API DIRECTORY · COMMUNICATE AND COLLABORATE

Communication: Messaging, Email, SMS & Voice

58 companies and tools in this category. Each listing links to the provider’s own website. Search the full directory

100msHosted API
Live video and audio SDKs
Open documentation Pricing Status Details
Official source checked · checked 2026-10-27
AblyHosted API
Realtime pub/sub messaging
Set up API access Docs Pricing — No pricing page listedStatus Details
Official source checked · checked 2026-10-27
AgoraAccess needs review
Listed in the supplied document; current public API availability is not confirmed
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · API access unverified · checked 2026-10-23Current public API access is unconfirmed; check the provider’s access options.
AircallHosted API
Cloud phone system for teams
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-27
Amazon SESHosted API
Email sending
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23
BandwidthHosted API
Voice, messaging and 911 APIs
Open documentation Pricing Status Details
Official source checked · checked 2026-10-27
Bird (MessageBird)Hosted API
Omnichannel messaging: SMS, WhatsApp and email
Get an API key Docs Pricing Status Details
Official source checked · checked 2026-10-27
BrevoHosted APIFree option
Customer messaging
Get an API key Docs Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
Cal.comHosted API
Scheduling platform
Open documentation Pricing Status Details
Official source checked · checked 2026-10-23
CalendlyHosted API
Scheduling integrations
Open documentation Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
CourierHosted API
Send transactional notifications and customer message journeys across email, SMS, push and in-app inboxes.
Open documentation Pricing Status Details
Official documentation checked · checked 2026-10-25Requires an API key. Courier is a managed cloud platform; the official guide states that self-hosting is not offered.
DailyHosted API
Real-time video/audio
Open documentation Pricing Status Details
Official source checked · checked 2026-10-23
DialpadHosted API
Business phone and contact center
Open documentation Pricing Status Details
Official source checked · checked 2026-10-27
DiscordHosted API
Community and bot integrations
Get an API key Docs Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23
Facebook MessengerAccess needs review
Listed in the supplied document; current public API availability is not confirmed
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · API access unverified · checked 2026-10-23Current public API access is unconfirmed; check the provider’s access options.
Firebase Cloud MessagingHosted API
Push notifications
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23
FreshworksHosted API
Business workflow integrations
Open documentation Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
Gmail APIHosted API
Mail
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23
Google CalendarHosted API
Meetings, scheduling
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23
Google MeetHosted API
Meetings, scheduling
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23
GotifySelf-hostedOpen source · MIT
A simple server for sending and receiving messages in real-time per WebSocket. (Includes a sleek web-ui)
Open documentation Pricing — No pricing page listedStatus — No status page listedSource code Details
Official source checked · checked 2026-11-10
InfobipHosted API
Omnichannel messaging and voice
Open documentation Pricing Status Details
Official source checked · checked 2026-10-27
IntercomHosted API
Customer messaging
Open documentation Pricing Status Details
Official source checked · checked 2026-10-23
KitHosted API
Email marketing
Open documentation Pricing — No pricing page listedStatus Details
Official source checked · checked 2026-10-23
KlaviyoHosted API
Email marketing
Open documentation Pricing Status Details
Official source checked · checked 2026-10-23
KnockHosted API
Trigger multi-channel notification workflows and build in-app notification feeds, user preferences and delivery tracking.
Open documentation Pricing Status Details
Official documentation checked · checked 2026-10-25The REST API uses an API key as an Authorization bearer token.
listmonkSelf-hostedOpen source · AGPL-3.0
High performance, self-hosted, newsletter and mailing list manager with a modern dashboard. Single binary app.
Open documentation Pricing — No pricing page listedStatus — No status page listedSource code Details
Official source checked · checked 2026-11-10
LiveKitHosted API
Real-time video/audio
Open documentation Pricing — No pricing page listedStatus Details
Official source checked · checked 2026-10-23
LoopsHosted API
Manage contacts, send transactional email and trigger customer email workflows from product events.
Set up API access Docs Pricing Status Details
Official documentation checked · checked 2026-10-25API requests use a bearer API key.
MailchimpHosted API
Email marketing
Open documentation Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
MailerSendHosted API
Transactional email API with templates, delivery tracking and an official Node.js SDK.
