SBOM: Definition, Components, Formats, Best Practices & Challenges

If you build or buy software today, you need to know exactly what’s inside it—and that’s where a software bill of materials, or SBOM, comes in. This article explains what an SBOM is, what it contains, and why organizations rely on it for visibility, risk reduction, and software supply chain security. We’ll walk through the main SBOM formats and standards, how to generate and automate SBOMs in real workflows, who should own them across the lifecycle, and the practical challenges you need to plan for.

What is a SBOM?

SBOM full form is Software Bill of Materials. SBOM is a structured, machine-readable list of ingredients that describes every software component inside a software product or software application, including both open source and proprietary software packages. For each component, an SBOM typically records attributes such as name, version, supplier, and how it relates to other components in the broader software ecosystem.

In modern software development, SBOMs give organizations and software vendors precise visibility into what their code is built from, so they know exactly which components are present when a new vulnerability or set of known vulnerabilities is disclosed. This makes SBOMs a foundational control for software supply chain transparency and software supply chain security, and a core input to broader cybersecurity and risk-management programs.

The US National Telecommunications and Information Administration formally described the SBOM as a baseline “list of ingredients” for software, and this definition underpins how sbom generation practices and SBOMs (plural sboms) are now being adopted across industries to track component inventory over the full lifecycle of critical software bills.

What does a SBOM contain?

A software bill of materials contains structured SBOM data that describes the ingredients that make up a software product, giving software component transparency across the software supply chain.

• Inventory of software components
  An SBOM lists all software components used in a software product or modern software applications, including open source software, third-party software, and commercial software from commercial software vendors, as a nested inventory of all software components.
• Identification, versions and dependencies
  For each component, an SBOM records clear software identification (name, supplier, unique identifier), exact software versions, and software dependencies (direct and transitive), so organizations can track and manage software as a software asset across the software supply chain.
• Licensing, security and risk fields
  An SBOM stores license information and security-related data that map components to known vulnerabilities and security risk, so SBOMs provide a foundation for vulnerability management, securing the software supply chain, and broader software supply chain risk management.
• Format, standards and generation metadata
  An SBOM also includes SBOM format or SBOM standards used, plus basic SBOM creation and SBOM implementation details (how and when the SBOM was generated, which SBOM tools or software composition analysis were used), supporting integrating SBOM generation into secure software development workflows.

What is an example of a software bill of materials in real projects?

A practical example of a software bill of materials is the SBOM for a single containerized microservice in a production e-commerce platform.

Imagine a checkout-service container image built from a Dockerfile. Its SBOM would be a machine-readable document (for example CycloneDX or SPDX) that lists every component that actually ships in that image, not just what’s mentioned in code comments. In one real project, that SBOM might include:

• Base image: gcr.io/distroless/base-debian11:nonroot  
• Runtime: python 3.11 plus core stdlib modules
• Frameworks: Django 5.0.x, Gunicorn 21.x
• Libraries: requests 2.32.x, cryptography 43.x, psycopg2 2.9.x
• OS packages: libssl, zlib, ca-certificates
• Metadata: supplier, license, hashes, and dependency relationships for each entry

At runtime, the container engine uses a container entrypoint (the command that launches the container’s main process, for example gunicorn checkout.wsgi) and Linux cgroups (which enforce resource isolation and limits for that process), but the SBOM is what tells you exactly which packages are inside the image when a new vulnerability is announced, so you can immediately check whether this specific checkout-service build is impacted.

What are the main SBOM formats and standards?

The main SBOM formats and standards are three mature, widely adopted schemas that describe the ingredients that make up software in a consistent, machine-readable way so security teams get visibility into the software supply and transparency into software across their estate.

