Dialogflow - Conversational UX Platform. (ex API.ai)

Handwrytten - Handwritten notes straight from your device. Huge selection of cards or design your own. Handwriting service integrates with 1000's of apps.

Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.

Felt for iPhone - Handwritten cards for the modern world

Botkit - Botkit is an open source developer tool for building chat bots, apps and custom integrations for major messaging platforms.

Inkpact - Send genuine handwritten messages in just a few clicks