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Better Auth Integration

Drop-in OTP sender for Better Auth's phone number plugin.

Installation

npm install @sendlime/better-auth @sendlime/node

Basic setup

import { betterAuth } from "better-auth";
import { phoneNumber } from "better-auth/plugins";
import { sendlimeOTP } from "@sendlime/better-auth";

export const auth = betterAuth({
  plugins: [
    phoneNumber({
      sendOTP: sendlimeOTP({
        apiKey: process.env.SENDLIME_API_KEY,
      }),
    }),
  ],
});

WhatsApp OTP

Send verification codes via WhatsApp instead of SMS.

sendlimeOTP({
  apiKey: "sl_live_...",
  channel: "whatsapp",
})

Auto channel detection

Bangladesh (+880) numbers are sent via WhatsApp with automatic SMS fallback. All other country codes use SMS directly.

sendlimeOTP({
  apiKey: "sl_live_...",
  channel: "auto",
})

Custom message template

Use {{code}} as a placeholder for the OTP code.

sendlimeOTP({
  apiKey: "sl_live_...",
  messageTemplate: "SendLime: {{code}} is your verification code",
})

Options

OptionTypeDefaultDescription
apiKeystring-Your SendLime API key. Required.
channel"sms" \| "whatsapp" \| "auto""sms"Delivery channel.
brandIdstring-Sender brand ID.
messageTemplatestring"Your verification code is {{code}}"OTP message template.

Full example with client

// auth-client.ts
import { createAuthClient } from "better-auth/client";
import { phoneNumberClient } from "better-auth/client/plugins";

export const authClient = createAuthClient({
  plugins: [phoneNumberClient()],
});

// Send OTP
await authClient.phoneNumber.sendOtp({
  phoneNumber: "+8801XXXXXXXXX",
});

// Verify
await authClient.phoneNumber.verify({
  phoneNumber: "+8801XXXXXXXXX",
  code: "123456",
});