• SPDX (Software Package Data Exchange)
  SPDX is a Linux Foundation standard used by software developers and vendors to represent a comprehensive inventory of software components and their licenses. In practice, SPDX describes each software artifact with identifiers, versions, relationships, and license data, so an SBOM provides a reliable basis for software asset management and license compliance. SPDX formats (tag-value, JSON, XML) are common when organizations want a single set of SBOM specifications to use across their software portfolios.
• CycloneDX
  CycloneDX, maintained by OWASP, is a security-focused SBOM format designed for software security and security and software supply chain use cases. It models components, services, dependencies within the software, and rich vulnerability, integrity, and cryptographic metadata. This makes it well suited when SBOM functions must directly support software supply chain security and ongoing security of the software supply. Many teams generate an SBOM in CycloneDX as part of CI/CD, then use it to track risks throughout the software supply chain.
• SWID tags (Software Identification Tags)
  SWID tags (ISO/IEC 19770-2) are standardized labels attached to installed software to support discovery and software asset management. While they are not full SBOMs by themselves, they can complement SBOM inventories by providing authoritative software identification at install time. In larger environments, SWID-based data and SBOM inventories together help sboms play a central role in tracking what components make up software components actually deployed in production.

On top of these formats, government-backed guidance such as the NTIA/CISA “minimum elements” and related SBOM resources define what a valid SBOM should contain, regardless of the specific SBOM format chosen.  

What are best practices for SBOM adoption?

Best practices for SBOM adoption focus on making SBOMs routine, accurate, and actionable across every software release, not just a compliance checkbox.

• Start with clear objectives and consistent formats
  Define why you need SBOMs (software transparency, compliance, or risk reduction) and standardize on one or two types of SBOM (for example SPDX for licensing, CycloneDX for security). This makes understanding SBOM structure easier for engineering and security teams.
• Integrate SBOM generation into the build pipeline
  Automate SBOM generation within CI/CD so every major software release produces an SBOM by default. Treat the SBOM as build output alongside artifacts and test reports, not as a separate manual export.
• Treat the SBOM as a nested inventory, not a flat list
  Ensure the SBOM is a nested inventory that maps direct and transitive dependencies, showing how components relate within the software. This structure should reflect the actual list of ingredients that make up each service or application.
• Enforce minimum data quality and coverage
  Set baseline fields (name, version, supplier, relationship) as required for every component. Make completeness and correctness part of your practices for software quality, with build checks that fail on missing or inconsistent SBOM data.
• Use SBOMs to frame software component transparency for security
  Wire SBOMs into vulnerability scanning, risk scoring, and exception handling so they actively support software supply chain security. Here, SBOMs should be the backbone for framing software component risk and framing software component transparency across microservices, libraries, and third-party packages.
• Prioritize critical and regulated systems first
  Roll out SBOMs first for high-impact applications (for example, customer-facing services, payments, or federal software subject to procurement rules), then expand coverage. This staged approach accelerates value while you refine internal standards.
• Centralize storage and access
  Store SBOMs in a searchable, versioned repository, linked to each artifact and environment. This allows teams to quickly answer “where is this vulnerable component used?” across the portfolio when software supply chain security continues to tighten.
• Train teams and define ownership
  Assign explicit ownership: engineering for creation, security for analysis, and platform/DevOps for pipeline integration. Provide concise training so teams share a common understanding SBOM and do not treat it as a one-off compliance document.

Applied consistently, these practices turn SBOMs from static files into living operational assets that deliver real software transparency and strengthen security across each software release.

What are the key challenges and limitations of SBOMs today?

Here are the key challenges and limitations of SBOMs:

• Many SBOMs are incomplete or inaccurate, missing transitive dependencies or mislabeling components, which limits trust in the inventory even when a container image, a packaged read-only bundle of an application and its dependencies, or binary looks fully scanned.
• SBOMs can go stale quickly because components and images are rebuilt, patched, and redeployed faster than SBOMs are regenerated, so the SBOM often lags behind what is actually running in production.
• Tooling and formats are fragmented, with different teams and vendors using different SBOM generators and schemas, which makes it hard to merge, compare, or query SBOMs across the organization.
• SBOMs can be noisy and hard to act on at scale, producing very large documents that list thousands of components without clear prioritization, so security teams still struggle to decide what to fix first.
• In container - heavy environments, SBOMs for each container image may not include full details for base images or sidecar containers, which leaves unseen gaps in the real dependency graph.
• Integrating SBOMs into existing vulnerability management, asset management, and CI/CD workflows is non-trivial, so many organizations generate SBOMs but do not yet operationalize them as a day-to-day security control.
• Legal, IP, and privacy concerns can limit how much SBOM detail vendors are willing to share externally, which reduces the usefulness of SBOMs for customers who want deep insight into third-party software.

Why do organizations need a SBOM?

