The service, which was launched in 2016, garnered 50 million users with some innovative features but failed to match the likes of Facebook Messenger and WhatsApp - each boasting over a billion users.
It will continue to work till March 2019 and shut down after that.
Google is shutting down smart messaging app Allo
Why Google is killing off Allo?
Though Google has not detailed why it is killing Allo, the reason appears to be a general lack of interest in the service and shifting priorities to Messages.
The Messages app has already absorbed many of Allo's features, including smart replies, GIFs, and desktop support.
"Given Messages' continued momentum, we've decided to stop supporting Allo to focus on Messages," Google said in its blog post.
Google paused work on Allo earlier this year
Earlier this year, Google paused 'investment' in Allo. Following this, not much work has been done on the service and virtually the entire team working on the project has moved to Messages, Engadget reported.
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So, you have four months to export your Allo chats
Having said that, if you have been using Allo lately, you have got some four months to export all your conversations to Google Drive.
Google has given a step-by-step guide to export chats and media history, but if you fail to do this before March 2019, all your information will be deleted for good.
And, what Google plans with Messages?
With Messages, which has some 175 million monthly users, Google plans to switch to RCS chat and replace old-school messaging with an iMessage like experience (with group chats, hi-resolution photos, read receipts).
The search giant has already partnered with over 40 carriers and device makers and will roll-out the service via Verizon for the new Pixel phones on December 6, according to The Verge.