Today (Nov 13, 2020) I'm releasing the v1.0 of this post, expect it to evolve and change over time.
Running a business is no easy task, whether you're building something on the evenings and weekends or grinding 80 hour weeks to scale your business - using the right tools is a very important element to give you the best chance at success. The tools below are what I use on stores doing anywhere from $500,000 - $100,000,000+/yr in revenue. If you're doing less than the above range these tools can still be helpful and many of them will have plans that scale with the size and needs of your store as you grow but if you're struggling to hit ~50k consistently in monthly revenue, I'd suggest limiting any external expenses to maximize the profitability of your store.
I've used both, they both are great tools and integrate with everything else on this list. I use Privy on more sites currently as their pricing is a little more affordable and it's easy to bounce between monthly rates if you have huge surges of traffic. Nothing negative to say about JustUno, if you're on the upper end of the above revenue spectrum this is a no-brainer. They are both great tools, at their core same functionality but JustUno does have a few features that edge it out on top but it does come at a cost.
Postscript is the leader in SMS, do other platforms have identical features? Sure. Does Postscript print money for me? Yes. The above link comes with an extended trial which allows you to send free SMS campaigns, during the first two weeks of the trial I've made ~$100,000 for a single brand just by sending emails with a call to action of signing up for the VIP text club and giving them a 20% discount code for completing signup. This tool is extremely powerful both for list building, sending campaigns and using automations to convert more abandoned carts.
Klaviyo is the golden standard of email service providers in the commerce world. I'd recommend this to everybody selling online regardless of annual revenue, their plans scale based on how many emails you collect and how many emails you send, but this is a tool that prints money. For all of my business Klaviyo (email) makes up 20-30% of the stores total revenue, so if your business is doing a million dollars without any emphasis on email that could be an extra $250k/yr you're missing out on! Klaviyo has all the basic features of sending automated flows like a welcome or abandon cart but also things like back-in-stock notifications so you can email people when you restock items that were sold out - demand planning is something nobody enjoys doing but if you have hundreds of people asking for an item that's been sold out why wouldn't you make more!
So you're spending money on ads but do you know where your revenue is coming from? This platform breaks out your revenue and shows the origin source but also the path to conversion, how many customers are clicking on a Facebook ad, then signing up for emails, come back to your site from a Google PPC ad and then end up converting from an affiliate placement? This single transaction could be showing a conversion and $ across all of these channels but the revenue was only realized once. Understand the part each of your channels plays in conversion, I've used this tool to optimize some of my campaigns to shift from a CPC (cost per conversion) to a CPM (cost per thousand views) or CPC (cost per click) so you make your ad dollars stretch further. The best part is you don't need a developer or a data scientist. It can also do much more than what I listed above (which is what I use it for) this platform can also show you user journey, funnel optimization, event tracking and insights into your store. This tool is very powerful and punches well above it's weight, I've seen tools that have half of the above features charging $50k/year where this platform costs me $650/mo for up-to a million monthly visitors and starts as low as $350/mo, all with no contracts which is amazing.
Have you ever had a carrier (USPS, Fedex, UPS, Purolator, etc) lose an item or a customer say the item wasn't delivered? For orders under $100 customers can insure their order for less than $1 to cover their package from anything going wrong between it leaving your hands and it arriving at the front door of the customer who ordered it. If something goes wrong and the customer paid for Route insurance, Route will either refund the customer (but you keep money from the initial transaction) or Route will place another order on your site to ship a replacement item - which means you get paid twice! This platform is super easy to install and gives you a little bit of assurance that nothing will go wrong after you complete a sale, and best of all it doesn't cost you anything!