A software bill of materials gives organizations a complete, verifiable inventory of every component inside a software product, so they always know exactly which libraries, frameworks, and dependencies they are running. It lets security teams quickly map new vulnerabilities to affected systems, answering with certainty “Are we exposed?” and “Where?”, which shortens remediation time and reduces the window of attack.

• When containers are scheduled via container orchestration, which automates deploying and scaling workloads across multiple machines, and executed by a container runtime, the low-level engine that starts and manages container processes on each node, SBOMs provide the only scalable way to track which vulnerable components are spread across clusters and must be rebuilt or replaced.
• When containers are scheduled via container orchestration and executed by a container runtime across many nodes, SBOMs provide the only scalable way to track which vulnerable components are spread across clusters and must be rebuilt or replaced.
• SBOMs create software transparency for regulators, customers, and partners, demonstrating that the organization can prove what code it ships and how it manages security risk over time.
• They support better internal governance by linking components to owners, systems, and environments, so engineering and security can coordinate patches and upgrades based on business impact rather than guesswork.

How do you generate, maintain and automate software bills of materials?

You generate, maintain, and automate software bills of materials by embedding SBOM creation directly into your build and release workflows rather than treating it as a one-off scan.

To Generate:

At build time, use SBOM-capable tools to scan source code, dependency manifests, and package managers for each software project and container image. For containerized workloads, integrate these tools into the image build so every Dockerfile produces a corresponding SBOM for the resulting image, tied to the exact image digest. When you push images to a container registry, a system that stores and distributes versioned container images, push the SBOM as an attached artifact so anyone pulling the image can also retrieve the SBOM for analysis.

To Maintain:

To maintain SBOMs, store them in an artifact or document repository indexed by version, commit, and image digest, and regenerate them whenever you rebuild or patch components instead of editing old files.

To Automate:

Automation comes from wiring SBOM generation into CI/CD: make SBOM creation a mandatory stage on every software release, fail the pipeline if SBOM generation or upload fails, and feed the resulting SBOMs into vulnerability scanners and policy engines. When a new critical flaw appears, you can query SBOMs to pinpoint affected components and trigger targeted rebuilds, turning SBOMs into an operational control that strengthens overall supply chain security rather than static documentation.

Who should create, manage and use SBOMs across the software lifecycle?

• Software engineers – Choose components and ensure SBOM creation is enabled for each codebase they own.
• Build and DevOps teams – Automate SBOM generation in CI/CD so every build and release produces a consistent SBOM.
• Platform / infrastructure teams – Store, index, and link SBOMs to running services and deployed artifacts across environments.
• Application security (AppSec) teams – Use SBOMs to map vulnerabilities to specific components and prioritize remediation.
• Security operations (SOC / IR) teams – Consult SBOMs during incidents to quickly find where vulnerable or compromised components run.
• Compliance, risk, and governance teams – Rely on SBOMs to evidence license compliance, policy adherence, and regulatory readiness.
• Procurement and vendor management – Request SBOMs from vendors and use them to assess third-party software supply chain risk.
• Software vendors and SaaS providers – Produce accurate SBOMs for their products and share them with customers as part of security assurance.
• Customer security and architecture teams – Ingest vendor SBOMs into internal tools to monitor, assess, and manage inherited component risk.

FAQs

Q1. What is a simple example of a software bill of materials in practice?

Ans: A1. A typical example is an SBOM for a single microservice (or container image) listing its base image, runtime, frameworks, libraries, and OS packages with names, versions, and suppliers.

Q2. How detailed should an SBOM be for a real-world project?

Ans: A2. At minimum, each component should include its name, version, supplier, and dependency relationships so you can reliably map new vulnerabilities back to specific builds.

Q3. Do small teams or startups really need SBOMs?

Ans: A3. Yes— even a small team running a few services benefits, because an SBOM lets them answer “where are we using this vulnrable library?” in minutes instead of days.

Q4. How often should SBOMs be updated in live projects?

Ans: A4. Generate a fresh SBOM for every release build or image rebuild so the SBOM always matches the exact artifact you deploy.

Q5. Should software vendors share SBOMs with their customers?

Ans: A5. Ideally yes—vendors should provide SBOMs for key products so customers can evaluate inherited risk and integrate those components into their own vulnerability management.