When talking about serverless, cost savings and auto-scaling are the first benefits that come to mind. Companies expect reduced operations time and lower costs to deliver more value on features critical to their business.

A dream (at least for investors).

I guess you’ve read this theory a few times already. And still, how can you be sure that serverless is the right fit for you? That your use case is indeed cheaper with serverless?

Today I will shine some light on how much an AWS serverless architecture could cost you. To help with that, we (at Theodo) created an easy…


Talking about serverless architecture goes way beyond Function as a Service (FaaS) like AWS Lambdas.

Two of the reasons why Lambdas are so attractive are their auto-scale (in & out) capability and their pay-per-use pricing model. In order to leverage these capabilities and reach the full benefits of a serverless architecture, we need our other infrastructure components to have the same flexibility.

What would such an architecture look like on a web project?

At Theodo, we’re loving serverless and using the technology on more and more projects. Some services and patterns start to be used extensively. So we decided to…


The event-driven paradigm is usually adopted with serverless architectures, dispatching asynchronous events to trigger wanted effects.

This behaviour comes natively with most AWS services:

  • if someone uploads a picture on your S3 bucket, you can make a Lambda listen and react to this event
  • if a Lambda adds a new object to your DynamoDB table, you can react in the same way

And when developing your micro-services, we find it best to connect them with the same pattern:

  • when a synchronous Lambda (for example inviteUser) dispatches an event through EventBridge triggering another Lambda (such as sendEmail) (Side note: why EventBridge…


At Theodo, since April 2018, we have been developing libraries of shared React components for one of our biggest client. We proved the value of maintaining such a project and stabilised its architecture and configuration.

Through this article, we want to share what a project of shared component means and in what situation is it worth doing one.

What is a shared components project?

If you are a developer, go to the next section.
If not, you might not know that apps are composed of two sources of code:

  1. Custom code
    Business specific code meant to solve a problem in a new way.


Every time I talk about my travels I end up talking about how happy it made me to be well prepared. This good organisation has a lot to do with a “few” bullet points I laid on my phone notes.

A year ago I traveled to Vietnam with my girlfriend and we forgot so many little things that would have made our life easier during the trip without impacting our mobility that I started to list all those necessary little things to make sure to never forget any.

The list grew. It helped us a lot. People around showed interest…


With Fontello/Icomoon and react-native-vector-icons

With this article you will be able to add and use handmade icons inside your React Native application in no time.

I- Create your icon(s)

With a vector editing tool (like Illustrator), create your custom icon.

A nice Toad for our app !

Then export it as a normal SVG but make sure you export each icon with the same squared art-board size.


I recently worked on a performance project for a client. In this article I will detail the context of the project and explain what we learned and implemented, hoping it can help some of you.

Some context

The app:

  • An internal financial tool for a big company letting managers view and update workload costs per projects and departments. Therefore a lot of dynamic data computation and representation through tables. …


This article is the third of a series aiming to answer to What is Analytics, Why, When and How to use it

In my previous articles, I explained why Analytics is such a great tool to help drive a product, and then I detailed why I think Google Analytics (GA) is the perfect platform for this matter.

Let’s now dive into the technical implementation of Google Analytics for React Native.

At the bottom of the article I talk a bit about tracking with Google Tag Manager, and then I mention Firebase which is a new Google tool for doing Analytics…


This article is the second of a series of three articles aiming to answer to What is Analytics, Why, When and How to use it

In my previous article, we discussed why Analytics is a great mean to drive your product. We will now take a look at one of the most famous Analytics tool.

The purpose of this article is to give you a brief but nonetheless actionable knowledge of what you can do with Google Analytics (GA), and at first, why you would use GA.

Why this tool?

Before even digging into the tool itself, let’s detail why you would use…


This article is the first of a series of three articles aiming to answer to What is Analytics, Why, When and How to use it

It is no news to say that understanding your customers needs and behavior and addressing them is one of the main keys toward business success. In the software industry, User Experience (UX) Research provides a great framework for this matter. Analytics is part of this set as the principal quantitative source of user insight.

This series of articles aims to give you a beginning of answers and knowledge about Analytics, from its purpose to its…

Xavier Lefèvre

⚙️ Tech Enthusiast — 👨‍💻 Product Lead @ Inato — 🏍 Motorcycles Lover — 🏮 Traveler

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