Build vs Buy Software: The 2025 Decision Framework

Your company is paying $4,200/month for SaaS subscriptions. Salesforce, HubSpot, Asana, Slack, Zoom, Zapier, Tableau, and 15 other tools.

That's $50,400 per year. And here's the frustrating part: none of them do exactly what you need.

Salesforce has 80% of the features you want, but you're paying for 200% of what you need. Your team spends hours every week working around limitations, exporting data to Excel, and using "creative workarounds" because the SaaS tool won't bend to your workflow.

So when does it make sense to stop paying for off-the-shelf software and build something custom?

In 2025, the answer has changed. AI-accelerated development has made custom software faster and cheaper than ever before. What used to cost $150k and take 9 months can now be built for $40k in 6 weeks (learn more about how we build software 10× faster).

Let's break down the build vs buy decision with a framework that actually works.

The Build vs Buy Question

Every business faces this decision multiple times:

• Should we use Salesforce or build a custom CRM?
• Should we use Zapier or build custom automation?
• Should we use Tableau or build a custom dashboard?
• Should we use an off-the-shelf marketplace platform or build our own?

The traditional advice was: "Always buy. Custom development is too expensive and too slow."

That was true in 2015. It's not true in 2025.

When to Buy (Off-the-Shelf SaaS)

Start here: default to buying unless you have a compelling reason to build.

Buy When the Tool Is a Commodity

Some software categories are mature, well-understood, and commoditized. Everyone needs them, they all work roughly the same way, and there's no competitive advantage in building your own.

Examples of commodities — always buy:

• Email: Google Workspace, Microsoft 365 (don't build your own email system)
• Payments: Stripe, PayPal (don't build your own payment processor)
• Authentication: Auth0, Okta (don't build your own auth from scratch)
• Cloud Infrastructure: AWS, Google Cloud, Azure (don't build your own data centers)
• Communication: Slack, Zoom, Teams (don't build your own chat or video tool)

Buy When It's Not Your Core Competency

If the software supports your business but isn't central to your competitive advantage, buy it.

Example: You're a fintech startup. Your core competency is financial algorithms and compliance. Your internal HR system? That's not your differentiator. Buy BambooHR or Rippling.

Buy When Time-to-Value Is Critical

If you need a solution live today, buy it. Don't wait 6 weeks to build custom (though with AI-accelerated development, 6 weeks is often possible).

Example: You need CRM functionality immediately to manage your sales pipeline. Buy Salesforce now, iterate on custom later if needed.

Buy When Your Needs Are Standard

If your workflow matches 90% of what the SaaS tool offers, buy it. The 10% gap probably isn't worth custom development.

Example: You need project management. Asana, Monday.com, or Jira will get you 90% of the way there. Build custom only if your process is truly unique.

When to Build (Custom Software)

Now for the interesting part: when does custom development make sense?

Build When It's Your Core Competency

If software IS your product, you build it. Obvious, but worth stating.

Example: You're a SaaS startup. Your product is custom-built. That's the whole business model.

Build When It's a Competitive Advantage

If the software gives you an edge over competitors, build it. Don't give that advantage to an off-the-shelf vendor who also sells to your competitors.

Example: Your logistics company has a unique routing algorithm that saves 20% on delivery costs. That's your competitive moat. Build it custom. Don't use generic routing software.

Build When You're Fighting the Tool

If your team spends 10+ hours per week working around limitations of your SaaS tool, it's time to evaluate custom.

Red flags that you're fighting the tool:

• Daily exports to Excel because the tool won't let you view data your way
• Paying for 50 seats but only using 20 because licensing forces you to
• Constant "creative workarounds" because the tool doesn't support your workflow
• Integrations break weekly and require manual fixes
• Your team has to change their process to fit the software (instead of software fitting the process)

Build When Long-Term Cost Favors Custom

Sometimes the math is simple: building custom is cheaper over 3-5 years than paying SaaS subscriptions.

Example: You're paying $600/month for Zapier because you have 40 complex workflows. That's $7,200/year or $36,000 over 5 years. A custom automation system costs $25k to build and $2k/year to maintain. You break even in Year 2 and save $15k by Year 5 (see our guide on when to graduate from Zapier).

Build When You Need Deep Integration

If you need software that tightly integrates with 5+ other systems and those integrations are mission-critical, custom often wins.

Example: You need a dashboard pulling real-time data from Salesforce, NetSuite, Google Analytics, your custom database, and an internal API. Off-the-shelf BI tools can do this, but the integrations are brittle and break often. A custom dashboard built exactly for your data sources is more reliable (see custom executive dashboards).

Build When Your Workflow Is Truly Unique

If your process doesn't match any SaaS tool because your business model is novel, custom is the only option.

Example: You run a marketplace with a unique 3-sided model (buyers, sellers, and intermediaries). Off-the-shelf marketplace platforms assume 2-sided markets. You need custom.

The 2025 Game-Changer: AI-Accelerated Custom Development

Here's what's changed since the traditional "always buy" advice:

Then (2015):

• Custom software: $150k, 9 months
• SaaS tool: $500/month, live today
• Decision: Buy unless you have $150k and 9 months to spare

Now (2025 with AI-accelerated development):

• Custom software: $30k, 6 weeks
• SaaS tool: $500/month ($6k/year, $30k over 5 years)
• Decision: Build vs buy is now competitive on both cost and timeline

AI-accelerated engineering has collapsed the time and cost of custom development (see the Ironmind process). What used to take 6 months now takes 6 weeks. What used to cost $150k now costs $35k.