Set up API access Pricing — No pricing page listedStatus — No status page listedDetails
Official documentation checked · checked 2026-11-08
MailgunHosted APIFree option
Email delivery and validation
Open documentation Pricing — No pricing page listedStatus Details
Official source checked · checked 2026-10-23
MailjetHosted API
Send transactional emails and manage email resources through the Mailjet API.
Set up API access Pricing — No pricing page listedStatus — No status page listedDetails
Official documentation checked · checked 2026-11-08
MailSlurpHosted API
Create inboxes, send and receive email, and test email or SMS workflows through an API.
Set up API access Pricing — No pricing page listedStatus — No status page listedDetails
Official documentation checked · checked 2026-11-08
MailtrapHosted API
Email sending and sandbox testing APIs for application notifications and email development.
Set up API access Pricing — No pricing page listedStatus — No status page listedDetails
Official documentation checked · checked 2026-11-08
Microsoft GraphHosted API
Microsoft Graph API for Microsoft 365 productivity integrations, including mail, calendars and files.
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23Required OAuth authorization, scopes and permissions depend on the operation. Use the appropriate Microsoft account or organizational permissions for the resources you need.
NovuHosted API
Build notification workflows across in-app inboxes, email, SMS, push and chat with delivery and preference controls.
Open documentation Pricing Status — No status page listedDetails
Official documentation checked · checked 2026-10-25Server requests use an environment secret API key with the ApiKey authorization prefix. Open-source and managed options are documented.
ntfySelf-hosted
Send push notifications to your phone or desktop using PUT/POST
Open documentation Pricing — No pricing page listedStatus — No status page listedSource code Details
Official source checked · checked 2026-11-10The repository is dual licensed: Apache-2.0 and GPL-2.0.
NylasHosted API
Build email, calendar, contacts and scheduling features against connected customer accounts.
Open documentation Pricing — No pricing page listedStatus Details
Official documentation checked · checked 2026-10-25Nylas API credentials and end-user authorization are required.
OneSignalHosted API
Push notifications
Open documentation Pricing Status Details
Official source checked · checked 2026-10-23
PlivoHosted API
Voice and messaging
Open documentation Pricing Status Details
Official source checked · checked 2026-10-23
PostmarkHosted API
Transactional email
Get an API key Docs Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
PusherHosted API
Realtime messaging and push notifications
Open documentation Pricing — No pricing page listedStatus Details
Official source checked · checked 2026-10-27
ResendHosted APIFree option
Developer email delivery
Get an API key Docs Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
RingCentralHosted API
Business phone, SMS and meetings
Open documentation Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-27
SendbirdHosted API
In-app chat, calls and notifications
Open documentation Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-27
SendGridHosted APIFree option
Transactional and marketing email
Get an API key Docs Pricing — No pricing page listedStatus Details
Official source checked · checked 2026-10-23
SinchHosted API
Communication services
Open documentation Pricing — No pricing page listedStatus Details
Official source checked · checked 2026-10-23
SlackHosted API
Team communication integrations
Get an API key Docs Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
StreamHosted API
Chat, video and activity feed APIs
Set up API access Docs Pricing Status Details
Official source checked · checked 2026-10-27
TelegramHosted API
Bot messaging integrations
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23
TelnyxHosted API
Telephony and messaging
Open documentation Pricing Status Details
Official source checked · checked 2026-10-23
TwilioHosted APIFree option
Messaging and voice integrations
Set up API access Docs Pricing Status Details
Official source checked · checked 2026-10-23
VonageHosted API
Voice, video and messaging
Open documentation Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
WebexHosted API
Meetings and messaging
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official documentation checked · checked 2026-10-23
WhatsApp Business PlatformAccess needs review
Listed in the supplied document; current public API availability is not confirmed
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · API access unverified · checked 2026-10-23Current public API access is unconfirmed; check the provider’s access options.
ZendeskHosted API
Customer service workflows
Open documentation Pricing Status — No status page listedDetails
Official source checked · checked 2026-10-23
ZoomHosted API
Meetings and collaboration
Open documentation Pricing — No pricing page listedStatus — No status page listedDetails
Official source checked · checked 2026-10-23