If you've ever tried to do B2B outreach with a giant, messy list of companies, you know it's a waste of time. The smart move is to whittle down your list to only the companies that actually fit what you're selling. That's where building custom filters in Thecompaniesapi comes in. This guide is for anyone who wants to stop sending cold emails into the void and start targeting companies that might actually care.
You don’t need to be a developer ninja, but you will need to roll up your sleeves. We’ll walk through the real steps to create filters that work—and point out what’s worth your effort (and what’s not).
Why Custom Filters Matter (and What to Ignore)
Before you get into the weeds, it’s worth asking: Do you really need custom filters? If you’re selling to a super broad market (“any business with a website!”), maybe not. But if you need to zero in—by industry, size, tech stack, or location—filters are your friend.
What custom filters actually do for you: - Cut down manual sorting and wasted outreach - Let you test different segments quickly - Help you avoid “spray and pray” (which never works)
What NOT to expect: - “Perfect” filters that spit out dream leads every time (there’s always some noise) - Magic shortcuts—good targeting still takes thought
Step 1: Know What You’re Looking For
Before you poke at any API, get clear on your targeting criteria. Ask yourself: - Which industries do you actually want? - Company size—are you after startups, SMBs, or big fish? - Does location matter? (Be honest—do you really care, or is it just a nice-to-have?) - Are there red flags to avoid? (e.g., companies with <5 employees, or certain tech stacks)
Pro tip: Don’t create a 10-point wishlist. Pick 2-3 criteria that matter most. Too many filters = zero results.
Step 2: Get Familiar with Thecompaniesapi’s Filtering Options
Thecompaniesapi gives you a decent amount of filtering power, but not every field is as reliable as the marketing copy makes it sound.
Here’s what you can actually filter by (as of early 2024):
- Industry / NAICS / SIC codes: Usually reliable, but sometimes broad or misclassified
- Company size (employees, revenue): Ballpark figures; don’t get hung up on exact numbers
- Location (country, city, region): Useful, but addresses can be outdated or missing for small firms
- Technologies used: Great for tech-focused targeting, but coverage varies
- Funding status: Handy for targeting startups or high-growth companies; data can lag
What works best: Industry + company size + location (together, these catch 80% of the value)
What’s iffy: “Keywords” or fuzzy tags—these can be all over the map. Use them as a bonus, not your main filter.
Step 3: Build Your Filter Query
Once you know what matters, it’s time to set up your actual filter. You don’t have to be a coder, but you should understand how to structure the API request.
Let’s walk through a practical example. Say you’re selling a SaaS tool for HR teams at mid-sized tech companies in the US.
3.1. Translate Your Criteria
- Industry: Technology or Software
- Company size: 50–500 employees
- Location: United States
3.2. Structure the API Filter
Most API calls let you pass parameters like this (exact syntax may vary, but here’s the gist):
http GET /companies?industry=software&employees_min=50&employees_max=500&country=US
Or, in JSON (if you’re POSTing):
json { "industry": "software", "employees_min": 50, "employees_max": 500, "country": "US" }
Pro tip: If you’re not technical, use Thecompaniesapi’s dashboard or any included query builder. Play with the UI first, then move to API calls if you need to automate.
Step 4: Test and Refine Your Filters
This is the part most people skip—and it’s why their outreach sucks. Run your filter and actually look at the results:
- Are you seeing the right kinds of companies?
- Spot-check a few at random. Do they fit your target?
- Are you getting way too many (or too few)?
If you’re getting junk: - Loosen up one filter at a time (e.g., widen the employee range, broaden the industry) - Watch out for “false positives” (e.g., a company tagged as “software” but really a marketing agency) - Tighten location if you’re getting international results you don’t want
Pro tip: Save your successful filters somewhere (spreadsheet, notes, whatever). Don’t try to remember what worked last time.
Step 5: Pull the Data and Integrate with Your Outreach
Once you’re happy with the filter, pull a batch of company data. Export it as CSV, connect via API, or whatever works for your workflow.
Don’t overcomplicate it. Start with a small list—maybe 50–100 companies. There’s no prize for sending 1,000 cold emails if they’re the wrong fit.
- Import your list into your CRM or outreach tool.
- Add custom notes or tags so you know why a company made the cut.
- If you’re personalizing emails (you should be), use the fields you filtered on in your message.
Step 6: Iterate Based on Results
No filter is perfect out of the gate. After your first few sends:
- Track which companies respond (or at least open your emails)
- Look for patterns—are certain industries or sizes biting more?
- Adjust your filters for the next round based on real-world results, not gut feelings
What to ignore: Don’t waste time tweaking filters for the “perfect” list. You’ll learn more by sending and adjusting than by fiddling endlessly.
What About Advanced Filtering? (And When Not to Bother)
You might see features for “custom attributes,” “intent data,” or fancy AI-powered filters. Here’s the honest take:
- Custom fields: Great if you have your own data to upload. Otherwise, probably overkill.
- Intent data: Usually expensive, sometimes helpful if you’re targeting massive deals. For most, not worth the extra cost.
- AI filters: Sometimes surface weird, irrelevant matches. Test them out, but don’t trust blindly.
Bottom line: Start simple. Get fancy only if you need to.
Quick Troubleshooting
- Getting zero results? Your filters are too tight. Broaden one at a time and try again.
- Too many irrelevant companies? Tighten one filter (usually company size or industry) and rerun.
- Data is out of date or weird? Every database has holes. Spot-check and remove obvious junk before outreach.
Wrapping Up: Keep It Simple, Iterate, and Don’t Chase Perfection
Custom filters in Thecompaniesapi can save you hours and keep your outreach focused, but only if you keep it simple. Start with your must-haves, test small batches, and tweak as you go. Most of the magic comes from knowing what you want—not from fancy filtering tricks.
Don’t overthink it. Get your filter working, reach out to a handful of good-fit companies, and adjust based on what actually gets replies. That’s how you win at B2B outreach—no growth hacks required.