Knowing what technologies a company uses—and who uses your competitors' products—gives you a real advantage. Sales teams can personalize outreach. Product teams can spot market trends. Marketers can target the right accounts.
But how do you actually find this information?
This guide covers nine practical methods, ranked from most manual to most automated. Each has trade-offs in terms of accuracy, coverage, and effort required.
Why This Matters
Understanding a company's tech stack helps with:
- Sales prospecting: Tailor your pitch to integrate with tools they already use
- Competitive intelligence: See who's using your competitors' products
- Partnership opportunities: Find companies using complementary technologies
- Market research: Spot adoption trends across industries
- Account-based marketing: Build targeted campaigns for specific technology users
The challenge? This information isn't always public. Let's look at what works.
1. Analyze Job Postings
Job descriptions reveal what tools companies actually use. When hiring developers or IT professionals, companies list specific technologies candidates need to know.
Manual Steps
- Search the company's careers page or job boards like LinkedIn Jobs, Indeed, or Glassdoor
- Focus on technical roles: software engineers, DevOps, data engineers, marketing ops
- Read the "Requirements" and "Tech Stack" sections carefully
- Note recurring technologies across multiple job posts
Tools
- TheirStack — aggregates job postings to extract tech stack data automatically
Example: A company hiring for a "Senior Backend Engineer" might list: "Experience with Python, Django, PostgreSQL, Redis, and AWS." That's five data points about their infrastructure.
Pros: Free, accurate (companies list what they actually use), reveals internal tools not visible externally
Cons: Time-consuming, limited to companies actively hiring, may show aspirational tech rather than current stack
2. Check Employee LinkedIn Profiles
Current employees often list the technologies they work with in their skills and experience sections. This reveals tools actually in use, not just hiring plans.
Manual Steps
- Search LinkedIn for employees at the target company
- Filter by technical roles: engineers, developers, DevOps, data scientists
- Look at their "Skills" section for specific technologies
- Read job descriptions in their "Experience" section
- Check multiple profiles to confirm patterns
Tools
Example: A data engineer's profile might list: "Skills: Snowflake, dbt, Airflow, Python, AWS Redshift." Their experience section might mention migrating from Redshift to Snowflake—showing both current and previous tech.
Pros: Shows what's actually in use (not aspirational), works even when companies aren't hiring, free to access
Cons: Time-consuming to check multiple profiles, employees may not keep profiles updated, some skills may be from previous jobs
3. Inspect Website Source Code
Many technologies leave fingerprints in a website's HTML, JavaScript, and HTTP headers. You can detect analytics tools, CMS platforms, frameworks, and more.
Manual Steps
- Right-click on the website and select "View Page Source"
- Look for script tags, meta tags, and comments that reference specific tools
- Check HTTP headers using browser dev tools (Network tab)
- Look for patterns in file paths and naming conventions
Tools
What you can find: Analytics (Google Analytics, Mixpanel), tag managers, A/B testing tools, live chat widgets, CMS platforms, JavaScript frameworks, CDNs, and hosting providers.
Pros: Quick for front-end technologies, free tools available
Cons: Only reveals client-side technologies, misses backend infrastructure, internal tools, and most B2B software
4. Check DNS and WHOIS Records
DNS records and WHOIS lookups reveal infrastructure details that aren't visible on a website's front end, including email providers, CDNs, and hosting.
Manual Steps
- Look up the domain's DNS records
- Check MX records to identify email providers (Google Workspace, Microsoft 365)
- Look at NS records to see DNS providers (Cloudflare, AWS Route 53)
- Examine TXT records for verification tokens from tools like Salesforce, HubSpot, Atlassian
Tools
Example: A TXT record containing google-site-verification confirms they use Google Search Console. A record with _spf.salesforce.com indicates Salesforce usage.
Pros: Reveals infrastructure and B2B tools not visible on websites, free to access
Cons: Requires some technical knowledge to interpret, doesn't show all software categories
5. Check Review Sites
Customers often mention the products they use on review platforms. This method helps you identify users of specific software products and get context on how they use them.
Manual Steps
- Search for the product you're researching on review sites
- Read reviews and note the reviewer's company and role
- Cross-reference reviewers on LinkedIn to verify and get contact details
- Look for patterns in company sizes and industries using the product
Tools
Example: Searching for Asana reviews on G2 shows hundreds of verified users with their company names and job titles.
