Things I wish I knew about Stripe


Striped, but not charging your credit card

So, at The Food Corridor, we’ve been using Stripe happily since we launched in June of 2016.  As a developer, I’d used Stripe before in a couple of different ways, but this has definitely been my most sustained use of the payment service.  (If you don’t know what Stripe is, it is an API that makes charging customers as easy as an API call.  More here.)

I wanted to outline some of the things I’ve learned from months of using Stripe.

  • Stripe supports pulling money directly from bank accounts, via ACH, but it really isn’t the same ACH as your bank lets you do.  This is because Stripe isn’t a bank.  The biggest thing to be aware of here is that Stripe ACH takes 7 days to arrive in your bank account.  Another issue is that you have to do verification.  They have two ways of doing verification–micro deposits and Plaid.  Plaid is instant, but only supports major banks, which was a non starter for us (updated 9/8: Plaid supports around 1000 banks now).  The code for micro deposits is straightforward, but be prepared for some customer support issues.  Stripe deposits two amounts and withdraws just one amount, which was confusing for some of our users.  It also takes a couple of days, so if your users are hot to spend money, Stripe ACH may not be a fit.  The win?  Definitely cheaper.  (And I didn’t find any other service that would support both credit card and ACH transactions that was developer friendly.)
  • Don’t forget to set up your webhooks out of the gate.  Stripe mentions this, but I glossed over it in the early days, and missed some events that were important.  (The most relevant is that ACH is asynchronous, so when an ACH transfer fails, it is reported via webhook.  If bank account verification doesn’t work, you’ll get a different kind of webhook.  Review the docs and set up webhooks for all the ACH events.)  If you don’t have time for a full featured webhook processing implementation, Zapier can just send the webhook data to your email. This can be a great stopgap solution.  Or you can use stripe_event.
  • Per support, if a webhook post fails (because your app is down, for example), they are retried once an hour for 72 hours.
  • Speaking of stopgap solutions, the Stripe Dashboard is fantastic for manual processes.  Just because you can automate everything via an API, doesn’t mean you should.  There can be some complicated edge cases with payment processing, especially around refunds, but they can easily be handled with a google doc of instructions and the Stripe Dashboard.  I have found only one use case that the API can handle that the dashboard cannot (a partial refund of an ACH transaction).
  • I have found Stripe support to be excellent, quick and knowledgeable.
  • Occasionally customer charges will be declined because of bank fraud triggers.  Expect to occasionally ask your customers to call their bank.  (I think this has happend about once every third month).
  • Disputes are a total pain, because the process is opaque and slow (expect a resolution in about two months and know you are not in possession of the payment during that time).
  • Make sure to capture the payment id anytime you charge a card or run ACH.  It will make future automation a lot easier.
  • Monthly plans are complicated, so if you can lean on Stripe for management, even if you are doing manual plan management (applying coupons, adding, or removing users from plans via the dashboard), do that.
  • The first payment you charge takes 7 days to move from stripe to your​ bank account.  This is for fraud protection.  Payments thereafter typically take 2 days (but it depends on your country and industry).

And here are some special tips if you are using Stripe Connect (their marketplace product).

  • Read the docs!
  • Remember that first payment timeline?  It applies to every one of the connected accounts.  Think about charging your own credit card as soon as you connect an account to help with customer cash flow.
  • Consider whether you want to use managed vs standalone accounts.  Managed accounts are a lot more work but allow you to have a seamless UX that you control.  Standalone accounts, which we use, are far quicker to setup.  I think this depends on the number of sellers you have in your marketplace.
  • You also want to think about whether to place the charges on the platform account or on the connected accounts.  A major factor there is who bears the Stripe fees, the platform or the sellers.  We charged on the platform account because we wanted all our data in one place.  If you are selling plans, you can’t charge on the platform and use Stripe plans.
  • If you are charging on the platform account, and are using standalone accounts (where the sellers have to set up a stripe account) your sellers won’t see charge descriptions unless you manually copy the description over.  The code looks like:

# this will let the sellers know what invoice the charge was for
transfer_id = charge.transfer
transfer = Stripe::Transfer.retrieve(transfer_id, expand: ['destination_
payment_id = transfer.destination_payment
payment = Stripe::Charge.retrieve(payment_id, {stripe_account: destinati
payment.description = description

Happy charging!

