The winning streak at Twilio (NYSE:TWLO) continues. Shares of the communications software specialist have moved higher for six straight trading days, soaring 15.1% in the process. 

The biggest bump in the rally happened yesterday, after JMP Securities analyst Patrick Walravens put out a bullish note on the stock. Twilio shares have been clawing their way back since last month's stumble, when it hosed down its guidance following a mixed quarterly report. Walravens thinks last month's concerns are overblown, after some checks show that Twilio's core business keeps growing and may even be accelerating. That analyst thinks Twilio stock could double by 2019.

JMP Securities' Walravens feels that Twilio stock can deliver healthy long-term appreciation off of current levels. Doubling in two years is a pretty brazen bet, but it would still find the stock trading for less than its post-IPO peak. 

The exterior of a Signal conference.

Image source: Twilio.

Double bubble

Friday will mark the first anniversary of Twilio's IPO. The stock has nearly doubled since going public at $15 on June 23, but it's been a wild rookie year. It initially more than quadrupled a few weeks into its publicly traded tenure, but it has since shed more than half of its peak value.

Twilio provides developers with in-app communications functions, and it's clearly still growing. Analysts see revenue growth decelerating since this first quarter's 47% top-line spurt, eyeing just 34% growth during the current quarter and 25% for the third quarter.

Twilio's base of users is growing quickly, but it's still at the mercy of some of its largest accounts, including Uber, WhatsApp, and Airbnb. Uber accounted for 17% of Twilio's revenue during the fourth quarter, but that's now slipping to 12%, and Uber's testing of some non-Twilio partners weighed on the software provider's outlook. Reports indicate that Airbnb is also kicking the tires of rival providers.

Slowing growth may be problematic to upstarts with limited profitability, but Twilio continues to serve the in-app communications needs of some of the most popular mobile platforms. We'll have to wait until 2019 at the earliest for positive earnings, but if Twilio is able to stabilize its revenue growth -- and possibly even accelerate that pace -- it wouldn't be a surprise to see Twilio shares revisit last year's highs, doubling in the process as it proves Walravens right.