Web Developer Intern

Mosaic Conseil is a remote workshop dedicated to rebuilding business artifacts with absolute precision. We do not produce slide decks or participate in the typical cycle of corporate meetings. Instead, we take existing plans, pricing grids, and financial models, take them apart on the bench, and put them back together based on the hard evidence of the ledger. Our partner is a major Spanish infrastructure firm, and this engagement requires a high level of technical focus to ensure that their digital assets and data models are as sturdy as their physical networks. We remain small by choice, ensuring that the people who do the work are the same people who handle the results.

About Mosaic Conseil
We operate as a boutique consultancy where the work is personal and focused. Every file we close carries two names: one person who built the model and one who argued against it. This builder and challenger dynamic is at the heart of our culture, ensuring that no assumption goes untested. Because we are a fully remote team, we prioritize written arguments and deep work over the distractions of a traditional office. We focus on four specific areas: financial services, healthcare systems, growing software companies, and industrial networks. Our commitment to independence means we stay away from standing retainers and focus entirely on the evidence found at the floor of a business.

What you would do
In the role of Web Developer Intern, you will focus on the digital side of our artifact reconstruction. You will assist in building and maintaining internal tools that help us audit complex financial data for our partner, a major Spanish infrastructure firm. This involves creating clean, functional web interfaces that allow our team to visualize ledger entries and network data effectively. You will not be building marketing sites, but rather functional, data-driven applications that support our written arguments. You will also participate in our peer review process, serving as either a builder or a challenger for code and logic. This ensures that the tools we use to advise our partners are as reliable as the advice itself. Since the role is fully remote, you will be expected to manage your development tasks independently while keeping documentation clear and concise.

What you will do

• Develop and maintain internal web-based tools to process and display infrastructure data.
• Translate complex spreadsheets and financial artifacts into functional web interfaces.
• Write clean, documented code that follows our standards for precision and clarity.
• Collaborate asynchronously with senior partners to refine tool requirements.
• Act as a challenger for existing codebases, identifying potential logic errors or performance issues.
• Ensure all digital artifacts for our Spanish infrastructure partner are secure and accurate.
• Assist in the migration of static data files into interactive, searchable internal databases.

Helpful background
We are looking for someone who finds satisfaction in technical clarity and logical structure. You should have a basic understanding of the core building blocks of the web, specifically HTML, CSS, and JavaScript. While you do not need years of professional experience, you should have a portfolio of projects or academic work that demonstrates your ability to build a functioning web application from the ground up. An interest in how businesses are modeled and how financial data is structured will be very helpful in this role. We value the ability to write a clear explanation of a technical problem just as much as the ability to solve it. A curious mindset and a willingness to have your work challenged are essential traits for success in our workshop.

How we work
Our remote environment is designed to protect your time and focus. We do not have standing meetings, and we communicate primarily through written arguments and technical documentation. This allows every team member to engage in deep work without the constant interruption of notifications. When a project begins, we assign a builder and a challenger. If you are building a tool, your colleague will spend time trying to find where it fails or where the logic is weak. This is not a personal critique but a necessary step to ensure our work for the Spanish infrastructure firm is beyond reproach. We value intellectual honesty and the discipline required to work independently from anywhere in the world.

What the role offers
This is a paid position, and we offer a competitive rate that is attractive for an entry-level or internship role in the current market. Because we are fully remote, you have the autonomy to structure your work day in a way that suits your productivity. You will receive direct mentorship through our builder-challenger model, working closely with experienced professionals on high-stakes infrastructure projects. There is no corporate theater here: no unnecessary hierarchy, no slide decks, and no busywork. You will see the direct impact of your code on the artifacts we deliver to our partners, gaining a unique perspective on the intersection of web development and high-level business analysis.
The work we do at Mosaic Conseil is quiet, intense, and focused on the evidence. We believe that by staying small and remote, we can provide a level of analysis that larger firms simply cannot match. We look for interns who are ready to move past the surface level of development and engage with the underlying logic of how businesses function.