How to
![Message Timestamps image](https://www.pubnub.com/cdn/3prze68gbwl1/4ne9oJW19m4obpW6TGBUEw/72769303515f46914379b1a4b3f491de/messagetimestamps.png?w=360&h=200&fit=)
Chat
Building Chat: Dealing with timestamps
Follow this how-to to understand how to deal with and format timestamps for PubNub Chat applications.
![How to telemedicine](https://www.pubnub.com/cdn/3prze68gbwl1/3kxt4nL0qg20RP3bicABzF/a7408bf07928e8b163f9a93555165c1f/How-to-Telemedicine-Image.jpg?w=360&h=200&fit=)
Chat
How to Build a Telemedicine App
Read our complete guide on making your own telemedicine app. In this guide, you’ll learn about telemedicine, HIPPA, PHI, and solutions for building.
![PubNub Portal How-To: Push Notifications for Android](https://www.pubnub.com/cdn/3prze68gbwl1/5TBAGKZp8xbaXNykvXpPoy/dab6198453019d1ccc2f6d34d382277a/Screen_Shot_2022-07-26_at_1.51.09_PM.png?w=360&h=200&fit=)
Push Notifications
Enabling Mobile Push Notifications: Android
Follow this how-to to enable PubNub's Mobile Push Gateway in the Admin Portal to send your Android users push notifications and alerts.
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PubNub portal
Enabling Persistence
Follow this how-to to enable Persistence in the Admin Portal to persist all messages as they're published.
![Telehealth Tutorial cross-platform Multiple devices showing a telemedicine chat application with conversations between doctors and patients.](https://www.pubnub.com/cdn/3prze68gbwl1/YImhMz8bJU4tjn1gXtryj/65e6df2e74858ef07bb70088dde5f026/18-new2.png?w=360&h=200&fit=)
Chat
How to Build Cross-Platform Chat Applications with PubNub
If your team is developing a cross-platform application you have a number of options to choose from but whichever approach you take, from web-only to cross-platform frameworks, PubNub can easily incorporate chat into your app.
![How-to Build Vue Chat Apps](https://www.pubnub.com/cdn/3prze68gbwl1/3unV0nzOBgNrauUqfluAd7/9b623bcba4978b74233e305899d71c9a/How-to-Build-a-Chat-App_1200x630_-1.png?w=360&h=200&fit=)
Chat
How to build a chat app using HTML, CSS, Vue, & JS
Read our complete guide to build a chat app using HTML, CSS, Vue, and JS. Read this and our other information building interactive chat apps.
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PubNub portal
Creating Keys
Follow this how-to on creating keys in the Admin Portal to connect your application to the PubNub network.
![portal files 1200x630](https://www.pubnub.com/cdn/3prze68gbwl1/5iVmmebixdKkFUcjz6ZnP9/370b7313bcb82b0ad9131a233b3c5060/Screen_Shot_2022-07-26_at_1.59.21_PM.png?w=360&h=200&fit=)
PubNub portal
Enabling Files
Follow this how-to on enabling Files in the Admin Portal to upload and share files.
![portal objects 1200x630](https://www.pubnub.com/cdn/3prze68gbwl1/5QQiQ80on4lKqvWQOBVBJ9/ba62ac7bce1f296d435f9a72e2550664/Screen_Shot_2022-07-26_at_1.59.09_PM.png?w=360&h=200&fit=)
PubNub portal
Enabling Objects
Follow this how-to on enabling Objects in the Admin Portal to to store metadata for users, channels, and memberships without the need of setting up your own database.