Mosaic Conseil operates as a small, remote workshop dedicated to rebuilding business artifacts. Whether it is a pricing grid, a three year plan, or a complex diligence file, we take things apart on the bench and put them back together against the evidence of the invoice ledger. Our process is personal and focused. We do not work on standing retainers and we do not produce slide decks. Instead, we return the same artifacts our clients sent, redrawn and supported by a written argument. We focus on four specific rooms: financial services, industrial networks, growing software companies, and healthcare systems. Our partner is a leading Spanish telecommunications provider, and we are currently working with them to refine their internal analytical structures.

About Mosaic Conseil
We are a boutique remote consultancy where professionals rebuild business plans and financial models with precision. We prioritize written arguments and deep work over corporate theater. We keep the workshop small on purpose to ensure that the people who do the work also handle the communication. Every file we produce carries two names: one person who builds and one who argues against what was built. This ensures that every assumption is tested before a file closes. By staying small and remote, we remain independent and focused on the evidence at the floor of the business. Our work is handled on paper and backed by a telephone number that answers for ninety days after delivery.

What you would do
As a Frontend Engineer Intern, you will work within our software room to build the interfaces that house our financial and analytical models. You will be responsible for creating clear, functional web components that allow our clients, including our Spanish telecommunications partner, to interact with complex data artifacts.



This involves translating logical models into responsive and intuitive browser based tools. You will participate in our builder and challenger process, where you will either build a specific feature or act as the critical eye for a feature built by a colleague. You will write clean, well documented code that prioritizes utility and clarity over visual flair. Because we do not use slide decks, your frontend work will be the primary way our clients engage with our findings and arguments.

Helpful background
We are looking for individuals who have a strong foundation in web technologies and a high degree of intellectual curiosity. For this internship position, we expect the following:

- Basic proficiency in modern JavaScript frameworks such as React, Vue, or Svelte.
- A solid understanding of HTML and CSS, with an interest in data visualization.
- The ability to write clear, concise documentation for the code you produce.
- Familiarity with version control systems like Git.
- A logical mindset and the ability to follow a structured analytical process.
- Comfort working in a fully remote environment where written communication is the primary tool.
- An interest in how technical interfaces can clarify complex business logic.
- The ability to receive and provide critical feedback during the challenger phase of a project.

How we work
We operate as a fully remote team.



There are no offices and no scheduled meetings that do not have a clear, documented purpose. We value deep work and long periods of uninterrupted focus. Our builder and challenger dynamic means that you will never work in a vacuum: your logic will be tested and your code will be reviewed by someone whose job is to find the flaws. We believe this tension leads to better results for our clients. We communicate through written notes and focused calls. We do not use internal messaging for constant chatter: instead, we respect the time required to solve difficult problems. This role is a full time, paid internship, and we provide a competitive salary that is attractive for the current market and the level of responsibility.

What the role offers
This position offers a chance to work on high stakes projects without the noise of a traditional corporate environment. You will gain experience building tools that are used to make significant business decisions. You will have the autonomy to manage your own schedule within our remote structure. Because we do not have layers of management, you will be directly involved in the construction of the artifacts we deliver. We provide a space for technical growth where the focus is on the quality of the evidence and the strength of the code. You will learn to build software that serves a specific, analytical purpose, supported by a team that values intellectual honesty above all else.
Precision in our code reflects the precision in our arguments. We look for thinkers who find satisfaction in the details and who understand that a well built interface is an essential part of a clear business case. The work we do is demanding, but it is free from the distractions of meetings and decks, allowing for a focused professional practice.

📌 Frontend Engineer Intern (España)
🏢 Mosaic Conseil
📍 España