Announcing the Introduction to Amazon Machine Learning Video Course

Would you like an easy introduction to machine learning?  Without downloading any open source software, reading documentation and blog posts, and/or installing and configuring the system?

Amazon Machine Learning is a great way to explore machine learning without having to run any infrastructure.  It lets you build high performance cost effective systems to predict outcomes based on past data.

If you’re interested in learning more about Amazon Machine Learning, you can view my video course on O’Reilly Safari.  Over an hour and a half of video talking about all aspects of Amazon Machine Learning.

This course shows you how to build a model using Amazon Machine Learning (Amazon ML) and use it to make predictions. AWS expert Dan Moore covers the basic types of machine learning, how to prepare your data, and how to make your data available to the Amazon Machine Learning processes. You’ll also learn about evaluating a model for accuracy, using it both for batch and real-time predictions, and using tags to manage environments. Designed for developers and technical marketers new to machine learning and for data scientists interested in using the AWS Amazon ML platform, the course provides hands-on experience building a working predictive model using real data. Learners should obtain an AWS account (free from Amazon) and a basic understanding of AWS concepts before beginning the course.

Heroku 503 errors

One day recently I woke up to a text from our monitoring service (part of minimal heroku operations tasks) saying our application was down.

Darn it.

Here’s the recreation of my steps in troubleshooting this issue:

  • Login, see that the app is indeed down.
  • Look at newrelic.
  • Look at the logs (papertrail!).
  • Look at the deployment history.
  • Note when the issue started–curses, not when I did a deploy.
  • Open a ticket with heroku (after doing some research). (Love their support.)
  • Double check that the database is good and hasn’t hiccuped.
  • Look at the logs more.
  • Add more dynos, see if that helps.
  • Google the error message.
    •  <app-name> heroku/router: at=info method=POST path=”<url>” request_id=8a17648f-2d84-46ea-abf2-5903be894a2c fwd=”″ dyno=web.3 connect=1ms service=4ms status=503 bytes=477 protocol=https“Notice that the issue is being stated right in the log file (passenger request queue filling up).  Here are sample error messages?
    • <app-name> app/web.3: [ 2017-07-12 14:47:44.3688 65/7f652dffd700 age/Cor/Con/CheckoutSession.cpp:261 ]: [Client 3-281] Returning HTTP 503 due to: Request queue full (configured max. size: 100)
  • Find some posts about the error message.  Here and here.
  • Start researching how to increase request queue size.
  • Talk a walk to clear my head.
  • Think about what external services we call, as that seems to be what might cause the request queue to back up.
  • Read another post that says restarting passenger helped.
  • Restart all dynos.
  • Problem disappears.
  • Look at logs more closely.
  • Last dyno to be restarted was the only problematic dyno.
  • Add comment to ticket about this being the cause.
  • Heroku confirms that the issue may have been the dyno: “sometimes individual dynos will hang and cause errors with 503 responses”
  • Write note to customers about the issue explaining how access to app was affected.
  • Lower number of dynos.
  • Breath a sigh of relief.

AWS Questions: Certification

Lots of times folks in my class are interested in pursuing AWS certifications.  The classes I teach are good at preparing you to be certified, but are definitely not certification classes.  Here’s the answers I give to students interested in being certified:

To get certified, you should review the page for the cert you want.  Here’s the page for the AWS Architect – Associate certification.

When I got certified, I re-read the student guide from the class and made sure I understood everything covered in it.  I didn’t just look at what the student guide had–I went to the AWS documentation as well.  I also read some whitepapers as outlined in the exam guide (found on the certificate page linked above).  I then took the sample questions (answers not provided, but you can find them via googling, anda again, on the certificate page) and then the practice exam (which costs $20, I believe, and gives you familiarity with the test format, but can only be taken once.).  Those gave me feedback that I was on track to pass the exam.

Note that the course is more hands on than the exam and doesn’t map strictly to the exam.  However, AWS does a good job of explaining what they are looking for in the exam guide (on, you guessed it, the certificate page).