Pros: Identifies actual customers with verified usage, includes context about how they use the product
Cons: Only 5-10% of users write reviews, so you're seeing a small sample. Time-consuming to compile.
6. Browse StackShare
StackShare is a community where companies voluntarily share their tech stacks. The platform has data on over 1.5 million companies using 7,000+ technologies.
Manual Steps
- Search for the company on StackShare
- View their publicly shared stack (if available)
- See which tools they've endorsed or discussed
- Browse stacks of similar companies for patterns
Tools
Example: Many well-known startups like Airbnb, Uber, and Slack have detailed public stacks showing everything from their database to their monitoring tools.
Pros: Self-reported data is often accurate for internal tools (Slack, Notion, databases) that aren't visible externally. Includes context on why companies chose specific tools.
Cons: Only works for companies that have created profiles. Stacks may be outdated if not actively maintained.
7. Find Subprocessor and Vendor Lists
Companies publish lists of their technology vendors for GDPR, SOC 2, and other compliance requirements. These lists reveal B2B software usage that's otherwise hidden.
Manual Steps
- Search for "[Company Name] subprocessors" or "[Company Name] third-party vendors"
- Check their Trust Center, Security page, or legal/privacy section
- Look for GDPR documentation—it often includes a complete vendor list
- Review their SOC 2 reports if publicly available
Tools
- Google Search
- Company Trust Centers
Example: A company's subprocessor list might reveal they use Stripe (payments), Snowflake (data warehouse), Zendesk (support), and AWS (hosting)—information you'd never find from their website.
Pros: Highly accurate (legally required to be correct), reveals B2B tools and infrastructure, free to access
Cons: Not all companies publish these lists publicly. May not include every tool they use.
8. Monitor Public Infrastructure
Companies expose parts of their tech stack through APIs, open-source contributions, and developer documentation.
Manual Steps
- Check their GitHub or GitLab for open-source projects
- Review their API documentation for technology hints
- Look at their developer blog or engineering posts
- Monitor press releases and partnership announcements
Tools
Pros: Reveals backend technologies and engineering culture, often includes detailed technical decisions
Cons: Only works for companies with public engineering presence, requires technical knowledge to interpret
9. Use Sales Intelligence Tools
The fastest way to get comprehensive technographic data at scale. These platforms aggregate technology usage data across millions of companies automatically.
Manual Steps
- Search for companies using a specific technology
- View a company's complete tech stack in one place
- Find customers of your competitors' products
- Set up alerts when companies adopt or drop technologies
Tools
How TheirStack works: TheirStack tracks over 40,000 technologies and identifies which companies use them. Want to find all companies using Salesforce in the healthcare industry? A single search returns a filtered list with company details and contact information.
Pros: Comprehensive coverage, continuously updated, saves hours of manual research, scales to thousands of companies
Cons: Requires a subscription, data accuracy varies by provider
Combining Methods for Best Results
No single method gives you the complete picture. Here's a practical workflow:
- Start with sales intelligence tools to get a baseline tech stack and identify target companies
- Check StackShare for self-reported stacks and additional context
- Look up subprocessor lists for B2B tools and infrastructure
- Validate with job postings for technologies that aren't externally visible
- Check DNS records to confirm infrastructure choices
- Inspect websites to confirm front-end technologies
This combination gives you both breadth (thousands of companies) and depth (validated, detailed information).
What to Do With This Information
Once you know a company's tech stack:
- For sales: Reference specific integrations in your outreach. "I noticed you're using HubSpot—our tool syncs directly with your existing workflow."
- For competitive analysis: Track how many companies switch from competitor A to competitor B over time.
- For product development: Identify which technologies your target customers use most, and prioritize those integrations.
- For ABM campaigns: Build audience segments based on technology usage, not just firmographics.
Getting Started
If you're doing this manually for a handful of companies, the free methods work fine. Job postings, DNS lookups, and subprocessor lists cost nothing but time.
For ongoing prospecting or research at scale, a tool like TheirStack pays for itself quickly. You can search by technology, industry, company size, and location—then export lists directly to your CRM.
The companies you're trying to reach are using specific tools right now. The question is whether you'll find them before your competitors do.