So much for the claims of fast customer service. On free trial, emailed support directly, after 2 days, crickets. I've searched all my Gmail, including trash folder. Nothing. Disappointed.
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UPDATE1. Warning. I have only about 2000 products, maybe closer to 2500, and Send Owl has a warning built into their software saying they can't load my "large" number of products into their dashboard so I tragically can't use the dashboard. It says I have to use the pull down dot dot dot apps function within Shopify alone. Big bummer. Not going well so far. I wonder if I will be able to even do Drips without dashboard access? DRIPs r only reason I am interested in this app.
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UPDATE2. So working on single product level within Shopify, good news is that selecting Send Owl app in Shopify on the single product level does successfully launch you back into Send Owl app dashboard with that singular product identified and selected. Good news also that Drip is available along this path. Bad news is that the Drip file DELIVER is absolutely not working. It is basically inert. Says no matches found. No indication whatsoever as to how to attach a digital file and it really does appear to be non functional. I work strictly over my smartphone in Android environment as I despise Windows. I have already checked "request desktop site" in Android Chrome browser but no dice. Am heading to local shop to get on a desktop to do the exact same thing on Windows to see if it works there and thus see if Send Owl just isn't up to snuff in Android environment.
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UPDATE3: So here I am now, sitting in front of a desktop computer running Windoze. And the same "inert" Drip DELIVER functionality is present, so I conclude it's definitely not an Android operating problem, seeing that the same problem exists in Windoze. And then I find this bombshell under DRIP online help instructions at SendOwl:

Attention Shopify users!

While SendOwl links to your Shopify account to help you sell and securely deliver digital products, bundles, software and much more, we are not able to integrate our ‘File Access’ or ‘Drip’ subscriptions with the Shopify checkout process.

>>>Egads. Sigh. So disappointing. This is obviously a very high quality product as long as your parameters fit within THEIR parameters. And their parameters are fairly wide, better than any other Shopify app I know of with regards to digital downloads. But unfortunately, if you want to do DRIPS, it's just not going to work within the Shopify environment. Which shocks me, seeing as it seems like this is designed to be a Shopify-friendly app. I'm keeping the 1-star rating because, for me, without the DRIP functionality available as a Shopify-centric merchant, this app is not valuable to me. It is doubtless valuable to others but make sure it will do for you what you expect/want it do as it's not a given, obviously. That's what free trials are for, clearly. And reviews.

Here's the link where you'll find the warning that DRIP doesn't work with Shopify products:

https://help.sendowl.com/help/drip-subscriptions

PS Basically, Shopify's Digital Downloads is offering to me for FREE what SendOwl wants to charge astronomical monthly sums. We've been using Digital Downloads for 2+ years and it works flawlessly for simple 1-time digital downloads associated with single product purchases. Don't see the need for SENDOWL with this limitation that they bury deeply in their DRIP help files.
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UPDATE4. Looked at Fetch, have message into them as to whether they can do anything similar to DRIP on Shopify. Waiting to hear back from them but see no evidence on their website that they have a DRIP-like function. However, a combination of CHARGERABBIT and SKYPILOT (both from the same developer, they're designed to be companion apps) looks VERY promising to accomplish DRIP-like functionality ON SHOPIFY. Will update as soon as I know more. I've got messages into them as well. And no, I don't work for CHARGERABBIT/SKYPILOT, I'm just a Shopify merchant looking for solutions for Shopify merchants and sharing what I find. I do tons of reviews here on Shopify, always evenhanded and straightforward and FAIR.
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UPDATE5. So after writing this review Send Owl finally contacts me. So it is clear that Send Owl does NOT use the Shopify checkout process which is why its DRIP function doesn't work on Shopify. This also means that Send Owl does NOT update the Shopify order register when an order is placed. Instead, Send Owl only updates the Send Owl order register since this is where the order actually transacts. This is a HUGE problem if u r running an affiliate program like LeadDyno that MUST have all of ur orders registering in Shopify in order for ur affiliates to get correctly and fully paid for their sales. Or any other app dependent on the Shopify order register actually registering your orders as a Shopify merchant. Charge Rabbit, unlike Send Owl, has already indicated to me that they DO register their orders under the Shopify orders register so I am going to try Charge Rabbit. Send Owl says they may or may not improve Send Owl to register orders in the Shopify orders register. I can't wait for this possible but not promised indefinite date improvement. It's a deal killer for me. Easy call. 1-star still.
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UPDATE6:

George and company in Feb of 2017 did eventually make the DRIP process register in the Shopify order register. That should, in theory, cause apps like LeadDyno to pick up those DRIP transactions to pay affiliates. And help any app like LeadDyno that relies on the Shopify order register to work properly.

I looked at it briefly at the end of my free trial and it looked good on paper. But I've yet to try it out in the real word yet cuz I'm not ready to start the paid sub yet.

I may eventually upgrade to 5 stars, but for now, raised from 1 star to 4 stars.

SendOwl is awesome! Meets all our needs for delivering pdf files to customers.

Great app and customer service was very helpful. Highly recommend this app!

We love this app. Our store sells Adobe Photoshop and Illustrator files, and SendOwl is able to handle them with no problem. I would definitely recommend SendOwl for all of your digital products.

Great app, easy to use. Excellent and responsive customer service!

Excellent app, especially the pdf stamping feature!

Brilliant app, was the main reason I moved from Bigcommerce to Shopify. The stamping and securing of PDF's and speed and ease of delivery are fantastic features.

I use SendOwl to deliver tutorials in PDF format, and it works perfectly. It was easy to set up, and I've been really happy with the automation.

We sell film downloads and SendOwl has cut our customer service down to next to nothing. Best app we've used for digital delivery by far. Customer support has been amazing. Paul replies really fast and is always helpful.

We have been using SendOwl for 4 months now and we are impressed at how well it works. Integration with Shopify was easy and intuitive and we have now made our 400 products available as PDF downloads which our customers certainly appreciate. Paul and George (SendOwl support) were responsive with questions and even set up a custom plan as we do not use a lot of storage but have a lot of SKUs.
I love to ability to send stamped PDF's to customers as well as issue free orders when needed.
--Marshall
Montessori123.com