Communications

Twilio provides cloud APIs for sending SMS, voice calls, email, RCS and other messages, and for adding conversational AI to applications. Businesses use these APIs to build customer communication experiences across multiple channels.

Slack is a messaging and collaboration platform that enables teams to communicate via channels, direct messages, and video huddles, and to integrate with other software tools. It is used by businesses and other organizations for internal and external communication and workflow automation.

Mailgun provides an email delivery and validation API that lets developers send, receive, track, and verify transactional emails. It is used by businesses to integrate email functionality into their applications.

Zoom provides video meetings, chat, phone, webinars, and other collaboration services that organizations and individuals use to communicate online.

Google Workspace provides a suite of cloud‑based productivity and collaboration applications such as Gmail, Calendar, Drive, Meet, Chat, Docs, Sheets, and Slides. Organizations use it for email, file storage, video meetings, and document creation.

Postmark offers an email delivery platform that allows developers to send transactional and marketing emails through an API or SMTP. Companies use it to deliver messages to recipients' inboxes.

ElevenLabs offers speech synthesis, voice cloning, and conversational voice agent services through APIs and platforms for developers, enterprises, and content creators.

Deepgram provides APIs for speech-to-text, text-to-speech, and voice agents. These APIs are used by developers, product teams, platforms, and enterprises to add voice capabilities to their applications.

Mailchimp offers an email and SMS marketing platform that enables businesses to create, send, and automate campaigns, manage contacts, and track performance through analytics and integrations. The service is used by retailers, small businesses, non‑profits, and professional service firms.

Bird provides a communications API that enables developers to send and receive email, SMS, WhatsApp, and voice messages through a single interface on a network that carries a large share of commercial messages.

Pusher offers hosted real‑time APIs that let developers add features such as push notifications, in‑app chat, live dashboards, and location tracking to mobile and web applications.

Svix provides a webhook delivery service that allows developers to send and receive webhooks with retries, signature verification, and a management dashboard. The service is used by startups and large enterprises to handle webhook traffic at scale.

Vonage provides voice, messaging, video, and data communication services through unified communications, contact center solutions, and communication APIs for businesses and developers.

Telesign offers phone number, SMS, voice, and identity verification APIs that businesses use to authenticate users and communicate with customers worldwide.

Cartesia provides streaming text-to-speech and speech-to-text APIs that generate natural voice output and transcriptions in multiple languages, enabling developers to build voice agents and interactive applications.

Sinch provides messaging, voice, email, video, and verification APIs that businesses and developers use to add communication capabilities to their applications.

Daily provides real-time voice, video, and AI infrastructure and SDKs for developers, running on a global WebRTC network. It also maintains the open-source Pipecat framework for building conversational AI agents.

AssemblyAI offers speech-to-text, speech understanding, and voice agent APIs that developers can integrate into applications to transcribe audio and extract insights. The services support real-time and pre-recorded audio for building voice assistants and other voice-enabled products.

Infobip provides a cloud communications platform with APIs for SMS, email, voice, and chat apps, enabling businesses to send messages, authenticate users, and build conversational experiences across multiple channels.

Resend offers an email sending service and API that allows developers to programmatically send transactional and marketing emails.

Loops offers email marketing software that enables SaaS teams to create and send marketing, lifecycle, and transactional emails from a single platform.

Knock is a customer engagement service that lets developers and product teams send email, SMS, push, chat, and in‑app messages through APIs, SDKs, and a dashboard. It also offers data ingestion, segmentation, and workflow capabilities for building messaging experiences.

Discord offers voice, video, and text chat that lets gamers and other users communicate and build online communities. It is used by individuals and groups to talk, play games, and share media.

Appcues offers a platform that enables go-to-market teams to build and deliver personalized in-app, email, and mobile experiences to their users. It is used by product, marketing, and customer success teams to improve onboarding, adoption, and retention.