Building or Buying Billing Software: What Makes Financial Sense in the US?

It’s not always easy to decide to use a new billing system. It is at the crossroads of strict financial planning, operational efficiency, and customer experience. The current tools are starting to break down for a lot of US businesses that are growing because of new subscription models, complicated tax laws, and more transactions. At this point, you have a big choice to make: do you build a custom solution from the ground up or buy a ready-made one?

This isn’t just a discussion about technology; it’s a meeting about money. The decision to build or buy billing software will have an effect on your bottom line for years to come. We see this fight every day at MyFluiditi. We are an AI-driven web app development company, and we know that software needs to be more than just code that works; it needs to be a valuable business asset.

This guide will break down the financial effects of this choice on the US market in particular. We will look at the hidden costs of development, the problems with SaaS subscriptions, and why the market is moving toward hybrid, AI-enhanced solutions.

The main problem is between control and convenience.

The main point of the argument is the choice between having full control and being able to do things right away. Many US businesses, especially those that are growing quickly, find that off-the-shelf software gets them most of the way there. The last 20%-the specific workflows, the unique integration with legacy systems, and the branding needs-becomes the problem.

You are renting a solution when you choose to buy. You pay a monthly fee to have someone else take care of the infrastructure, security updates, and new features. It is easy to guess. But when you choose to build, you are putting money into an asset. You own the code, the data structure, and the plan.

To choose between building or buying billing software, you need to really understand your company’s DNA. Do you run a tech company that needs to stand out with its billing process? Or are you a service provider who just needs billing to work in the background and not bother you?

The “Buy” Argument: Speed and Certainty

Most small and medium-sized businesses (SMEs) buy software, usually through a Software as a Service (SaaS) model. There is no doubt about the appeal. You can sign up today and send bills tomorrow.

Immediate Use
Money is time. In the US, where getting to market quickly can mean the difference between success and failure, waiting six months for a custom build can be bad. When you buy something, you can skip the whole development lifecycle. You don’t need to hire a UX designer, a product manager, or a group of backend engineers. You just bring in your customer data and go live.

A Cost Structure That Is Easy to Understand
CFOs like things to be predictable. Most SaaS billing platforms charge a fee for each user or a percentage of the total number of transactions. This makes it easy to make a budget. You know exactly how much your operational costs (OpEx) will be next quarter. There are no surprise bills for server maintenance or emergency debugging.

Following the rules and keeping things safe
When you handle payments, you also handle sensitive data. This puts you in the realm of PCI-DSS compliance in the US, and possibly GDPR or CCPA compliance depending on where your customers live. Established billing companies have whole teams that work on compliance. When you buy, you’re basically passing on this huge liability to someone else.

But the “buy” model has a limit. As your income grows, transaction fees can get very high. A 1% fee on $100,000 is not too bad, but a 1% fee on $100 million is a big hole in your revenue bucket. Also, you are stuck with the vendor’s roadmap. You have to wait and hope they build it if you need a certain feature, like a unique prorated refund logic for a niche subscription.

The “Build” Argument: Personalisation and Value Over Time

Making your own software is a big step. It takes money, time, and technical know-how. But for some kinds of businesses, this is the only way to get things done quickly.

Full Customisation
Generic software won’t work for you if your pricing model is different. You might charge based on complicated usage metrics, like “compute hours used during peak times minus loyalty credits.” Off-the-shelf tools have a hard time with this level of detail. Custom software is like a tailored suit for your business.

No Fees for Each Transaction
The initial capital expenditure (CapEx) is high, but the long-term operational costs may be lower. You don’t have to give a vendor a cut of every sale. Once the system is up and running, your costs will be for maintenance and hosting, which are much easier to manage than fees based on a percentage.

Asset with a plan
Your company’s value goes up when it has proprietary technology. Investors will be very happy if you own your core technology stack, including how you make money, if you ever want to leave or get more money. It shows that you don’t rely on third-party platforms that could raise prices or go out of business.

Of course, the downside is risk. IT projects are well known for going over budget and taking too long. You are in charge of every bug, every time the server goes down, and every security patch.

Financial Breakdown: The True Cost of Owning

You need to look past the price tag to make a smart choice. We need to look at the Total Cost of Ownership (TCO) over a period of three to five years.

The Price of Buying
Let’s say you pick a well-known business billing platform.

