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Mobify Developer Values

What is the purpose of this document?

Why do we build software? Ultimately, it's to provide value to people. Sometimes, it can be hard to justify certain approaches to building software. The purpose of this document is to relate the "how" of building software to the "why" by relating our processes to our company values.

This is a living document. Everyone can contribute and as our company and culture evolve, so should this document.

This document will be helpful for:

What the document is not:

  • A set of rules. This is a guidebook, not strict set of rules that must be obeyed at all costs. For a great video on why to avoid blindly following rules, checkout Beyond PEP8.
  • Permanent. This is a living document that is always welcome to pull requests.

Developer's Perspective on Mobify's Core Values

Put Customers First

Know your customer and always act in their best interest. Customer, end user, partner and Mobifyers!

Write tests

  • Despite seeming like they slow down development, it's our experience that it speeds up overall development because it significantly reduces the danger of future changes, meaning we can ship future changes quicker and with greater confidence.
  • For example - capture.js is a very complicated piece of code that needs a bug fix every once and awhile. With tests, we can quickly make changes and ship with confidence.
  • Tests also help us write better code. Nothing helps refactor a giant method better than writing a test for it!

Build testable and well tested software

  • Test that the functionality you implemented works and fulfills the requirements. Also make sure that you didn't introduce regressions.
  • Software should have basic unit tests and continuous integration tests.
  • Make sure that any code that goes into production has been tested in a "real” environment, for example:
    • For JavaScript client libraries/frameworks, understand what devices are the most important for the code that you're writing. Once you have that understanding, test your code on these platforms with real devices. Using just Saucelabs or simulators is sometimes not enough.
    • For back-end code test on a staging environment that mirrors production very closely.
  • Be specific about dependencies. If you are including an external library, be explicit about the version of that dependency. Non-explicity versions like ~0.2.1 can lead to different behavior from one test run to the next if that dependency version changes.

Use staging / testing environments.

  • We should always test in an environment as close to production as possible before going live – this allows us to spot any bugs, and resolve them before we flip that switch and turn it on for everyone.

Fail Gracefully.

  • Adaptive.js/mobify.js projects fail gracefully by reverting to the desktop site in the event of an exception or network error.
  • If Web Push is down, the worst thing that happens is that you can't send or receive push notifications. It will not impact the critical flows of our customers sites.
  • Ensure failed analytics calls (caused by adblockers) don't cause main application business logic to fail.
  • Occasionally, things are going to blow up. It's important to have appropriate fail-safes to allow us to resolve issues as quickly as possible. Some examples of that are:
    • Kill switches or circuit breakers.
    • Forced updates to websites/apps when certain changes being made are not backwards-compatible.
    • Being able to rollback quickly (for example, make sure microservices are served off a domain you control. Not doing this has bit us in the past)
  • When things do blow up, have a post-mortem. Post-mortems are our best way of evaluating what processes caused failure to happen, and what we can do to prevent it from happening again in the future. Here is a list of post-mortems.

Build reliable services.

  • We want to be able to comfortably sleep at night without worrying about services falling over. That means:
    • Setting up monitoring and alerting
    • Setting up failover databases/servers
    • Practicing failures through Failure Fridays
    • Ensuring every major service has a Holy Shit Handbook.

πŸ€” Prioritize End-User Experience over Developer Experience

Sometimes, it's tempting to improve the codebase at all costs, but there is one cost that should never be compromised: the user experience. Ensure code changes you make to improve the developer experience don't come at the cost of slowing down the UI for the end user.

πŸ”’ Build Secure Software

With great power comes great responsibility. – Uncle Ben

Customers trust us with unlimited power when they use Mobify to power their websites. Breaches in our security would impact them and their shoppers. We have a great responsiblity to protect this trust:

😱 What should I do if I believe we have been compromised?

Get LOUD! Let Mobifyers in #security and #everybody know what you think is happening.

You may not be the only Mobifyer under attack.

Physically stand up and say IRL, "I think we're being hacked!".

No one is going to get mad at you for reporting security incidents.

Work with #security to investigate and change your critical passwords ASAP.

Be Exceptional

Be exceptional in your work, your communication, your development and to each other. Strive for excellence and quality in everything you do.

πŸ‘³πŸ½πŸ‘¨β€β€οΈβ€πŸ‘¨πŸ‘©πŸΏπŸ‘­πŸŒˆ Promote diversity and collaboration

Be excellent to each other... and... PARTY ON, DUDES! - Abraham Lincoln

We value diversity and collaboration. Our best work is done together, when all voices are heard.

  • Assume positive intent.
  • Be friendly and patient.
  • Be welcoming.
  • Be considerate.
  • Be respectful.
  • Be mindful of the words you choose.
  • When we disagree, try to understand why. – Django Code of Conduct

To understand what we're trying to become, it may be useful to understand what we're trying to avoid. See effects of contempt and competition on environments.

Constantly strive to become a better developer.

