremony.

POST/api/v1/phone-scriptAI writes a greeting, voicemail, on-hold message, or jingle lines — English, Spanish, or both.

POST/api/v1/agent-promptA production-grade system prompt for an ElevenLabs agent: identity, booking flow, guardrails, escalation.

POST/api/v1/missed-call-costMonthly and yearly revenue lost to missed calls, plus recovery math and break-even.

Machine-readable spec: /api/v1/openapi.json

MCP

Give your agent the toolkit.

Connect the MCP server and your agent can write phone scripts, generate ElevenLabs prompts, and price missed calls on its own — same endpoints, no key.

Claude Code

claude mcp add --transport http lobbyvoices https://lobbyvoices.com/api/mcp

Cursor · Claude Desktop · any MCP client

{
  "mcpServers": {
    "lobbyvoices": { "url": "https://lobbyvoices.com/api/mcp" }
  }
}

Tools your agent gets

write_phone_scriptGreeting, voicemail, on-hold, or jingle copy in EN, es-MX, or both.

write_ivr_menuA complete IVR phone-menu script — greeting, numbered options, Spanish switch, operator line.

generate_elevenlabs_agent_promptA complete receptionist system prompt for ElevenLabs agents.

calculate_missed_call_costThe leak, the recovery, and the break-even — as structured numbers.

should_i_hire_a_receptionistA coverage verdict with archetype, yearly leak, break-even and ROI.

Fair use

Free, within reason.

No key, no signup. Per-IP rate limits (roughly 30 requests a minute per endpoint) and hard input caps keep the service healthy. Building something bigger on top of it? Tell us — we like builders. Contact us

The next step

The API is free. The receptionist answers for you.

Lobby is the AI front desk behind these endpoints — it answers every call, books the job, and speaks English and Spanish, 24/7.

Meet your receptionist