Subscription fees: These usually go up as revenue goes up. A platform could cost $500 a month plus 0.8% of sales. If you process $10 million a year, that’s about $80,000 a year in transaction fees alone, plus the base subscription.
Costs of Implementation: Even “turnkey” solutions need to be set up. You could pay consultants between $10,000 and $50,000 to set up the software and move data.
Integration Costs: To connect your billing software to your CRM (like Salesforce) or ERP (like NetSuite), you may need middleware or pay extra for APIs.
Training: Employees need to learn how to use the new system.
The Price of Building
Now, let’s go over the custom route.

Development Team: A team of developers in the US (frontend, backend, and QA) could easily cost between $300,000 and $500,000 to build something for the first time over the course of six months. Using AI-assisted development or outsourcing can help with this, but it costs a lot of money up front.
You pay for cloud hosting (AWS, Azure, Google Cloud) as part of your infrastructure. This could cost between $1,000 and $3,000 a month for a medium-sized app.
Software gets old, so you need to keep it up. You should set aside about 15–20% of the cost of building the first time each year for maintenance and updates.
Security Audits: You are now in charge of making sure everything is up to code. It can cost more than $10,000 a year to do regular audits and penetration tests.

The Point of Break-Even
The math usually shows where the break-even point is. Buying is almost always better for the money for startups in their early stages. It costs too much to take your engineering team away from your main product.

But as sales go up, the lines cross. When a vendor’s transaction fees are higher than the cost of keeping a custom team, it becomes much harder to decide whether to build or buy billing software. The “build” argument gets stronger when a company makes more than $20 million to $50 million a year or has complicated B2B contracts.

The Hybrid Approach: How MyFluiditi Fits In
The market is no longer just two-sided. You don’t have to pick between a rigid SaaS product and a blank text editor. There is a middle ground: AI and modular frameworks speed up custom development.

MyFluiditi is an expert in this area. We think that the best financial choice for many US businesses is to use modern AI tools to build a lean custom solution.

We can do the following by using AI in the development process:

Cut down on coding time: AI coding assistants can make boilerplate code for payment gateways (like Stripe or PayPal integrations) in minutes instead of days.
Automate Testing: AI can run thousands of billing scenarios to make sure your logic works, which cuts down on the cost of QA.
Smart Features: We can put AI right into your billing tool. Think about a system that can tell when a client is going to be late on a payment or that can automatically suggest dynamic pricing models.
This method lowers the initial CapEx of building, which makes custom software available to businesses that would have had to buy generic tools before.

Scalability: Will It Keep Up With You?
One of the biggest worries when deciding whether to build or buy billing software is whether it can grow with your business.

If you buy, you are putting your faith in the vendor to grow with you. Most top-tier vendors can handle a lot of business. But they might not be able to handle your level of complexity. If you move to a new country with a tax law that the vendor doesn’t support, you’re stuck. You might have to come up with a hacky way to get around this, or you might have to run a separate billing instance, which would break up your data.

If you build, it’s up to you to make it scalable. You need to design the database architecture so that it can handle millions of rows of transaction history. You need to make sure that your APIs don’t stop working during Black Friday sales. But you have the ability to change course. You can code that logic right away if you start a new line of products with a pricing model based on how much they are used. You don’t have to wait for a vendor’s Q3 release cycle.

The Rules and Regulations in the US
There are a lot of different tax rules for businesses in the US. Laws about sales tax nexus are different in each state, county, and city.

Buying: Good vendors work with tax engines like Avalara or Vertex. They do the hard work of figuring out taxes. This is a huge “pro” for buying.
Building: If you build, you have to put these tax engines together yourself. Building a tax calculation engine from scratch is usually a bad idea because it will cost you a lot of money. A custom build should focus on your business logic and use specialised APIs to handle simple tasks like sending emails and paying taxes.
Why “Building” is Making a Comeback
For ten years, the trend was mostly “SaaS everything.” But now it’s starting to swing back a bit. Why?

SaaS Fatigue: Businesses are sick of having to keep track of 50 different subscriptions. Consolidation is very important.
The API economy makes it easier than ever to build. You don’t make your own payment processor; you use the Stripe API. You don’t make your own tax engine; you use the Avalara API. You don’t make your own email server; you use SendGrid. Building” these days really means “orchestrating APIs.”
Data Sovereignty: Businesses want to own their data so they can analyse it. It can be hard to get information from a third-party vendor’s walled garden. You can run deep learning models on your customers’ payment habits to lower churn if you own the database.
When you look at building or buying billing software from the point of view of data ownership, building gives data-driven companies a clear edge over their competitors.

