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Live on Cloudflare Workers — sub-200ms cold start

AI voice agents, ready in minutes

Pair a Liquid script with a voice and an LLM. Let the agent run the call end-to-end — or pick up yourself in copilot mode and let it feed you the lines. No infrastructure to run.

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natter.ai/scripts/sales-discovery
Script body
You are calling {{ name }} on behalf of
{{ businessName | default: "Acme" }}.

Objective: {{ objective }}.

Keep replies short and conversational.
Match the caller's language — Mandarin,
Spanish, French, or English.
Variables
{{ name }}
Alice Chen
{{ objective }}
book a demo
{{ businessName }}
Acme Corp
Voice
Xiaoxiao · Azure Multilingual
< 200ms
Edge cold start
60s
New agent to live
99 langs
Auto-detected
5 modes
Per inbound number

Built for

Real calls, real outcomes

Outbound sales

Qualify leads before a human picks up. Drop a list, set a script, the agent dials. Full transcript and outcome on every call.

2 min to live

Inbound support 24/7

Answer in a voice that matches your brand. Caller-id routing sends VIPs to a different agent; everything else gets handled.

No queue

High-stakes calls with copilot

You make the call — the agent listens and feeds you one short sentence at a time. The human voice is yours, the brief is theirs.

Live notes on screen

How it works

Live in three steps

No telephony experience needed. We handle the carriers, the SIP, and the orchestration.

01

Write the script

Author once in YAML + Liquid. Variables fill in per call. Save, version, reuse.

02

Pick a voice + model

Pair the script with your favorite voice and LLM. Swap independently any time.

03

Place the call — or take one

Run it fully autonomous on outbound jobs and inbound traffic, or hop on in copilot mode and read the lines the agent writes. Transcripts land live either way.

What's in the box

Everything you need to ship a voice agent

Multilingual out of the box

Whisper v3 + Gemini Live respond in 99 languages. The agent auto-detects the caller and switches mid-call — no language toggle, no config.

Voices that sound human

Azure neural voices and Gemini Live native audio. Pick one per agent and swap any time without rewriting your scripts.

Copilot mode

You take the call, the agent listens and writes the line for you to read aloud — one short sentence, in your voice, grounded in the call objective. Best of both worlds when full autonomy is too risky.

Five-mode inbound

Per-number routing: AI agent, browser softphone, AI copilot assist, forward to a cell, or reject. Different numbers run different modes simultaneously.

Browser softphone

Make and take calls from any tab — DTMF keypad, mute, mid-call recording. Your laptop is the phone; no desk hardware to buy.

Recording on every call

MP4 audio + full transcript persist per call. Retention scales with your plan. Play back inline on the report, or download for review.

Liquid prompt templates

Author scripts once with {{ variables }} and conditionals. Reuse across calls — per-call values get rendered server-side at run time.

Outbound jobs with idempotency

Drop a list of numbers, pick an agent, schedule. The runner places calls with idempotency keys so retries never double-dial.

Caller-id routing

Point a number at your agent, then add caller-id rules to route specific callers (VIPs, repeat customers) to different agents from the same line.

Edge by default

Built on Cloudflare Workers + Firebase. No servers to babysit. Cookies are HMAC-signed; webhooks are signature-verified.

Pricing

Pay for the calls you make

Hobby
$49/mo
120 min/mo
Popular
Pro
$200/mo
10 hrs/mo · recording
Business
$2,000/mo
100 hrs/mo · inbound + reports
See full pricing

FAQ

Questions, answered

What languages does the agent speak?+
English by default. The agent mirrors whatever language the recipient speaks — Mandarin, Spanish, French, Japanese, Korean, and 90+ others — and switches mid-call automatically. No language selector to configure.
Does it work for both inbound and outbound calls?+
Yes. Buy a number, point it at an agent, and you can both receive calls and place outbound jobs to a list of contacts. Per-number you pick one of five inbound modes: AI agent, browser softphone (you answer in your tab), copilot (you answer with AI suggestions on screen), forward to another phone, or reject.
What's copilot mode?+
You make the call, the agent doesn't speak. It listens to the live transcript, reads the objective you set, and writes one short sentence at a time on your screen for you to say out loud. The caller hears a human voice — yours — but you're never wondering what to say next. Great for sales discovery, high-trust outreach, and any conversation where full-AI feels too risky.
Do my callers know they're talking to AI?+
Depends on the mode. In full-AI mode the caller is talking to the agent and most can tell within a few turns. In copilot mode they're talking to you — the AI is silent on the wire, only feeding suggestions to your screen. In direct/forward modes there's no AI in the loop at all. You pick the mode per number, and you can swap any time.
How is my data secured?+
Calls are stored per-user in Firestore with rules that pin every read/write to the signed-in user's uid. Recordings live in Firebase Storage and auto-delete on a schedule that scales with your plan. We use third-party providers (carriers, STT, TTS, LLM) — don't send sensitive info you wouldn't trust with them.
Can I bring my own phone number?+
Today, numbers are provisioned through us (US local + toll-free). BYO carrier is on the roadmap — the architecture already supports multiple number providers; we just haven't shipped the third-party trunk UI yet.
What does outbound A2P SMS look like?+
US numbers require 10DLC (local) or Toll-Free Verification before carriers accept outbound texts. We provision the number and link the webhook; you complete the verification through our partner provider once and outbound flows after.
Can the agent transfer to a real human mid-call?+
Yes. Set an admin-controlled transfer number on the agent, and the LLM gets a transfer_call tool. The destination is locked — the model can choose WHEN to escalate but not WHERE. Also works for warm-transferring outbound calls.
Is there a free trial?+
A 14-day trial on every plan. No credit card to start. Cancel any time from the Account page; numbers are released and recordings deleted within the retention window.

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