Open-Source or Commercial AppSec Tools: Total Cost of Ownership Comparison

Open-source tools are not free. You save on licences, but you pay with engineers’ time for deployment, rule configuration, noise triage and maintenance. For small teams and first steps in AppSec they are often the best option. For large organisations with audits, dozens of teams and a need for support, a commercial solution or a hybrid is usually more cost-effective. The right question is not “what is cheaper”, but “what is the total cost of ownership (TCO) over three years”.

What makes up the TCO of an AppSec tool

Total cost of ownership includes much more than a line in a commercial offer. For both options, count:

• Licences and subscriptions: for commercial products, per developer, project, volume of code or server; for open source, zero, although paid enterprise editions are possible.
• Infrastructure: scanning servers, databases, storage, backup, network.
• Implementation: installation, integration with Git, CI/CD and the issue tracker, policy configuration.
• Maintenance: updates, migrations, monitoring, updating vulnerability databases and rules.
• Triage of findings: the time AppSec engineers and developers spend on triage and fixes, including false positives.
• Training: for developers and the security team.
• Cost of downtime and risk: what happens if the tool is unsupported or a key maintainer leaves.

Where open source is enough

Open-source solutions work well in several scenarios:

• Starting out and testing a hypothesis. You can get first results within days and show management the value of the process.
• Dependency tracking and SBOMs. OWASP Dependency-Track is distributed under Apache-2.0, works with SBOMs in the CycloneDX format, uses several vulnerability data sources (NVD, GitHub Advisories, OSV and others), and lets you configure policies that stop builds.
• Checking your own coding conventions. The Semgrep engine is distributed under LGPL-2.1, and its rules are written declaratively, which is convenient for enforcing internal code patterns.
• Specialised tasks. For example, secret scanning or IaC checks.
• A strong internal team. If you have engineers ready to develop and maintain the tool.

Hidden limitations of open source

• Depth of analysis. According to the Semgrep documentation, Community Edition analyses code only within a function or file. Cross-file analysis, which yields fewer false and more true positives, belongs to the paid Semgrep Code. The project repository warns that CE suits places where false positives are acceptable, and that it may miss many true positives.
• Maintenance is on you. Dependency-Track version 5 works only with PostgreSQL, and moving from 4.x requires a migration rather than an in-place update. Your engineers do this work.
• No contractual support. For regulated industries this is often an important argument: you need a responsible vendor and agreed response times.
• Fragmentation. Separate tools for SAST, SCA, secrets and IaC have to be tied together with unified reporting and policy.
• Supply chain protection. Tracking known vulnerabilities is not the same as blocking malicious packages at the entrance to the repository.

Where a commercial solution pays off

• Scale. With many teams, languages and repositories, a single platform with centralised policies wins. For example, Sonatype Lifecycle offers 18 default policies and more than 30 configurable conditions, SBOM generation and import, and reachability analysis for prioritisation.
• Audit requirements and reporting. Ready-made reports against standards (commercial SAST descriptions mention OWASP, PCI DSS and NIST 800-53) save time when preparing for audits.
• Closed environment. Vendor-supported installation and updates in an isolated network. Sonatype Firewall claims to work in an air-gapped environment.
• Noise reduction. Vulnerability confirmation and deep analysis reduce the time developers spend on false findings.
• Support and updates. A guaranteed channel, vendor responsibility, and regular updates of databases and rules.

How to calculate it: a simple three-year model

Take two columns and fill them in with your own numbers:

1. Open source: engineer hours for implementation + hours per month for maintenance + hours for extra noise triage + infrastructure. Multiply by the fully loaded hourly cost of your engineer (including taxes and overheads).
2. Commercial: three-year licence + infrastructure + implementation hours (usually fewer) + maintenance hours (usually fewer) + training.
3. Compare the totals and add the intangible factors: support SLA, audit requirements, and the risk of depending on a single employee.

Commercial prices depend on the number of developers, projects and modules. Most enterprise vendors have no public price list, so request a quote from the supplier. For Snyk the vendor publishes its plans, including a free one, but terms change, so check the current data on its website. We will cover budgeting for the whole DevSecOps process in separate materials; for first steps, read “DevSecOps: Where to Start”.

Hybrid strategy

The most common and practical approach is to combine them:

• open-source tools for dependency tracking, secrets and simple rules in development teams;
• commercial SAST and SCA for critical systems, where analysis depth, reporting and support matter;
• a unified process and a single vulnerability register across the whole set, so developers see one queue of tasks.

This way you do not pay for commercial licences where open source is sufficient, and you do not take risks where the cost of an error is high. To compare specific products, see the SAST comparison and the SCA comparison.

Questions to answer before deciding

• Who will maintain the tool a year from now, and what happens if that person leaves?
• Does your regulator or auditor require contractual support and documented processes?
• How many false positives are we prepared to triage by hand, and who will do it?
• Is work in a closed network required?
• How will the tool scale to all teams, not just the pilot project?

Example calculation for a team of 50 developers

Consider a hypothetical example without reference to vendor prices. An organisation with 50 developers wants to introduce SAST and SCA. The open-source option requires an engineer for implementation (several weeks), and then a share of an engineer’s time for maintenance, updates, rule configuration and triage. The commercial option adds licence fees but shortens implementation and triage time, and vendor support takes over part of the work. Which option is cheaper depends on the hourly cost of your engineers, the volume of code and the share of false positives. That is why an honest answer can only be obtained from your own data.

A rule of thumb to start with: if the organisation has fewer than two or three application security specialists, the cost of maintaining a set of open tools yourself quickly exceeds the savings on licences. If there is a strong platform team and the tool is needed for a narrow task, an open solution is a reasonable choice.

Finally, the decision does not have to be permanent. Plan a review in 12–18 months. By then it will be clear how much is actually spent on maintaining open tools, whether the share of false positives has grown, and whether auditors’ requirements have changed. If the cost of supporting a self-built stack grows faster than expected, that is a signal to move critical systems to a commercial platform while keeping open tools where they perform well.

Also consider the maturity of your processes. Even the best commercial product brings no value if nobody triages the findings and there is no agreement with developers on fix deadlines. That is why part of the budget should go to process and training, not only to licences.

Frequently asked questions

Sources

• OWASP Dependency-Track
• Dependency-Track on GitHub (Apache-2.0 licence)
• Semgrep on GitHub (LGPL-2.1 licence)
• Semgrep Docs: Semgrep Code vs Community Edition
• Sonatype Lifecycle: product page
• Sonatype Firewall: product page