Senior Software Engineer (m/f/d) - SEtrade

Electricity cannot be stored. Generation and consumption must be balanced every second, otherwise the grid frequency collapses. This is not an attitude, it is physics.

This physics creates a market that trades in 15-minute intervals and shows no mercy. This is exactly where our software operates.

Today, we manage 350 MWp of solar, 100 MWp of wind, 100 MWh of storage, 12 MW of hydrogen, and over 40 HPC charging points. Each of these facilities delivers time series data. Time series data becomes forecasts, forecasts become schedules, and schedules become bids on the stock exchange. If one link in this chain is twenty minutes late, it costs money. Not story points. Money.

WHY THIS POSITION EXISTS

We have grown the platform from zero to 850 GWh in just a few years. In some areas, we consciously built pragmatically because being on the market was more important than being clean. That was the right decision then.

Today, it is no longer the case. The same shortcuts that made us fast are now slowing us down. Tables designed for millions of rows are now handling billions. Process chains that someone used to initiate manually in the morning now run around the clock and must not fail.

We are not looking for someone to manage this. We are looking for someone to rebuild it while it is running.

Responsibilities

WHAT YOU ACTUALLY DO

• You decide how our systems are structured. Not in a committee, but by making the proposal, defending it, and then implementing it. Those who decide, build.
• PostgreSQL and TimescaleDB, schedules, measurements, market data. Schema, partitioning, aggregation, query plans. If a query takes eight seconds, that's a bug for us, not a feature.
• Forecasting, optimization, schedule transmission. Retry, idempotency, alerting. The standard is simple: whatever goes wrong at night must not require manual intervention in the morning.
• Connecting facilities. PV, storage, hydrogen, charging infrastructure. ModbusTCP, REST, SFTP. You'll talk directly with the customer's technicians to find the error together, rather than writing a ticket.
• At the end of the month, the same time series data turns into money. Market premiums, PPA and storage remuneration, levies, charging transactions, GHG quotas. Grid operators resubmit measurements, correct them, and send them a year later. Your processes must withstand this and deliver the same result on the second run as on the first.
• PHP with Laravel, React, PostgreSQL/TimescaleDB, Python. Tests, CI/CD, and monitoring are part of the implementation, not something you do afterwards.
• We use Claude and similar tools productively, not as a demo. You know from your own experience where they are useful and where they produce nonsense, and you pass that knowledge on to the team.

TRADING AND BILLING ARE ONE SYSTEM

The time series data that determines the schedule at 2:30 PM also determines what the customer gets paid at the end of the month. If both paths lead to different numbers, it's no longer a monitoring issue. That's when the auditor gets involved.

That's why this role encompasses both sides. Speed is paramount at the front end, and reproducibility at the back end: a billing run must be restartable after a year with corrected grid operator data and clearly explain why the result has changed. Versioned tariff and remuneration logic, idempotent rerun capabilities, clean assignment via MaLo IDs. Anyone who separates these creates two truths.

Qualifications

HOW WE WILL MEASURE YOU

After 90 days, you will have resolved a structural bottleneck, and it will be measurable.

After twelve months, new facilities will go live without special solutions, critical time-sensitive chains and billing runs will operate without manual intervention, and the developers around you will have improved. The last point is just as important as the previous two.

THE BAR

We have no requirement for your degree. We have one for your proof of competence.

• You have successfully guided at least one system through a scaling leap and were the one who made the architectural decisions. Five years of professional experience is our rule of thumb for this, not a condition. If you've achieved it in three, that's just as good for us.
• You have worked with time series data in the billions and know how a bad partitioning cut feels when it's two years old.
• You have built a process chain that runs at night without you. And you have experienced what happens when it doesn't.
• PHP with Laravel, React, PostgreSQL. Comparable experience in other languages counts just as much. We don't hire anyone because of a framework, nor do we disqualify anyone because of one.
• Git, Docker, CI/CD, automated tests, observability. Craftsmanship, not a project.
• German at C1 level, as you will be speaking with grid operators, customers, and market partners. English proficiency is required.
• You consider a code review a gift.

What we explicitly do NOT require

A specific degree. Certificates. A minimum number of years. And experience in the energy industry on your CV. Direct marketing, balancing energy, balancing groups, and billing logic can be learned here in months. We won't teach you technical judgment.

Show us a system, not a list.

Benefits

WHEN YOU WILL BE UNHAPPY HERE

• If you need a fully defined requirement before you start.
• If you wait for the perfect solution.
• If "it works on my local machine" means finished for you.
• If you see problems outside your area and consider them not your responsibility.
• If the title is more important to you than what actually runs productively in the end.

WHAT WE DON'T HAVE

No paragraph about fruit baskets. No eight approval levels. No architects who don't program. And no roadmap that pretends to know what the market will look like in two years.

WHAT WE HAVE

• An office in Munich where people actually work.
• Decision paths involving a maximum of two people instead of twelve.
• Modern AI tools as standard, not as a pilot project.
• Further training, maximum employer contributions to savings plans, company fitness programs. These are listed here because they are part of the package, not because they should be the primary reason.
• Prospects towards Lead Engineer or Software Architect as soon as the work allows.
• Problems that no one has solved for you yet.

APPLICATION

No cover letter. Send us three things:

1. Your CV or your profile on GitHub or GitLab.
2. A system you significantly co-designed, and in three to five sentences, the decision you most regret making about it today.
3. A point in this job posting that you believe is flawed in its conception.

Point three is meant seriously. We read it first.

YOUR CONTACT PERSON

Lara-Theresa Masur

+49 151 27657632

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