ring.sh — Agent-Native Phone

ring.sh

Phone numbers for agents.

Provision numbers, send/receive SMS, make calls, handle webhooks. x402 auth. No Twilio account. No KYC.


# Get a phone number in one request
$ curl -X POST https://ring.prim.sh/v1/numbers \
    -H "X-402-Payment: $PAYMENT_TOKEN" \
    -d '{"country": "US", "capabilities": ["sms", "voice"]}'

# → 402 → pay → 201
{
  "id": "num_p3x7k9",
  "number": "+12125551847",
  "country": "US",
  "capabilities": ["sms", "voice"],
  "webhook": null,
  "ttl": 86400
}

# Send SMS
$ curl -X POST https://ring.prim.sh/v1/sms \
    -H "X-402-Payment: $PAYMENT_TOKEN" \
    -d '{"from": "+12125551847", "to": "+14155559999",
         "body": "Deployment complete. All systems green."}'

x402 auth + payment

SMS send + receive

Voice calls

0 signup required

MCP + REST

Part of agentstack

↓ scroll

How it works

Provision number

→

📱

Send / receive SMS

→

🪝

Webhook on inbound

→

📞

Voice (TTS / record)

Numbers are ephemeral by default (24h). Extend or make permanent. Release when done.

What agents use it for

2FA verification

Agent signs up for a service that requires phone verification. Provision a number, receive the SMS code, verify, release the number. Under a minute.

SMS notifications

Text a human when something matters. Server down, trade executed, build failed. The one channel humans actually check immediately.

Conversational SMS

Agent maintains an SMS conversation with a human. Inbound messages hit a webhook, agent responds via API. No app install required.

Voice calls

Agent makes a phone call with TTS. Appointment reminders, status updates, emergency alerts. Programmable voice without Twilio.

Phone trees

Inbound calls → webhook → agent decides routing. Press 1 for support, press 2 for sales. Except the "agent" routing it is an AI.

Disposable numbers

Need a phone number for 10 minutes? Pay for 10 minutes. No monthly commitment, no plan, no account. Spin up, use, tear down.

API reference

# Number management
POST   /v1/numbers                # Provision a number
GET    /v1/numbers                # List your numbers
GET    /v1/numbers/:id            # Number details
PUT    /v1/numbers/:id            # Update TTL, webhook, capabilities
DELETE /v1/numbers/:id            # Release number

# SMS
POST   /v1/sms                    # Send SMS
GET    /v1/numbers/:id/messages   # Poll for inbound SMS
GET    /v1/messages/:id           # Get message details

# Voice
POST   /v1/calls                  # Initiate outbound call
GET    /v1/calls/:id              # Call status / recording URL
POST   /v1/calls/:id/say         # TTS into active call
POST   /v1/calls/:id/hangup      # End call

# Webhooks
PUT    /v1/numbers/:id            # Set webhook for inbound SMS/calls
# Inbound SMS → POST to webhook:
# { "from", "to", "body", "timestamp" }
# Inbound call → POST to webhook:
# { "from", "to", "call_id", "action_url" }

# Available inventory
GET    /v1/available              # Search available numbers by country/area

MCP tools

# Your agent gets these tools
tools:
  provision_number:
    country: "US"
    capabilities: ["sms", "voice"]
    webhook: "https://my-agent.example/inbound"

  send_sms:
    from: "+12125551847"
    to: "+14155559999"
    body: "Your verification code is 847291"

  read_sms:
    number: "num_p3x7k9"
    since: "5m"

  make_call:
    from: "+12125551847"
    to: "+14155559999"
    tts: "Hello, this is an automated message. Your order has shipped."

  release_number:
    number: "num_p3x7k9"

Pricing

Action	Cost	Notes
Provision number	$0.03/day	US local. Intl varies.
Send SMS	$0.008	US domestic
Receive SMS	$0.005	Webhook delivery included
Outbound call	$0.015/min	US domestic
Inbound call	$0.010/min	Webhook included
TTS	$0.005/min	Multiple voices
Call recording	$0.002/min	Stored 24h default

A full 2FA flow (provision + receive SMS + release) costs under $0.04.

A phone number is an API call.

Agents don't have phones. They have HTTP clients.

Read the docs →

or just: curl https://ring.prim.sh/v1/available?country=US