Open source is not “free of legal process”
Modern product teams ship on top of hundreds of open source packages. That speed is normal. What is not normal is discovering a copyleft obligation two weeks before an enterprise security review, or realizing a mobile app embeds a library whose license requires source offers you never prepared. Open source license compliance is not anti-OSS ideology. It is inventory, policy, and boring hygiene so you can keep using the ecosystem without surprise obligations.
This checklist is educational for early product companies—seed to Series B style teams—shipping SaaS, mobile, or on-prem components. It is not legal advice, and licenses differ in nuance. When a deal, acquisition, or on-prem distribution is on the line, have counsel review your specific stack. The steps below are the work you should already have done before that call.
Compliance starts with a fact most founders skip: you cannot manage what you have not listed. “We mostly use MIT” is not an inventory. Transitive dependencies—libraries your libraries pull in—often dominate risk. A single GPL or AGPL package deep in the tree can matter more than the top-level frameworks you remember adding on day one.
Build an inventory before you write a policy
Generate a software bill of materials from your package managers and container images on a recurring cadence: every release candidate, or at least weekly on the main branch. Record package name, version, license SPDX identifier when available, and whether the component is modified. Store the SBOM where security and engineering leads can find it—not only on one laptop.
Classify licenses into working buckets your team understands: permissive (MIT, BSD, Apache 2.0 style), weak copyleft (often LGPL-class issues depending on linking), strong copyleft (GPL), network copyleft (AGPL and similar), and unknown or proprietary-in-disguise. Unknown is a red flag: quarantine until identified. Do not treat “GitHub says MIT in the README” as authoritative if the package metadata disagrees; reconcile conflicts deliberately.
- Automate scanning in CI so new dependencies cannot merge silently.
- Pin versions to make SBOMs reproducible; floating ranges create license drift.
- Track modifications: forked copyleft code usually raises the compliance bar.
- Include build tooling and SDKs you distribute to customers, not only server code.
Know when distribution and SaaS change the analysis
Many permissive licenses mainly require attribution and notice preservation. Copyleft licenses may require you to provide corresponding source and keep derivative works under the same terms when you distribute binaries. Shipping a mobile app, an installer, or an appliance is a classic distribution trigger. Pure server-side SaaS sometimes avoids GPL distribution triggers—yet AGPL-style licenses are specifically aimed at network use, and customer contracts may still demand disclosures regardless of a narrow reading.
If you offer on-prem, private cloud, or customer-managed agents, assume distribution analysis applies and involve counsel early. If you only run multi-tenant SaaS, still maintain notices for packages that require them, and watch AGPL, SSPL-like, and marketplace terms that constrain managed service use. Policy should state which license families are approved by default, which need legal review, and which are banned in shipped clients.
Attribution is the compliance task teams underestimate. Apache 2.0 and many permissive licenses expect NOTICE files and copyright lines to travel with distributions. Build a release step that assembles third-party notices automatically. Missing attribution is a frequent, fixable finding in buyer questionnaires—until it is not fixed and blocks a deal.
Vendor, AI-assisted code, and acquisition due diligence
Your vendors’ open source becomes your problem in diligence. Ask critical suppliers for their SBOM or license policy when they deliver embedded components. For AI coding assistants, set rules: no pasting proprietary code into tools that retain prompts if policy forbids it, and review surprising new dependencies the assistant adds. Treat “the model wrote it” as still your license obligation.
- Approved list: permissive licenses auto-OK with notice tooling.
- Review list: LGPL, GPL, AGPL, unknown—ticket before merge.
- Ship checklist: SBOM attached, NOTICE generated, copyleft decisions documented.
- Deal readiness: one owner can answer customer OSS questionnaires in forty-eight hours.
Make compliance a release habit, not a fire drill
Assign a clear owner—often security or a staff engineer with legal backup—not “everyone.” Review exceptions in a short monthly meeting. When you must use a risky license, document the isolation strategy (process boundary, dynamic linking approach counsel accepts, or replacement plan) and a removal date if the dependency is temporary.
Buyers, larger design partners, and acquirers increasingly expect OSS hygiene alongside SOC 2 narratives. Teams that can produce an SBOM, a license policy, and a notice file look adult. Teams that scramble through node_modules during a security questionnaire look unprepared. Open source remains a strategic advantage when you respect the licenses that made the commons possible. Inventory, classify, automate notices, and escalate copyleft decisions early—that is the compliance checklist early product teams can actually run.