A SaaS startup can build a useful supply chain security program in about a quarter by working in stages: inventory what you ship, lock and scan dependencies, protect the build, produce provenance, and keep a short vendor list. Pick the practices that fit a small team and skip the paperwork until a customer asks for it.
Which frameworks should guide you?
NIST SP 800-218, the Secure Software Development Framework, describes a core set of high-level secure development practices that can be added to any lifecycle model. NIST says it should help producers reduce vulnerabilities in released software, limit the impact of those not found, and address root causes, and that buyers can use its vocabulary in acquisition. For build integrity, SLSA offers levels. At Build L1, provenance exists showing how the package was built. L2 requires a hosted build platform, and L3 requires hardened builds. SLSA itself describes L1 as easy to bypass or forge, so treat it as a start.
Stage 1: know what you have (weeks 1 to 2)
List every repository, service, container image and third party service. For each deployable, generate a software bill of materials in CI and store it with the build. Constructed example: a five person team finds two forgotten services still deploying from a former employee's fork. The inventory is worth it for that alone.
Stage 2: control dependencies (weeks 2 to 4)
Commit lockfiles. Use a private proxy or registry setting that stops a package with an internal name from resolving to a public one. Scan dependencies in pull requests and fail the build on policy, such as known exploited vulnerabilities or a critical flaw in code that is actually reachable. Decide who triages and how fast.
Stage 3: protect the build (weeks 4 to 8)
The pipeline can publish anything, so treat it like production. Use short-lived credentials from your CI provider, not long-lived keys. Pin third party actions or plugins to immutable references. Require review on changes to pipeline files. Separate who can merge from who can deploy as soon as you have a second engineer.
Stage 4: provenance and signing (weeks 8 to 12)
Build on a hosted platform and record provenance for each release, which gets you to SLSA Build L2 territory. Sign artifacts and verify the signature at deploy. Keep the release records you would need to answer a customer asking, "which build did we get, and from what source?"
Stage 5: suppliers and incidents
Keep a one page vendor list: who they are, what data they touch, how you would learn of their breach, and how you would leave. Write a short runbook for a compromised dependency: how to find affected builds from the inventory, how to rotate secrets, how to tell customers.
How do you avoid over-building?
Skip anything that no one will use in the next two quarters. A signed attestation nobody verifies is cost without benefit. The inventory and the gate create most of the value early. Add the rest when a customer, an auditor or an incident asks.
What to do
- Generate and store an SBOM for every deployable.
- Commit lockfiles and block dependency confusion at the registry.
- Add a pull request gate with a written policy.
- Move CI to short-lived credentials and pin third party references.
- Record build provenance and verify it at deploy.
- Keep a vendor list and a compromised dependency runbook.
- Map your practices to SSDF groups so you can answer questionnaires from one page.
Safeguard covers several of these steps: SBOM and dependency scanning, reachability analysis, policy gates on pull requests, and a free in-browser scan at gold.safeguard.sh/scan for up to 100 dependencies. See /demos/gate-pull-request for how a gate looks.
Quick check
What is the smallest useful first step?
An inventory: an SBOM for each deployable stored with the build. Every later step depends on knowing what you ship.
Is SLSA Build L1 enough?
SLSA says L1 provenance can prevent mistakes but is trivial to bypass or forge. It is a starting point, not tamper protection.
Sources
Last reviewed: 18 October 2026.