Case Studies: When to Change Directions
Let’s look at two made-up examples that are common in the US market.

Scenario A: The New Online Store

Selling mugs and t-shirts is what they do. $2 million in sales each year. Regular transactions.
Decision: BUY.
Reason: Their billing needs are normal. Everything is taken care of by Shopify or a similar site. It would be a waste of time and money to make a custom billing engine. They pay a fair price for not having to worry about anything.
Scenario B: The IoT Provider for Businesses

Profile: Selling smart sensors to factories. $30 million in sales each year. Pricing includes the cost of the hardware, a monthly platform fee, and a variable usage fee that depends on how much data is sent. There are also discounts for large orders and contracts that last more than one year.
Decision: BUILD (or Hybrid).
The reason is that no ready-made software can handle that exact combination of hardware, software, and usage billing well. They probably already have a group of developers. A custom solution lets them automate their complicated billing, which cuts down on the work their finance team has to do by hand.
The Secret Complications of Billing
It’s easy to not realise how much a billing system really does. It’s not just sending a bill.

What happens to dunning management when a credit card fails? A good system will automatically try again on smart schedules.
Proration: How do you figure out the bill if a customer upgrades on the 15th of the month?
In the US, ASC 606 standards tell you how to recognise revenue. For accounting purposes, your software needs to be able to do this.
Customer Portal: Customers need a place to change their cards and get copies of old invoices.
You have to build all of this if you build. It comes in the box if you buy it. This list of features is often what makes companies want to buy again. But with MyFluiditi’s development knowledge, we can add pre-built modules for these standard features. This lets you focus on custom development only on the unique pricing logic that makes you stand out.

Using AI to Help You Make Decisions
With the rise of advanced AI, the discussion about whether to build or buy billing software has changed.

You can only use the AI features that come with a legacy billing platform if you buy one. They could just add a simple “fraud detection” bot and be done with it.

When you work with a partner like MyFluiditi, AI can become a part of your financial operations:

Churn Prediction: Look at billing patterns to find customers who are likely to cancel before they do.
Dynamic Pricing: Change your pricing models in real time based on demand or different types of customers.
Automated Reconciliation: Use AI to match payments to invoices with almost perfect accuracy, which will save your accountants a lot of time.
AI changes billing from a behind-the-scenes job to a key driver of growth.

Ten Questions to Ask Yourself Before You Decide
Before you hire a developer or sign a contract, get everyone involved and answer these questions:

Is our pricing model set in stone, or do we plan to change it often?
Do we have engineers on staff who can help with a custom build?
How much money do we have to spend on operating expenses and capital expenses over the next three years?
How hard is it for us to connect to existing CRM and ERP tools?
Do we have specific security or data residency needs?
Are we losing customers because our current billing system isn’t flexible?
How much are we currently paying in transaction fees?
Do we do business in more than one currency or tax area?
Is billing one of our business’s main skills?
Is the choice between making or buying billing software slowing down our growth?
Making financial models for the US market
It costs a lot to hire developers in the US. This is the main reason the needle is pointing to “buy.” The cost of capital is also important.

Companies prefer OpEx (monthly subscriptions) to CapEx (large upfront build costs) when interest rates are high. If money is cheap, it makes more sense to buy a custom asset.

Also, think about the “Software Tax.” In many US states, SaaS is subject to sales tax. You usually don’t have to pay taxes on the use of software you make yourself. These tax breaks can add up over time and help the ROI of a custom build.

The MyFluiditi Benefit
We don’t just write code at MyFluiditi; we also design business solutions. We help clients find their way through the complicated process of building or buying billing software by giving them a third choice: Custom Development with AI Acceleration.

We can make a billing system that fits your business model perfectly, but we do it faster and more reliably than regular dev shops because we use AI to write code, test it, and scan it for security.

You own the software because you got the asset.
You get the fit: it works just like your business does.
You get the speed: We set up faster than other custom builds.
Making Your Choice Future-Proof
Things change quickly in technology. The billing system you pick today needs to still work in five years.

If you buy, you have to trust that the seller will keep coming up with new ideas. If they get bought or development slows down, you’re stuck on a sinking ship.
If you build something, you have to promise to keep making it better. You can’t just build it and forget about it. You need a plan.

A lot of US businesses are very worried about the risk of vendor lock-in. We’ve seen businesses have to move their data in a hurry because their billing provider raised prices by 300%. If you own your code, you can’t be a victim of this kind of corporate blackmail.

