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Fix: Stripe 'This phone number cannot be used' for AI Agents

Solve Stripe phone verification errors for AI agents. Learn about carrier lookup, VoIP blocking, and how to use real SIM numbers that pass verification.

If you're building AI agents that need Stripe accounts, you've hit this error: "This phone number cannot be used for verification." Stripe blocks VoIP numbers at the carrier lookup level. Here's how it works and how to fix it.

Why Stripe Blocks Your Number

When you submit a phone number, Stripe queries carrier databases before sending any SMS:

  1. LERG (Local Exchange Routing Guide) — Maps every North American number to its carrier and line type
  2. NPAC (Number Portability Administration Center) — Tracks numbers ported between carriers
  3. HLR (Home Location Register) — Real-time check of mobile network registration

If the lookup returns line_type: "voip" — instant rejection. The SMS is never sent.

Who Gets Blocked

ProviderLERG CarrierLine TypeStripe Result
TwilioTwilio Incvoip❌ Blocked
Google VoiceGooglevoip❌ Blocked
VonageVonagevoip❌ Blocked
TextNowTextNowvoip❌ Blocked
AgentSIMT-Mobile USAmobile✅ Passes

A Stripe security engineer confirmed the logic on Hacker News:

"We reject VoIP phone numbers due to proven fraud activity. VoIP numbers can be obtained with no identity verification, recycled instantly after use, and are disproportionately associated with account takeover attempts."

The Fix: Real SIM Numbers via AgentSIM

AgentSIM provisions actual SIM-backed numbers on carrier networks. They pass LERG, NPAC, and HLR checks because they ARE real mobile numbers.

Install

pip install agentsim-sdk playwright
playwright install chromium

Stripe Account Verification

import agentsim
from playwright.async_api import async_playwright
import asyncio
 
agentsim.configure(api_key="asm_live_xxx")
 
async def verify_stripe_account():
    async with async_playwright() as p:
        browser = await p.chromium.launch()
        page = await browser.new_page()
        await page.goto("https://dashboard.stripe.com/register")
 
        # Fill registration fields...
 
        # Phone verification step
        async with agentsim.provision(
            agent_id="stripe-signup",
            country="US"
        ) as num:
            print(f"Using: {num.number}")  # Real T-Mobile number
 
            await page.fill('[name="phone"]', num.number)
            await page.click('button:has-text("Send code")')
 
            # Wait for Stripe's SMS on real SIM
            otp = await num.wait_for_otp(timeout=120)
            print(f"Stripe code: {otp.otp_code}")
 
            await page.fill('[name="code"]', otp.otp_code)
            await page.click('button:has-text("Verify")')
        # Number auto-released
 
        print("Stripe account verified!")
        await browser.close()
 
asyncio.run(verify_stripe_account())

Synchronous Version

import agentsim
 
agentsim.configure(api_key="asm_live_xxx")
 
with agentsim.provision_sync(agent_id="stripe-bot") as num:
    print(f"Phone: {num.number}")
    # Enter number on Stripe...
    otp = num.wait_for_otp_sync(timeout=60)
    print(f"Code: {otp.otp_code}")
    # Enter code on Stripe...
# Auto-released

With MCP (Claude Code / Cursor / Windsurf)

{
  "mcpServers": {
    "agentsim": {
      "url": "https://mcp.agentsim.dev/mcp",
      "headers": {
        "Authorization": "Bearer asm_live_xxx"
      }
    }
  }
}

Your AI coding agent calls provision_number → enters it on Stripe → calls wait_for_otp → enters the code. No SDK needed.

Carrier Lookup Comparison

// AgentSIM number — passes Stripe:
{
  "number": "+14155552671",
  "carrier": "T-Mobile USA",
  "line_type": "mobile",
  "hlr_status": "active"
}
 
// Twilio number — blocked by Stripe:
{
  "number": "+19876543210",
  "carrier": "Twilio Inc",
  "line_type": "voip",
  "hlr_status": "unreachable"
}

Success Rates

ProviderStripe Success RateCost
Twilio0%$1.15/number
Google Voice0%Free (ToS risk)
AgentSIM100%$0.99/session

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