Open-Source Software: Pros, Cons, and What Most Teams Miss

A product team I once worked with pushed a release at midnight. Everything looked fine during internal testing. By morning, production was down.

The root cause was not bad code.
It was an open-source dependency that had changed quietly overnight.

No warning. No support number to call. Just a GitHub issue thread and a growing sense of panic.

If you’ve worked in software long enough, this story probably feels familiar. Maybe it wasn’t a midnight deploy. Maybe it was a security audit. Or a scaling issue that surfaced right before a board meeting.

You already know open-source software powers most of what we build today. You also know how much freedom it gives your team.

But here’s the uncomfortable question most teams avoid until something breaks:

Are we using open-source intentionally, or just inheriting it by default?

I’ve seen open-source unlock speed that no proprietary tool could match. I’ve also seen it slow teams down when ownership, governance, and long-term planning were never defined.

The difference is not the software.
It’s the decisions around it.

In this guide, I want to walk you through the real pros and cons of open-source software, and more importantly, the things most teams miss when they adopt it. This is not about choosing sides. It’s about making smarter decisions that hold up when your product, team, and responsibilities grow.

Before we go deeper, let’s ground this in how software is actually built today.

Open-source software is no longer a side option. According to IBM, citing a study from the Linux Foundation-

70–90% of a typical software codebase is made up of open-source components.

That number surprises many teams. Not because they don’t use open source, but because they don’t realize how much of their system depends on it.

So if you’re building software today, you’re already using open-source software. The real difference between teams is not if they use it. It’s how intentionally they manage it.

Here’s a simple way to think about it.

Using open-source software is like living in a well-built house where most of the materials came from a shared community. The structure is strong. The design is proven. But there’s no default maintenance team. When something breaks, your team owns the fix.

That responsibility is easy to overlook.

Many developers experience open-source as speed and freedom. They can move fast, avoid vendor lock-in, and build on tools the community has already tested. Executives often feel the weight later, during audits, security reviews, or outages, when they realize how much of the system relies on components no one formally owns.

Open-source software is not risky by nature.
But unmanaged open-source is.

When teams understand this early, open-source becomes a long-term advantage. When they don’t, it quietly turns into technical and organizational debt.

Most teams don’t adopt open-source software because of ideology. They adopt it because it works.

• Speed Without Waiting

When teams need to move fast, open-source helps immediately.

There’s no long sales cycle. No approval chain. Developers install what they need and start building. Startups use open-source frameworks to launch products in weeks instead of months.

That speed can decide who wins the market.

• Lower Cost at the Start

Open-source software usually has no license fee. That matters, especially early on.

Instead of paying vendors, teams invest in people and infrastructure. For startups and growing companies, this flexibility is hard to ignore.

• Freedom to Customize

With open-source, you control the code.

If requirements change, you can adapt. If performance becomes an issue, you can optimize. If a feature is missing, you can build it.

That level of control is rare with closed tools.

Here’s the part many teams don’t plan for.

Open-source works best early. The problems usually appear later, when systems grow, and teams change.

• Ownership Gets Blurry

When a critical open-source dependency fails, who owns the fix?

I’ve seen teams rely on one engineer who “knows how this works.” When that person leaves, the system becomes fragile overnight.

• Support Is Not Guaranteed

Community support can be great. It can also be slow or incomplete.

If your system goes down at a critical moment, there is no guaranteed response time. For internal tools, that may be fine. For customer-facing systems, it’s risky.

• Hidden Costs Appear Over Time

Open-source software is free to use, but not free to maintain.

Costs show up in:

• Training new hires
• Managing upgrades
• Auditing licenses
• Fixing breaking changes
  
  

These costs are real. They’re just delayed.

Here’s a simple way to look at it.

There is no universal winner.

Open-source works best when teams have strong technical ownership. Proprietary tools work best when teams need predictability and support.

Many people assume open-source software is either very secure or very risky. Reality sits in the middle.

Open-source code is visible. That means issues can be found faster. It also means attackers can study it too.

Security depends on:

• How active the project is
• How fast issues are patched
• How carefully your team updates dependencies
  
  

In regulated industries, this matters even more. You need processes, not assumptions.

As Bruce Schneier, a well-known security expert, puts it:

Security is not a product, but a process.

That applies strongly to open-source software.

This is the part most teams postpone.
And it’s usually the part that slows them down later.

Every open-source project comes with a license. That license defines what you can do with the code and what obligations you take on when you use it. Some licenses are permissive. Others are restrictive. Many teams don’t fully understand the difference at the start.

Here’s what usually happens.

A product is built using several open-source libraries. Everything works well. Then a compliance review, enterprise client, or acquisition discussion begins. Suddenly, questions come up about licenses, source code disclosure, and legal risk.

That’s when teams realize no one has been tracking this properly.

Licensing issues rarely break systems overnight. They delay releases, slow down deals, and create uncertainty at the worst possible time.

The fix is not complex:

• Track open-source dependencies early
• Know which licenses you’re using
• Review critical components before they reach production
  
  

When licensing is treated as part of normal engineering work, it rarely becomes a problem. When it’s ignored, it becomes a business issue instead of a technical one.

Most teams don’t struggle with open-source because of the tools.
They struggle because no one truly owns it.

That’s the part many teams miss.

Open-source is often adopted to move faster. Early on, it works. But over time, responsibility becomes unclear. Dependencies grow. Original decisions fade. And suddenly, no one knows who is accountable when something breaks.

Strong teams think differently.

They assign ownership.
They document decisions.
They plan updates instead of reacting to them.

They understand that open-source is not a one-time choice. It’s an ongoing commitment.

The biggest mistake is treating open-source as “set and forget.” It changes constantly. Maintainers leave. Dependencies evolve. Risks appear quietly.

Teams that plan for this stay in control.
Teams that don’t feel the impact later, when changes are costly, and trust is harder to rebuild.

There’s no universal answer here.
The right choice depends on your team, your risk level, and your future plans.

Before you decide, ask yourself a few honest questions:

• Do we have clear ownership for the open-source tools we rely on?
  
  
• Can we maintain and update them if key people leave?
  
  
• Are we prepared for security reviews and compliance checks?
  
  
• Do we understand the licenses behind our core dependencies?
  
  
• Is speed more important than long-term predictability right now?
  
  

If your team has strong technical ownership and discipline, open-source software can be a powerful foundation. It gives flexibility, control, and room to grow.

If your team needs guaranteed support, clear accountability, or operates in a highly regulated environment, a proprietary or hybrid approach may be safer.

In most real-world cases, the best answer is not one or the other.
It’s a thoughtful mix, chosen intentionally, not by habit.

Open-source software is no longer optional. It already sits at the core of how modern systems are built.

The real question is not whether you should use it. It’s whether you’re ready to own it.

When teams treat open-source as a strategic choice, it unlocks speed and innovation. When they treat it as a free shortcut, problems appear later.

If you’re evaluating your current stack or planning your next system, take the time to decide intentionally. That decision will shape your product far longer than any tool choice.

If you’re unsure how open-source fits into your current or future systems, a simple review can go a long way. At Mediusware, we help teams review how open-source is being used, who owns it, and where long-term risks may exist. Often, a simple, honest assessment is enough to prevent future surprises.