Conclusion: Choosing the Right Path
There isn’t just one right answer. There is only one right answer for your financial situation.

Choose to BUY if you are a startup in its early stages, your prices are simple, speed is your top priority, and you don’t have a lot of engineering resources.
Choose to BUILD if: you are a growing business, your fees are too high because of the number of transactions you make, your pricing logic is complicated, and you see technology as a way to get ahead of your competitors.
In the end, whether you build or buy billing software will be a big step in the right direction for your business. It makes you figure out what kind of business you are. Are you okay with fitting into someone else’s box, or do you need to make your own?

We at MyFluiditi are ready to help you figure out the numbers, and if the answer is “build,” we can help you do it. Your billing system is what makes your money. Don’t buy an engine that doesn’t fit your car.

Deep Dive: The Technical Truth About Building
To fully understand the financial impact of this choice, we need to look deeper into what “building” really means in 2024 and beyond. It’s not just writing code; it’s putting together a complicated ecosystem.

The Payment Gateway Layer
You’re not becoming a bank when you build. You will still use a payment gateway, such as Stripe, Braintree, or Adyen. These services take care of processing credit cards and making sure that the vaulting of card data meets PCI standards.

On top of this is your custom software. It tells the gateway to “Charge Customer A $50.” The gateway replies, “Success.” Your software then records that, updates the user’s access level, sends an email, and syncs with your accounting ledger.

The financial effect is that even if you build, you will still have to pay transaction fees to the gateway, which are usually around 2.9% plus 30 cents. But you don’t have to pay the extra fee that billing platforms usually add on top of this. This margin, which is usually between 0.5% and 1%, is where the savings come from.

The Notification System
Billing is a way to talk.

“Your bill is ready.”
“Your payment didn’t go through.”
“Your card is about to expire.”
It’s not easy to set up a reliable email and SMS notification system. Emails go to spam, and SMS messages get blocked. When you think about whether to build or buy billing software, keep in mind that “buying” usually comes with a pre-configured email service that works well. If you build, you have to connect with a service like SendGrid or Twilio and take care of your own sender reputation. Your churn rate goes up if your “Payment Failed” emails end up in spam. That is a financial risk of building that people don’t see.

The Engine for Reporting
Dashboards are where CFOs spend most of their time. They need to be able to quickly see Monthly Recurring Revenue (MRR), Churn Rate, Lifetime Value (LTV), and Average Revenue Per User (ARPU).

Most SaaS billing tools come with great, ready-to-use analytics.
When you build, you start with a blank screen. You have to ask your database questions and see the data for yourself.

The Cost: It can take weeks of frontend development to make a custom reporting dashboard.
The good thing is that you can measure exactly what you care about. Tools that come with your computer often calculate churn in ways that aren’t specific to your business. You can trust custom reporting to give you the “source of truth.”
What APIs and Microservices Do
Most of the time, modern custom billing software isn’t a single piece of software. Most of the time, it’s a group of microservices.

You could have:

A subscription service that keeps track of plans and cycles.
A Metering Service keeps track of how much you use (in gigabytes, hours, and seats).
An invoicing service makes PDFs.
This modularity is great for keeping things stable. People can still pay you even if the PDF generator crashes. But it makes things more complicated. DevOps engineers who are good at coordinating these services are needed. This adds to the ongoing cost of personnel for the “build” option.

We use containerisation tools like Docker and Kubernetes at MyFluiditi to handle this complexity in a way that keeps cloud costs low so you don’t have to pay for unused server space.

Currency and Global Expansion
The US market is big, but a lot of US companies sell their goods and services around the world.

Buying: Many platforms come with multi-currency support built in. They take care of the conversion and, in some cases, even the transfers to local banks.
Building: It’s a pain to deal with more than one currency. You need to keep track of exchange rates, record gains and losses from currency fluctuations in your ledger, and show prices in local formats.
If your plan calls for aggressive international growth in the next 12 months, the case for building or buying billing software often leans toward buying, just to make cross-border business easier. Unless, of course, you work with a development company that already has modules for internationalisation.

The elephant in the room is migration.
What if you buy now and build later? A lot of people use this strategy. But be careful about the cost of moving.

The most stressful thing a CTO can do is move billing data. You need to move credit card tokens (which requires payment gateways to work together), customer records, and past subscription data without stopping service or charging people twice by mistake.

If you know you’ll need a custom solution in the future, starting with a “Buy” solution will cost you money in the long run. You’re putting off doing it. Sometimes, it’s cheaper to build early and pay the price than to move two years later, which costs a lot of money.

