Sites and apps similar to Authkey - SMS & WhatsApp API include UniStack. It's paid, but Wazo is free. Other options are Telnyx, Twilio, Smarter Contact and Lead Sherpa. There's no shortage of Email Marketing Services like Authkey - SMS & WhatsApp API, with more than 50 alternatives for Android, iPhone, Windows, Mac and iPad.
Started as a reimplementation of the open source Plivo Framework (unmaintained as of 2015), Eqivo simplifies the integration between web applications and voice-enabled endpoints, such as traditional phone lines (PSTN), VoIP phones, webRTC clients etc.
Instasent is one of the largest and the most secure platforms in the market, in-house developed for sending bulk SMS world wide.
Spain
EU
Chakra Chat is an official WhatsApp Business API platform for sales, support, and marketing teams.
India
Whautomate is a WhatsApp automation and engagement platform designed to help businesses improve their customer engagement and sales.
D7 SMS allows reaching the customers via SMS over D7's own connectivity to global mobile networks. D7 provides reliable and cost-effective SMS services to businesses across all industries and aims to connect all countries and territories.
Automate WhatsApp messaging, CRM, and WhatsApp Channel posting with Make.com and Zapier integration. No Meta Business API required.
NetherlandsEU
Smart 2-Way Omnichannel Messaging Platform, for Businesses, IoT, Metaverse, and the Blockchain.
United States
A comprehensive platform for managing and consolidating customer inquiries from WhatsApp to TikTok, offering automated workflows, appointment scheduling, real-time analytics, and click-to-WhatsApp for lead generation.
Eagle Messaging offers voice messaging, text SMS service, Voicemail, IVR, chat, and more. Users can send 60 minutes of a recorded voice message. Cost-Effective, unlimited SMS service & all-inclusive price (Only $10) on a per-month subscription basis.
High quality and cheap SMS gateway with coverage of 900+ operators worldwide. ? Worldwide coverage ? Free testing ? Great pricing ? Easy HTTP(s) API
TxtSync provides a web interface and API to reliably send and receive, low cost SMS and SMS Marketing Campaigns with no hidden monthly fees.
