Quite a few depending on what level of control/functionality you are looking for.
Some are more developer/write your own code focussed, other more graphically focused.
In alphabetical order and not exhaustive.
API.AI (now Google)
Chatfuel (YC)
Converse.AI (disclaimer, $currentstartup)
Flowxo
Gupshup.io
IBM Watson Engagement Advisor/Watson
Meya.ai
Microsoft Bot builder
Motion.ai
Wit.ai (Facebook)
AWS also has a suite of tools that between them you could use, check out Lex, Polly & Steps
All of these do one or more of the following:
NLP
User management
Messaging Platform Integrations
Conversation State & Context Management
Workflow
Human Escalation
Backend integrations (Helpdesk, CRM etc)
Analytics
Pick your poison based on what you need :)
Some are more developer/write your own code focussed, other more graphically focused.
In alphabetical order and not exhaustive.
API.AI (now Google) Chatfuel (YC) Converse.AI (disclaimer, $currentstartup) Flowxo Gupshup.io IBM Watson Engagement Advisor/Watson Meya.ai Microsoft Bot builder Motion.ai Wit.ai (Facebook)
AWS also has a suite of tools that between them you could use, check out Lex, Polly & Steps
All of these do one or more of the following:
NLP User management Messaging Platform Integrations Conversation State & Context Management Workflow Human Escalation Backend integrations (Helpdesk, CRM etc) Analytics
Pick your poison based on what you need :)