How to Find a SaaS Worth Building for B2B SaaS
Most B2B SaaS ideas fail the same test: they are solutions looking for problems. The founder builds what they imagine a business needs, rather than what businesses are already paying for in a worse form. Finding a B2B SaaS worth building starts with identifying pain that already has budget attached to it — pain that companies are already spending money to manage, even if the existing solution is inadequate.
🔍 Where B2B SaaS Opportunities Come From
The most reliable B2B SaaS opportunities share a common pattern: they replace a workflow that currently involves spreadsheets, manual processes, or stitched-together tools that were never designed to work together. These are gaps that existing software vendors have either ignored or addressed poorly.
Four sources worth systematically investigating:
- → Your own work experience: The workflow problems you encountered as an employee, consultant, or customer are problems you understand at depth. Domain expertise is a competitive advantage; building in an unfamiliar industry is a research tax you pay for years.
- → Competitor reviews: G2, Capterra, and Trustpilot 3-star reviews for established tools in a category tell you exactly what users hate. "It does everything except X" is a product brief. Read 50 reviews across 3–5 tools in a category and you will see the gaps that have not been addressed.
- → Job description patterns: When companies hire for a specific manual role at scale ("Excel analyst", "data coordinator", "pricing ops specialist"), that role is a software product waiting to be built. The job exists because there is no tool; the tool would replace the job.
- → Regulation and compliance changes: New regulations create compliance requirements that existing software does not handle. GDPR created a category of privacy management tools. Similar opportunities emerge with every regulatory shift in regulated industries.
📊 Market Sizing for B2B SaaS
B2B SaaS market sizing follows a different logic than consumer market sizing. The relevant question is not "how many companies exist" — it is "how many companies have the specific workflow problem and the budget to pay for software to fix it."
| Sizing Step | What to Calculate | Useful Data Source |
|---|---|---|
| Total addressable market | All companies with the problem, regardless of budget | LinkedIn company count by industry and size |
| Serviceable addressable market | Companies with budget and decision-making authority to buy | Filter by revenue range using Crunchbase or Apollo |
| Initial target segment | The subset you can reach and close in Year 1 | Your direct network + one go-to-market channel |
| ACV estimate | What one customer pays annually for a similar tool today | G2, Capterra pricing pages, competitor pricing tiers |
A B2B SaaS viable at seed stage needs a serviceable addressable market of at least 10,000 companies and an ACV of at least $1,200/year (to support any meaningful customer acquisition cost). Below these thresholds, the market is unlikely to support a venture-scale business — though it may support a profitable bootstrapped business with lower growth ambitions.
⚔️ Competitive Gap Analysis
Every B2B SaaS category has incumbents. The question is not whether competition exists — it is whether there is a gap that the incumbents have structurally chosen to ignore or cannot serve without rebuilding their core product.
Four gap types worth building toward:
- → Segment gap: The incumbent serves enterprise; SMB companies are underserved by a product built for a team of 100. Or the inverse: a tool built for SMB is not compliant or scalable enough for enterprise.
- → Integration gap: The incumbent has poor integrations with a category of tools that your target customer uses heavily. A CRM that does not integrate with the modern data stack is a CRM that data teams replace.
- → UX gap: The incumbent product is technically capable but requires training and a professional services engagement to use. A simpler interface for the same functionality wins on ease of evaluation and deployment.
- → Vertical gap: The incumbent is horizontal (serves any industry) and ignores industry-specific workflows. A vertical SaaS that deeply understands one industry's specific requirements can command higher prices and lower churn in that vertical.
What to Do Next
Pick one source from the "Where B2B SaaS Opportunities Come From" section and spend 5 hours on it this week. If you choose competitor reviews: read 50 reviews across the top 3 tools in a category you understand and write down every complaint that appears more than twice. If you choose your work experience: write down the 5 workflows at your last job that were either manual, or managed with tools that frustrated you. The opportunity is usually in that list — and your domain expertise is the advantage you will use to build and sell it.