Infobip

Infobip is a global CPaaS with particularly strong coverage in EMEA and APAC — competitive pricing against Twilio for SMS and WhatsApp in those regions. WhatsApp Business API through Infobip is a popular alternative to Twilio for teams targeting international markets. For agents: SMS API for OTP and notifications, WhatsApp Business API for rich media messages, voice API for automated calls, and 2FA (two-factor authentication) API for phone verification flows. Official SDKs for all major languages. Confidence is docs-derived.

REST API at {base_url}.api.infobip.com (account-specific subdomain). SMS: POST /sms/2/text/advanced ({messages: [{from, destinations: [{to}], text}]}). 2FA: POST /2fa/2/applications creates app; POST /2fa/2/applications/{appId}/messages creates message template; POST /2fa/2/pin sends OTP PIN. WhatsApp: POST /whatsapp/1/message/template sends template message ({messages: [{from, to, content: {templateName, templateData, language}}]}). POST /whatsapp/1/message/text sends free-form text (within 24h session window). Voice: POST /voice/1/tts/single sends TTS voice call. Email: POST /email/3/send (multipart: from, to, subject, text, html). Push: POST /push/1/message sends push notification. Webhooks: configure delivery reports for async status.

API key auth: Authorization: App {api_key} header. Keys from Infobip Portal → API Keys. Account-specific base URL (your-account.api.infobip.com). HTTPS enforced. No OAuth2 for API access. WhatsApp: approved message templates required for outbound messages outside 24h session window. Sender IDs: pre-register numbers or alphanumeric sender IDs. Webhook auth: Infobip supports HMAC signature verification for delivery reports.

Standard HTTP status codes with JSON error bodies ({requestError: {serviceException: {messageId, text, variables}}}). 400 for invalid phone number format. WhatsApp template not approved: error on send — pre-approve templates in Infobip portal. Delivery reports: async via webhook or polling GET /sms/1/reports. 2FA flow: send OTP → user enters code → POST /2fa/2/pin/{pinId}/verify ({pin}) → {verified: true/false}. Infobip uptime at infobip.com/status. Rate limiting: per-account (varies by plan). Number format: E.164 format required ({country_code}{number} without +).

infobip.com/docs covers SMS API, WhatsApp Business API, 2FA API, Voice API, Email API, and SDK guides. Getting started: create Infobip account (free trial credits), get API key and base URL — first SMS in under 10 minutes. Official SDKs: infobip-api-python-sdk, infobip-api-java-sdk, infobip-api-php-sdk, infobip-api-go-sdk, infobip-api-csharp-sdk, infobip-api-node-js-sdk, infobip-api-ruby-sdk. Community via Infobip developer documentation and support. Good documentation for a full-featured CPaaS platform.