Security: The Biggest Financial Risk
We can’t talk about money without also talking about risk. A data breach can put a company out of business.

You trust the vendor’s security when you buy. It’s their fault if they get hacked, but your reputation suffers.
You are the fortress in the building. You are in charge of the walls.
For some fields, like healthcare, defence, and finance, “buying” is hard because of strict rules about data privacy. It might not be okay to keep customer data on a SaaS platform that is shared by more than one tenant. In these situations, the only legal option is to build something or buy an on-premise solution.

MyFluiditi puts security first when it comes to development. We use encryption both when data is at rest and when it is being sent, strict role-based access control, and automated vulnerability scanning to make sure that your custom billing solution is as safe or safer than ready-made ones.

The Decision’s Effect on Culture
Lastly, think about the culture of your business.
Building gives your team more power. You say, “We can solve our own problems.” This creates a culture that puts engineering first.
If you buy, you help create a culture that is practical and values speed.

There is nothing wrong with either. But there is friction when a company with a “engineering-first” culture has to use rigid tools or when a “sales-first” culture has to wait for internal developers to fix bugs. The choice between building or buying billing software must fit with the company’s culture.

Summary Checklist: The Financial Scorecard

To wrap up, let’s create a scorecard to help you visualize the decision.

Final Thoughts from MyFluiditi

The world of billing is changing. We are blowing up monolithic ERPs in favor of agile, AI-driven financial stacks.

U.S. Companies are facing (stressed!) margins. Every percentage point counts. Although purchasing software makes a smooth and easy entrance, it can quickly turn into a tax on your way to growing up. Construction provides a road to sovereignty and fatter margins – as long as you have the right partner to guide you around the technical hurdles.

Whether or not a company should build vs. buy billing software isn’t simply a question of how to spend today’s budget. It is about tomorrow’s valuation. This is about whether you want to rent your financial infrastructure or own it.

At MyFluiditi, we’re all about taking responsibility. We’re of the opinion that the age of AI has now made custom software accessible to us all. Now, you can afford to create the perfect tool for your business.

Don’t let your billing software determine your business model. Your software should follow your business value model. If you’re interested in seeing what a customized AI-powered billing solution could do for your business, then contact us. Let’s make something that financially would have made sense.

Appendix: Common Billing Models and Their Fit

To further assist in your decision on building or buying billing software, it helps to identify where your specific billing model fits.

1. Flat Rate Subscription

• Example: $10/month for access.
• Recommendation: Buy. This is the “Hello World” of billing. Every tool supports it.

2. Per-Seat Pricing

• Example: $50/user/month.
• Recommendation: Buy. Standard feature in almost all SaaS billing platforms.

3. Usage-Based (Metered) Billing

• Example: $0.05 per GB of storage used.
• Recommendation: Hybrid/Build. While some vendors support this, it requires sending them constant usage events. If your metering logic is complex (e.g., tiers reset daily, or usage credits expire), custom logic is often required to aggregate the data before sending it to a billing engine.

4. Tiered Pricing with Overage

• Example: Includes 1000 API calls, then $0.01 per call.
• Recommendation: Buy. Most sophisticated vendors handle this well.

5. Dynamic/Algo-Pricing

• Example: Price changes based on real-time supply and demand (like Uber surge pricing).
• Recommendation: BUILD. No standard billing platform handles real-time algorithmic pricing effectively. You need a custom engine to calculate the price at the moment of transaction. This is a prime use case for MyFluiditi’s AI solutions.

6. Milestone Billing

• Example: 30% upfront, 30% on beta launch, 40% on completion.
• Recommendation: Build/Manual. This is typical for service agencies. Most recurring billing software hates this model. It’s often better to use simple invoicing software or build a custom project-tracking tool that triggers invoices.

7. Marketplace (Platform) Billing

• Example: You take a cut of transactions between two other parties (like Airbnb).
• Recommendation: Buy (Specialized). Use Stripe Connect or similar platform-specific tools. Building a marketplace ledger from scratch is incredibly difficult due to “know your customer” (KYC) laws and payout logic.

Understanding these nuances is key. You might think you just need “billing software,” but if you actually need “multi-party marketplace payout logic with dynamic commission rates,” you have already disqualified 99% of the “Buy” options.

The decision always comes back to the details. The devil-and the profit-is in the details. When you weigh building or buying billing software, ensure you have mapped out every edge case of your pricing strategy. Only then can you make the choice that secures your financial future.