Customize buttons, surveys, and chat windows to support your brand. Thanks to our investments in technology and channel, we have more products to sell, more partners to sell with, more references to support our selling efforts and in industry that is moving into mainstream adoption and ready to make purchase decisions. Oh great. Thanks for taking my questions, and a great finish to the year. So, they continue to be a great selling tool to just make it easier to complete a transaction, get the customer to experience the returns on the platform quickly and then work with them down the road on how to adjust it in the scope of our platform to the services that they need. And more importantly than just closing them, we’re finding that they translate into bigger engagements down the road. We are well over 100 now in the pipeline, and we’re closing them.
And we executed well on the full-year 2018 plan, exceeding even our own expectations. Every simple move took a noticeable fraction of a second (like 0.3-0.5 second), crafting and such was very slow as well. Focusing first on the specificities and timing of our investment profile; and second, on its return and contribution to our ramping growth rate and operating leverage during 2019, and into 2020. First, with respect to investment, our plan is to increase sales capacity by 90% in 2019. In order to maximize in-year productivity, hiring will be heavily weighted toward the first and second quarters, and is anticipated to be allocated as follows. Combined, the demand in our pipeline is outpacing our sales capacity, which presented great opportunity as seen on Page 13 of our supplemental earnings deck. Freenode IRC network often has over 1,000 people connected to it, and is a great alternative to the Slack channels. But none of these servers would give you control over computing you do on it, unless it’s your server (one whose software load you control, regardless of whether the machine is your property).
Over that same period, the number of enterprise pipeline opportunities is up approximately 80%, driven by strong demand for our accelerated pilot program. In your commentary you gave the revenue renewal rate was about 90% and enterprise was in the mid-’90s. Given the immediate and consistent hiring quickly and heavy volume of first-quarter and second-quarter customer summits, we anticipate modest losses in the first half of 2019, with a double-digit margin in the second half, as hiring the base, marketing spend is low and our go-to-market investments begin to drive higher revenue. On the back of that momentum, we then expect to generate at least 20% growth for the full year of 2020. From the 2019 profit perspective, our hiring activity will be heavily front-end loaded for both sales capacity and the continued buildout of our global product organization. We expect the vast majority of our hiring in both areas to be complete by the end of the second quarter and anticipate minimal head count growth in the second half. From an in-year payback standpoint, we expect our new sales reps and customer event activities to produce an initial revenue contribution by the third quarter of 2019, a more meaningful contribution in the fourth quarter and then full contribution by early 2020. More specifically, we’re issuing revenue guidance for 2019, in a range of 285 million to 293 million or 14% to 17% year-over-year growth.
We expect continued mid-teens growth in the first half of 2019 as we build our sales capacity and drive more initial opportunities through low price accelerator packs. As we talked about on prior calls, we began the year, I guess, we launched our accelerator pilots in late first quarter, hit around 25 opportunities. And, I guess, any sort of commentary on the proof of concept trends entering 2019 versus 2018 would be helpful. First, our disciplined test-and-learn approach to investing in technology and demand generation in 2018 worked. In 2018, we focused on building market awareness and creating a scalable demand generation engine. We have to fully scale out our technology, demand generation and sales team. Compared to industry benchmark, our average sales rep is currently handling two to three times the number of opportunities that would be ideal. Brandon has a wide array of sales experience which he details in his favorite sales success story, one that centers on a letter-writing campaign to Delta Airlines. It should be a secret to no one that I am no fan of the news industry and that you should not be consooming anything it produces for an audience that is not your local community.