  • Always be learning.
    • Use your education budget. It's there for you to level up in areas that might be hard to level up at in your day to day work.
    • Constantly learn new languages, techniques, frameworks, methodologies, leadership skills, domain knowledge, etc. Doing it in a structured way (a course/tutorial, join or start a Mobify Study Group) is preferred over reading endless Hacker News articles.
  • Teach others and help them grow in their abilities.
    • Teach your co-workers. Good venues for this are Science Fair or the Engineering Meeting.
    • Teach the community - for example speak at meetups (VanJS), VanPy, Web Performance, etc) or write blog posts.
    • Transfer knowledge whenever possible. If someone encounters a problem it is better to guide them to a solution rather then solving it for them.
  • Code reviews and Pair Programming are excellent strategies for learning new tricks.
    • Ensure people with different skill levels and skill sets are reviewing your code, it's a great opportunity for cross-pollination.
    • Get your code reviewed by the CTO at our Engineering Office Hours.
    • As the person receiving feedback, strive to be as open to the feedback as possible. This will help maximize learning. (Note: that is not a license for reviewers to completely disregard the feelings of the person who wrote the code - we believe that relationships are more important than process or tools).

Build and work on your career growth plan

Be a software craftsperson

  • Take pride in how you build the software and your craft regardless of how the product does in the market. This doesn't mean gold-plating everything, often you should act pragmatically. Shipping value to users is the most important thing, but make sure to take the time to reflect on what you build, and do a post mortem and always make sure you're not repeating the mistakes of the past.
  • Ensure you challenge designs that you see problems with instead of implementing them without questioning.
  • Internet resources such as StackOverflow and Github are valuable as a source of advice and example code, but we don't treat them as a source of truth. We always try to understand and validate what we find online before using it (using available source code and API documentation).

Be in touch with the dev community

  • Go to meetups and conferences and share what you've learned with the rest of the team.
  • Write blog posts or speak at meetups and conferences.

βœ… Use checklists

There is plenty developers can learn from pilots - one is that our memories are faulty and unreliable, leading to inconsistency.

Checklists are a great way to ensure consistency, in areas such as:

Checklists are also the first step towards automation - lists help you realize which repetitive tasks could be scripted.

Keep it Simple, Silly (KISS)

  • Simple is better than complex.

You Ain't Gonna Need It (YAGNI)

  • Don't build stuff until you need it.
  • Design software for ease of extension and contraction. A great way to do this is to optimize for "throwaway-ability".
    • e.g. make the new thing modular and self contained, and not require modifications to shared dependencies. Once it's clear things are going to stick, then think about refactoring things once it is clear that they are going to "stick".

Don't repeat yourself (DRY)

  • Extract common or shared functionality into utility functions, and if needed across multiple projects, extract into libraries or frameworks.
  • Re-use the things you've built and avoid copying and pasting. For example we don't want duplicated functionality in our functions, classes, modules, systems. We also want to avoid duplication and share code across sites/apps/systems.

Improve Process

The way we're doing things today is based on information we had in the past.

New people, tools and understanding changes the context in which the decision was made.

The way we decided to do things last year, last month or even last week might not be the best way to go forward today.

If you have idea for how to improve a process, work with your team/lead/peers to make it happen!

Scouts Rule

Try and leave this world a little better than you found it. – Robert Baden-Powell

Continuously improve through iteration.

Can that function you touched be refactored? Can the doc strings of the module you changed by updated? Are there inconsistencies in naming of files you're editing?

Try and leave this code a little better than you found it.

Be wary cleanup doesn't hide the intent of your change!

Own It.

Own the challenge, the solution, the feedback, the decision, the outcome. Accountability at all levels.


  • For a service, app or site that goes live, no one is going to fix your production bug but you. At Mobify, we practice DevOps, meaning engineers are responsible for both building software, and making it operate live in production. There is no central Operations team for running/maintaining production code, although we do have a DevOps guild that gets together to discuss our different services.

πŸ‘₯ Seek Feedback

In medicine there is a tradition, where πŸ‘©πŸΎβ€βš•οΈ doctors, no matter how experienced, ask colleagues for a consult: an opportunity to hear another perspective on how to resolve a challenge.

Mobify has blatantly stole this great tradition.

Actively seek feedback and incorporate it into your work.

Before implementing a major change, discuss solutions with your peers.

Discussions may be informal five minute πŸ¦† Rubber Duck sessions in front of a white board, or an in-depth Project Technical Review with your team and πŸ– stakeholders.

Early discussion stops us from pursuing dead end solutions.

We call this up front planning 30% Feedback.

Whether written by the CTO or most junior Mobifyer, all code is reviewed before being deployed to production.

πŸ™ Embrace feedback. It is crucial to your growth.

Reach out to domain experts.

  • We value a collaborative development environment where we seek expertise from domain area experts. We have a wealth of expertise on the team with very talented folks - talk to them instead of making the mistake yourself! If you are unsure who to chat with, feel free to reach out to folks in the Engineering room on Slack, or reach out to your lead.