Some of my students and colleagues have also had good luck with acloudguru, but I have no personal experience with that service.  The company for which I work (but for which I do not speak) also offers a course that is designed to help folks pass certain certs, but I have no experience with the course.

Finally, it’s worth noting that all the certs I have taken have been proctored.  Depending on where you live, you may have a number of test centers available, or one (or none).  Find that out before hand!  I also found that the exams I wanted were never available next day–I had to schedule them out a few weeks in advance.  YMMV.

AWS machine learning talk

I enjoyed giving my “Intro to Amazon Machine Learning” talk at the AWS Denver Boulder meetup.   (Shout out to an old friend and colleague who came out to see it.) I didn’t get through the whole pipeline demonstration (I didn’t get a chance to do the batch prediction), but the demo gods were kind and the demo went well.

We also had a good discussion.  A few folks present had used machine learning before, so we talked about where AML made sense (hint, it’s not a fit for every problem).  Also had some good questions about AML, about performance and pricing.  One of the members shared a reinvent anecdote: the AML team looked at all the machine learning used in Amazon and graphed the use cases and solved for the most common ones.

As, usual, I also learned something. OpenRefine is a tool to help you prepare data for machine learning.  And when you change the score cut-off, you need to restart your real-time end point.

The “Intro to Amazon Machine Learning” slides are up on SlideShare, and big thanks to the Meetup organizers.

Advice for the bootstrapped developer

I participated in a panel for Boulder Startup Week, but previous to the panel, thought I’d be giving a 15 minute presentation.  I was going to talk about rules for the bootstrapped developer.  At The Food Corridor, we recently celebrated one year of having customers.  In celebration of that, here are my seven guidelines:

  1. It will take longer than you think.  For any meaningful value of “it”. expect the process to take longer than planned.  Whether that is acquiring your first customer, building your product, finding help, or anything else, plan for it to take longer than you think.  Heck, this blog post is taking longer than I thought it would.
  2. Know your runway.  It’s important to know your financial runway (both for the company and for yourself).  This is fairly easy to calculate–just find out your burn rate and your money in the bank.  If you are looking at your personal financial runway, don’t forget to allow some buffer for you to find a different job–typically you won’t be able to step from a cratered startup on Friday into a full time job on Monday.  However, more important than financial runway is emotional runway.  Talk about the stress with your spouse (if applicable), think about the other emotional difficulties you may encounter, and plan for some high highs and some low lows.
  3. Extend your runway.  Again, for the financial runway, lower your burn rate as much as you can.  This will mean cutting back on spending and savings.  Make sure the family is on board.  Then you will look to find other sources of money to feed and clothe yourself.  This may include digging into savings, borrowing against assets (HELOCs work for this), borrowing from relatives, pitch competitions (TFC won two), selling assets, taking contract work, having a spouse who earns enough for the household, and/or moonlighting.
  4. Talk to your customer. This was one of the great assets that one of my co-founders brought to the table.  She had deep domain expertise and had many connections to potential customers.  We had numerous customers give us feedback, including via interviews, a month long beta test, regular product advisory councils and surveys.  You will note that this point implies you can find your customer and communicate with them in a cost effective manner.  Find where your customer congregates online.  If you don’t find a place, make one and invite your potential customers to join.
  5. Everything is borked all the time. In a startup, you just don’t have time to do everything correctly.  It can be embarrassing, but if you are building something that solves customer pain, and you’ve found the right early adopters, the customers will stick around.  Just keep improving things.  And accept a certain amount of brokenness.
  6. Know your market. This is related to talking to your customer, as that is one fantastic way to learn about your market.  There are other ways too–market research, online reading, etc.  However, as you build your product, you will surprised by what your market wants.  For instance, we thought our market would want a better UX, but were surprised when someone said our v1 UX was “great”.
  7. Make your own rules. Know that my advice and rules above are based on my experience, with my co-founders, product and skillset, in this time.  You need to do the reading and figure out what your rules are.

DynamoDb: What’s left to manage

AWS recently announced that DynamoDb will now scale read and write capacity automatically.  While there was already a lot of database administration that DynamoDb took care of (backups, underlying infrastructure provisioning), setting the proper capacities initially, and updating them as your application changed, was a key task that fell to the user. No more.