This changes the build vs buy calculus.

Build vs Buy: Decision Framework

Use this framework to decide:

Step 1: Is It a Commodity?

Yes → Buy (email, payments, auth, infrastructure)
No → Continue to Step 2

Step 2: Is It Core to Your Competitive Advantage?

Yes → Build (this is your moat)
No → Continue to Step 3

Step 3: Does an Off-the-Shelf Tool Fit 90% of Your Needs?

Yes → Buy (the 10% gap isn't worth building custom)
No → Continue to Step 4

Step 4: Run the 5-Year Cost Analysis

• SaaS cost: Monthly subscription × 60 months
• Custom cost: Upfront build + annual maintenance × 5 years

If custom is cheaper over 5 years → Build
If SaaS is cheaper → Continue to Step 5

Step 5: How Much Time Does Your Team Spend Fighting the Tool?

• Less than 5 hours/week: Buy (tolerable friction)
• 5-10 hours/week: Consider building (opportunity cost is real)
• More than 10 hours/week: Build (the tool is a net negative)

Build vs Buy Comparison Table

Factor	Buy (SaaS)	Build (Custom)
Time to Launch	Immediate (hours)	4-8 weeks (with AI-accelerated dev)
Upfront Cost	Low ($0-$500 to start)	Medium ($20k-$60k)
Ongoing Cost	High (monthly subscription forever)	Low (maintenance only, $2k-$5k/year)
5-Year Total Cost	$30k-$100k+ (depends on scale)	$30k-$80k (upfront + maintenance)
Customization	Limited (what the vendor allows)	Unlimited (you own it)
Workflow Fit	80% fit (you adapt to the tool)	100% fit (tool adapts to you)
Integration	Pre-built integrations (limited)	Custom integrations (unlimited)
Vendor Lock-In	High (hard to migrate)	None (you own the code)
Competitive Advantage	None (competitors use same tool)	High (unique to your business)
Maintenance	Vendor handles (you have no control)	You handle (but you have control)

Real-World Examples: Buy vs Build

Example 1: CRM for Sales Team

Scenario: 10-person sales team, standard B2B sales process

Decision: Buy Salesforce or HubSpot
Why: Standard sales process, off-the-shelf tools fit 95% of needs, not core competency

When to build instead: If your sales process is unique (e.g., multi-stage, multi-stakeholder enterprise deals with custom approval workflows that no CRM supports)

Example 2: Internal Operations Dashboard

Scenario: Executive team needs dashboard pulling data from Salesforce, NetSuite, Google Analytics, custom DB, internal API

Decision: Build custom dashboard
Why: Deep integration with 5+ systems, existing BI tools are brittle and require constant maintenance, custom dashboard costs $18k vs $800/month for Tableau ($48k over 5 years)

Example 3: Workflow Automation

Scenario: 15 automation workflows across marketing, sales, and ops

Decision: Start with Zapier, build custom when you outgrow it
Why: Zapier is fast to set up. When you hit 40+ zaps and $600/month, evaluate custom (see Zapier vs custom automation)

Example 4: Marketplace Platform

Scenario: Building a niche marketplace (buyers and sellers)

Decision: Start with Sharetribe or Bubble (no-code), migrate to custom if you gain traction
Why: Validate product-market fit fast. Once you have 1,000+ users and revenue, invest in custom for competitive differentiation (see no-code vs custom MVP)

The Hybrid Approach (Best of Both Worlds)

You don't have to choose 100% buy or 100% build. The smartest approach is often hybrid:

Buy Commodity, Build Unique

• Buy: Stripe (payments), Auth0 (authentication), AWS (infrastructure)
• Build: Your core product, unique workflows, competitive differentiators

Start with SaaS, Migrate to Custom Later

• Phase 1: Use Zapier, Salesforce, Airtable (validate fast)
• Phase 2: Once you hit scale or limitations, migrate to custom

Use SaaS as Proof of Concept

• Build a workflow in Zapier to prove it works
• If it delivers $30k/year in value, invest $20k to build it custom
• Now you own it, it's faster, and it costs less long-term

Common Mistakes to Avoid

Mistake 1: Building When You Should Buy

Example: Building your own authentication system instead of using Auth0
Why it's wrong: Auth is a commodity. It's been solved. You're not going to do it better than the experts.
Cost: Wasted $40k and 3 months building something you could have bought for $200/month

Mistake 2: Buying When You Should Build

Example: Paying $800/month for a BI tool that doesn't integrate well with your custom systems
Why it's wrong: You're paying $9,600/year for a tool that requires 10h/week of manual work to keep it updated
Cost: $9,600/year + 10h/week × $50/hour = $35,600/year vs $25k one-time custom build

Mistake 3: Assuming Custom Is Always Slow and Expensive

Reality in 2025: AI-accelerated development delivers custom software in 4-8 weeks for $20k-$60k. That changes the math.

The Bottom Line

The build vs buy decision isn't binary. Use this framework:

1. Always buy commodities (email, payments, auth, infrastructure)
2. Always build core competencies (your product, your competitive moat)
3. For everything else, run the math: 5-year cost, time spent fighting the tool, workflow fit
4. When in doubt, start with SaaS — then migrate to custom if you outgrow it

In 2025, custom software is faster and cheaper than ever. The question isn't "Can we afford to build?" It's "Can we afford NOT to build?"