Which is Right for You? A Thorough Comparison of Programmer Job Types: SES, Contract Development, and In-House Development

When programmers and engineers consider changing jobs, their work style options are generally divided into three main categories: "SES (System Engineering Service)," "Contract Development," and "In-House Development."

However, while many may know these terms, surprisingly few may accurately understand the differences in specific job duties, career paths, benefits, and drawbacks.

Even the phrase "an environment where you can skill up" means vastly different things depending on the business model. To prevent a mismatch after changing jobs and build a career that truly suits you, let's first firmly grasp the characteristics of each.

1. SES (System Engineering Service)

SES is a contractual arrangement where engineers belonging to one company are stationed at a client's office, which requires their technical skills, to provide technical services (labor). A key feature is that while the employment contract is with their home company, the actual work is performed at the client's site.

Benefits

• Experience Diverse Environments: You may have the chance to participate in projects of various industries (finance, manufacturing, communications, etc.) and scales in short periods. This broadens opportunities to touch upon diverse business knowledge, different development environments, and varied technologies.
• Easy to Expand Your Network: By working at multiple client sites, it's an environment conducive to building a network with external engineers and contacts.
• Accessible Even with Little Experience: Due to the wide variety of projects, there's a tendency to find roles available even for those with relatively little experience.

Drawbacks

• Tendency for Unstable Environments: Working hours, development rules, and workplace atmosphere change significantly depending on the client site. You must adapt to new relationships and rules every time a project changes.
• Decreased Sense of Belonging: Since most time is spent at the client site, the sense of belonging or attachment to your home company (the one you're employed by) can easily fade.
• Career Fragmentation: As job content changes with each project, it can be difficult to deeply pursue one specific technology or product.

2. Contract Development (Outsourced Development)

Contract Development is a work style where a company receives an order from a client ("We want you to build this system"), develops the system or software, and delivers it as a final product. Development is primarily carried out at your own company's office.

Benefits

• Easy Involvement in the Full Development Lifecycle: A key attraction is the ease of experiencing the entire project flow, from requirements definition with the client to design, development, testing, and delivery.
• Exposure to Diverse Industries: Similar to SES, you can acquire broad domain knowledge and problem-solving skills through client work across various industries.
• Sense of Accomplishment: Working as a team to complete and deliver a product by the deadline brings a great sense of achievement when the project is successfully concluded.

Drawbacks

• Deadline and Budget Pressure: Being client work, development must proceed within the constraints of set deadlines and budgets. Schedules tend to be tight, and there are periods when overtime increases.
• Low Freedom in Technology Selection: The technologies used are often specified by the client's requirements, existing systems, or budget, meaning you can't always pursue the latest technologies.

3. In-House Development (Internal Product Development)

In-House Development is a work style where you develop web services, applications, or software that your own company plans and operates. In-house engineers perform development tasks for the growth of their company's own products.

Benefits

• Product Attachment and Sense of Contribution: You get involved with a single product long-term, allowing you to feel the satisfaction of "nurturing" a service. User feedback often comes directly, making it easy to see the results of your work.
• Involvement in Planning and Tech Selection: There tend to be many opportunities for engineers to proactively participate in the service's direction, planning new features, and selecting technologies to implement.
• Stable Development Environment: Unlike contract development, which is chased by deadlines, schedules are comparatively easier to control, allowing you to settle in and focus on quality improvement and resolving technical debt.

Drawbacks

• Bias in Technologies and Domains: The technologies and business domains used for the in-house service can become fixed, making it difficult to broaden your technical range unless you consciously study.
• Service Success/Failure Directly Impacts Business: The company's revenue depends on its in-house service, so if the service doesn't succeed, there's a risk of poor business performance.
• High Level of Skills Required: You are often expected to be an immediate contributor, not just in development but also in proposing service improvements, so the hiring hurdle tends to be high.

Conclusion: Which Fits Your Career Plan?

SES, Contract Development, and In-House Development. There is no absolute answer as to "which is best" among these three work styles.

• If you "want to experience diverse environments anyway and find my aptitude," choose SES.
• If you "want to face clients and learn the entire product creation process," choose Contract Development.
• If you "want to grow attached to one service and nurture it carefully," choose In-House Development.

As you can see, the optimal choice changes depending on your current skill level and your future career plan for what kind of engineer you want to become.