Readability counts.

  • Code is written once but read often. There is a good chance someone will have to figure out what it does, mostly likely you, twelve months from now. Take care to write your code in such a way that your future self can iterate on new features and address bugs much faster.
  • Follow the Mobify Style Guide. It contains best practices, as well as linter tools for various commonly used languages - we highly recommend using those tools instead of hearing about code style issues in PR reviews! Please feel free to open up PRs against it - our style guide is an always-evolving document!
  • Explicit is better than implicit.
  • Your code should "fit” with the rest of the codebase. Use an idiomatic style that is understood by the rest of the team.
  • Write comments!
    • Code that reads like pseudo code doesn't need comments, but complex logic does.

    • Comments explain what Β the code is doing and why Β it's doing it, but not usually how Β it's doing it.

    • Comments shouldn't repeat what your code should already be saying. As long as you're being explicit with your variable naming, something like this is not necessary:

      // if we are running in an app, do "blah”
      if (isRunningInApp)

Build systems that are easy to maintain.

  • Code is written once but read often, meaning more time is spent maintain software than there is in writing it.
  • "Standardize how things are deployed" (for example, it's better to put a new service onto Heroku than to just run it on a physical machine in the office).
  • Be consistent. The projects which are the easiest to work on are the ones that have a consistent code style and structure. It's problematic when the style across different parts of the codebase is completely different. To do this, refer to other parts of this document, as well as the Mobify Code Style repo.

✏️ Write Great Documentation

Documentation is essential to a codebase accessible for new contributors.

All projects, modules, libraries and plugins must include a file in the root folder. Minimum viable documentation includes:

  • πŸŒ‹ Interpretation of the project name in beautiful ASCII art.
  • πŸ€” The purpose of the project.
  • πŸ‘‹ Who the owner of the project is, and where to ask for help.
  • πŸ— Steps to setup the project. Should be one command.
  • πŸƒ Steps to run the project. Should be one command.
  • πŸ› Steps to test the project. Should be one command, hooked up to continuous integration.
  • πŸš€ Steps to deploy the project. Should be one command, hooked up to continuous deployment.
  • πŸŽ– Steps to contribute to the project. Use

Draft your documentation before committing any code!

Be solutions focused

  • Rather than thinking "Wow, I can name 20 things that are awful with this design", try to be solutions focused. "There are 20 improvements we could make to this! X is done this way, but it could be better if we made it more like Y". There are many reasons why a piece of software was built the way it was built, and harping on how it was built doesn't get us any closer to solving the problem at hand.

Build Minimum Viable Products (MVPs)

When beginning a new feature with a high amount of ambiguity or uncertainty about whether it will really be a hit, think "What is the MVP for this" that is, what is the minimum amount of work we can do to deliver the value of this feature to the user.

In other words: Don't gold plate before validating your idea.


Think we should do X? Build a prototype and convince people. Slack discussions, Science Fair, or the Engineering Meeting are excellent avenues for this.

Release early, release often

The best way to debug software in production is by releasing it and identifying the bug right away, rather then waiting a month and then completely forgetting how things worked.

Caveat: Release within reason. You can ship a backend feature multiple times a day, but you might not want to release 5 versions of Adaptive.js in a day. Use discretion.

A feature in the hands of our customers is worth more than 5 PRs.

When working on a team, it can be easy to crank away on your own features. Resist the urge! It's more important to get some work merged and in the hands of users then it is to have a bunch of work piled up for review. This article on code review explains it best.

New problems don't require new technology

When building software that solves a problem, it's unlikely that you need new technology to solve it. The things you are building should be pushing boundaries, not the things you are building them with. By default, you should choose boring technology.

To make such technology decisions easy, it's important to maintain a set of best practices outlining what technology to use when solving particular classes of problems.

Mobify best practices can be found here.

Avoid re-inventing the wheel

  • Look for existing solutions Β (libraries, snippets, services) before rolling your own. If they exist, someone will likely know - reach out to the Engineering team early and often!

Have an idea you want to pursue?

  • Customer/Product Improvements:
  • Software Improvements - new patterns, libraries, frameworks, or services to improve existing products.
    • Reach out to your peers (Infrastructure Guild, Eng Meeting, Eng Room, Science Fair, Astro/Web Dev Sync)
  • Self Improvements
    • If it’s an idea that aligns with your career growth plan (learn a new language, write a blog post, speak at a conference), be sure to ask your lead how they can support you in achieving your goals.

The Zen of Mobify

  • Be excellent to each other.
  • Be concise.
  • Avoid acronyms or jargon where words would do.
  • Favour small diffs over big bangs.
  • Why argue when you can experiment?
  • Open by default.
  • Small, empowered teams are unstoppable. Let's make more of those.
  • New problems don't require new technology.
  • Don't take this all too seriously.


πŸ™Œ Principles to follow when building software.




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