Engineering overspend, measured from your git history

The cost nobody puts on a budget line

Every product company knows its headcount and its burn. Very few know how much of that money pays for the work itself and how much pays for the way the product is put together.

That second part is what The Engineering Tax series is about. A feature that should take a week takes two months, because three systems have to stay in sync. I call that the Sync Tax. The baseline is the Vacuum Effort: what the change would cost if nothing else had to change with it. On top of both sits the cost of what each change is likely to break.

None of this shows up in payroll. It hides in meetings, reviews, waiting and rework. So when the board asks for a cut, the cut lands on what is visible, which is people, and the expensive part stays.

The Engineering Cost Calculator puts a number on this from your own estimates. Defusor measures it from what actually happened in your repositories.

How it works

1. Get in. During the testing phase you start by requesting a free test on the Defusor site. Testers join through an invitation and skip the payment step.
2. Link GitHub, read-only. You install the Defusor GitHub App on all repositories. It can read contents, pull requests and issues. It cannot write anything.
3. Enter your company details. The company display name, the loaded hourly rate of one engineer (salary and overhead), and the currency for the report: USD, EUR or PLN.
4. Defusor picks the product. It decides which repositories belong to the product and treats each one as a component of it.
5. The analysis runs. AI agents read the git history and pull requests and find the patterns. Fixed formulas from The Engineering Tax turn those patterns into hours. Every dollar on the report is hours times the rate you entered.
6. The report arrives. You get a PDF by email for the last completed calendar quarter, and then one every quarter.

What you get

A quarterly PDF that covers only the work finished in that quarter. It says:

• What that work should have cost. This is the Vacuum Effort.
• How much extra you paid because of how the product is put together: parts that have to change together, waiting and review, and tangled upkeep. This is the sync tax.
• The expected cost of the breaks that this work is likely to cause.
• How each number was worked out.
• Where the extra is coming from.
• What to untangle first.

The five metrics behind it

• Vacuum Effort: what a change would have cost if nothing else had to change with it. Every other number is measured against it.
• Sync tax: the hours paid on top of that baseline because parts have to change together, wait on each other and be reviewed together.
• Domain coupling: how much a change in one area forces changes in others.
• Failure risk cost: the expected cost of the breaks the current structure invites.
• Incident cost: what production failures actually consumed.

Each one has its own help page on the Defusor site that explains what it means and how it is computed.

There is no dashboard. The app holds your report status, your company details and your subscription. The numbers live in the PDF.

Who it is for

CEOs and CTOs of Series B and Series C SaaS companies where engineering is a large share of spend and leadership cannot see where that spend goes. The CEO reads the report. The CTO or tech lead links GitHub and enters the hourly rate. There is one account per company.

Who it is not for

• Agencies and companies that do not build their own product.
• Teams whose code is not on GitHub. GitHub is the only source Defusor reads.
• Anyone who wants live engineering metrics. Defusor sends a quarterly report, not a dashboard.

Pricing

$59 per engineer per month, priced per git contributor rather than per seat. An engineer is anyone who committed to the product repositories in the latest month, contractors included. Billing is monthly and the report is quarterly. You can cancel at any time in the Stripe customer portal.

During the testing phase Defusor is free for a few Series B and C SaaS companies in exchange for feedback. Customer sign-up opens after the testing phase.

Your code and your data

• GitHub access is read-only.
• Git data is fetched only while an analysis runs. Defusor keeps the rows it extracts, such as commit metadata and pull requests, and does not keep your source files or a working copy.
• The service runs on Google Cloud in the EU.

The privacy policy on the Defusor site lists the services that handle your data and how long it is kept.

Frequently asked questions