I posted a link to the news to a discussion channel I participate in, and someone asked: “what’s left to manage?”. Drawing from that discussion, here are a few items remaining:

  • Appropriate partition keys.  Make sure they are spread uniformly.
  • Choosing the right primary key. Since you typically want to avoid table scans and can only query by primary key, making sure you pick the right one is important.  (I would also call this “data model design”.)
  • Enforcing data integrity, initially and through time.  This is a challenge with every nosql solution.
  • Creating the appropriate secondary global indices for your application.
  • Securing and controlling access to your data.

These are all still important tasks, but DynamoDb is getting easier and easier to use for high performance applications for which nosql is a good fit.  (And for which you don’t mind being tied to AWS.)

AWS Questions: SQS

More questions, this time about SQS, the simple queue service that AWS provides.

  • What was the first AWS service?
  • Are there upper limits on limits on SQS in terms of message/second?
    • FIFO Queues have a limit (300/s), but I wasn’t able to file any hard limits for standard SQS.  In the developer guide they have some examples that reach 2500 messages/second.  I found some benchmarks from 2014, which were able to get to 108k messages/second.
  • Can you create alarms based on the number of messages in a queue?
    • Yes, that is a metric that Cloudwatch tracks: “NumberOfMessagesSent”.  You can use this in combination with an auto scaling group to handle batch processes in a dynamic manner (scale out when you have more work in the queue, scale in when you have less).
  • What is the maximum visibility timeout for SQS?

Interview with a boot camp grad

Lots of folks are moving into development and technical fields these days.  I remember that happening during the dot com book, but back then folks just read one of those “Learn Java in 24 Hours” books.

Nowadays there are a profusion of boot camps that help people gain the skills they need to be a developer. I have interacted with a few of these grads and was interested in learning more about their experience. Noel Worden, one of the organizers of Boulder.rb and a blogger, agreed to an interview.

– what was your background before you were a developer?

I got my degree in fine art photography, spent 5 years working in NYC as a Digital Technician in the photo industry, then moved to Colorado and was a cabinetmaker for 3 years.

– how did you land your first job?

I found the posting on the Denver Full Stack meetup whiteboard (

– what surprised you about the software industry?

How willing everyone is to help. It’s very different in the photo world, [which is] much more competitive, it’s hard to find guidance and mentorship.

– how did you pick your boot camp?

Bloc had one of the longest curriculums I could find in an online program. I figured when push came to shove, having more experience under my belt couldn’t hurt when competing with other junior [developers] looking for that first job. Bloc also has a part-time track, which allowed me to still work [a] full-time job while going to school.

– what is good about the job? What is challenging?

I appreciate the balance of being challenged but knowing I have the full support of any other engineer on the team if I need to reach out for assistance. Canvas United [ed: his current employer] has a lot of projects that I’ve been maintaining lately, and all are running different versions of Rails, which makes for interesting challenges. 

– what do you see current boot camp students doing that you’d advise against?

Not getting out and networking while going to school. This industry is all about networking and if you’re hoping to capitalize on the advantages of a good network you have to be building it while still in school.

– why did you want to transition into technology and development?

I wanted/needed a career path where the leaning curve wouldn’t plateau. I’m not a ‘cruise control’ kind of person, as soon as the challenge isn’t there for me anymore I lose interest.

– how can employers help boot camp grads in their first job?

Be ok with answering questions, and be transparent with the employee about the proper channels to ask those questions. Also, be upfront about the fact that it’s ok to fail (assuming that’s the case) a few time before you get to the best solution [ed: if it isn’t ok to fail, find a new job!]. Also also, a healthy balance of low hanging fruit and multi-day problems. Nothing kills my morale faster than ticket after ticket of problems that grind me into the ground.

– should employers have any different expectations of a boot camp grad vs someone who just graduated from college or high school?

I definitely think that it takes a particular type of management style to successfully level up a boot camp grad. If you’ve hired them you must have liked something about them, play to those strengths, but also sprinkle in challenges to help that developer evolve.

[This content has been edited for grammar and clarity.]

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