Your CRM can tell you who the CFO at your top account is. It can't tell you that your head of product worked beside her for four years at her last company.

That second fact is the one that gets you the meeting. It's also the one most sales stacks never capture, because nobody logs a relationship that started before they joined.

Warm introduction software finds connections like that across your whole company, board and investor base, then helps you ask for the intro.

What is warm introduction software?

Warm introduction software finds the people in your network who already know someone you want to meet, scores how strong each relationship is, and helps you ask for the introduction. It maps who knows whom, so you can reach a buyer, investor or candidate through someone they trust.

A contact database lists people and how to reach them. Warm intro software adds who can vouch for you: which colleague or investor knows that person, and how well. If you're new to the idea, start with what a warm intro is.

Why teams use warm introduction software

Warm intros have always worked. Finding them is the hard part. In Norwest Venture Partners' 2025 survey of 177 B2B sales and marketing leaders, 65% picked warm referrals from customers or their network as one of their most effective outreach tactics. The next tactic on the list, inbound lead follow-up, came in at 44% (Norwest).

AI has also made reach cheap. About three in four sales teams in the same survey use AI on at least some of their outbound email, so buyers' inboxes are filling with well-written messages from strangers. The scarce part now is trust: a person the buyer already knows who's willing to make the introduction.

Warm introduction software turns that from a lucky Slack reply into something a team can run every week.

Where does the relationship graph come from?

Every warm intro tool is limited by its relationship data. A tool can only find paths that exist in the data it reads, so the source decides which introductions you'll ever see. There are four common models.

None of these models is wrong. Your own activity data is accurate about relationships your team uses today. A pre-built graph can find paths nobody on your team has written down. Many teams want both, which is why some tools, Vieu included, combine a pre-built graph with data you choose to connect.

What to look for in a warm introduction platform

Graph source and coverage

Ask where the relationships come from and how many people and companies are covered. If the tool only reads your inboxes, it will miss your board's and investors' networks unless they connect theirs too.

Relationship strength and recency

A board seat shared in 2019 and last year's manager are different paths. Good tools score each relationship and show the evidence, such as years overlapped at an employer, so you can judge whether the introducer will actually vouch for you.

Whose network counts

The best introducer is often outside the sales team: an executive, a board member, an investor, an advisor, a customer or a partner. Check which of these the tool includes, and whether each one has to sign up before their relationships appear.

How the ask works

Finding the path is half the work. Look for a forwardable email the introducer can send as-is, plus double opt-in and tracking so the target agrees first and nothing stalls in someone's inbox.

Where it lives

If reps have to open another tab, they won't use it. Check whether the tool works inside your CRM, email or Slack, and whether shortlisted intros sync back to the CRM.

Agent access

More account research now happens inside AI assistants. Check whether an assistant such as Claude or Gemini can query the tool directly through an MCP server, or whether a person has to click through a UI.

Privacy and consent

Ask whose inbox is being read, who approved it, and what happens to that data. Tools built on email and calendar sync need each connector to opt in. Tools built on public records should say exactly which sources they use.

Warm intro tools compared: Vieu, Affinity, Sales Navigator TeamLink and Crossbeam

Each of these is built for a different purpose, so compare them on graph source first.

1. Vieu

Vieu's graph exists before you connect anything. It covers 4 billion people and companies and 14 billion relationships, built from shared work history, board affiliations, co-authored research and joint ventures. It's a business graph built from inferred and verified relationships, drawn from records rather than connections people chose to add. So a path can show up even when nobody on your team has ever emailed the person.

Take a common case. Your CEO's former colleague is now a senior leader at your top target account. They never connected on LinkedIn and haven't emailed in years, but they spent five years on the same team. Vieu finds that path, scores its strength, and names your CEO as the introducer.

Teams can also connect work email, calendar and CRM to add their own signals, though it's optional. When you're ready to ask, Vieu drafts the note to the introducer and a forwardable message for the target, sends the request in Slack, and syncs shortlisted intros to your CRM. Nobody is contacted until the introducer agrees.

If an AI agent is doing the research, a Vieu graph query returns in about 287 milliseconds. Vieu puts an LLM searching the open web for the same answer at around 40 seconds . You can also query it from Claude or Gemini through Vieu's MCP server.

Vieu covers six use cases, from sales to fundraising, explained below.

2. Affinity

Affinity is a CRM built for private capital: private equity, venture capital, private credit and family offices. Its relationship intelligence syncs firmwide email and calendar activity, enriches profiles from 40+ sources, and scores connection strength to show who at the firm has the warmest path to a founder or LP. It also has an MCP server for Claude, ChatGPT, Copilot and Gemini.

It's strong for deal flow and LP relationships, and Affinity describes itself as purpose-built for private capital rather than general B2B selling.

3. Sales Navigator (TeamLink)

TeamLink shows which of your colleagues are connected to a prospect on LinkedIn. It's included on Sales Navigator Advanced and Advanced Plus, and TeamLink Extend lets colleagues without a seat opt in to share their connections.

It runs on your team's own LinkedIn network, so it sees the ties people chose to add. Different purpose, different graph: useful for LinkedIn-first prospecting, limited to accepted connections. For a fuller comparison, see our guide to LinkedIn Sales Navigator alternatives.

4. Crossbeam

Crossbeam compares your CRM account list with your partners' lists to show overlap: shared customers, prospects and open opportunities. That's useful for co-selling. It works at the company level, so it tells you which partner knows an account rather than which person knows your buyer.

Many teams run Vieu alongside one of these rather than instead of it: Affinity as a fund's deal CRM, Sales Navigator for LinkedIn research, Crossbeam for partner programs.

Who uses warm introduction software

Sales gets most of the attention, but the same graph works anywhere a trusted intro gets further than a cold message.

Sales

AEs and founders find executive paths into strategic accounts, so the first meeting happens with the economic buyer. It also helps multithread a deal once you're in.

Marketing

Marketers use relationship data for event and ABM targeting: inviting executives the company can actually reach, and personalising campaigns around shared connections.

Partnerships and BD

BD teams map relationships between companies to find who can open a partnership conversation at the right level.

HR and talent

Recruiters use warm intro paths for senior hires, including back-channel checks with people who worked beside the candidate.

Customer success

CS teams use it for executive engagement before renewal, finding an exec-level path when the day-to-day champion has left or the renewal needs a sponsor.

Fundraising

Founders look for warm investor introductions through existing investors, advisors and portfolio founders. The graph shows which of those people already know the partner you want to pitch.

Once the software finds the path, you still have to ask

The software gets you to the right person. How you ask decides whether the introduction happens.

If you're working out how to get a warm intro, three habits matter most: send a short forwardable email the introducer can pass on without rewriting, use double opt-in so the target agrees first, and make it easy for the introducer to say no. For the full playbook, see how to ask for the intro.

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FAQ

What's the difference between a warm and a cold introduction?

A warm introduction comes from someone the recipient already knows and trusts, who vouches for you before you make contact. A cold introduction, usually a cold email or call, reaches someone with no shared connection. Warm intros tend to get replies because the introducer's trust comes with them.

Is warm introduction software the same as relationship intelligence software?

They overlap. Relationship intelligence software scores who knows whom and how well, often inside a CRM. Warm introduction software uses that kind of data to find the best path to a specific person, then adds the ask: drafting, sending and tracking the intro. Some tools, Vieu included, do both.

Can I use Sales Navigator for warm intros?

Yes, with limits. TeamLink on Advanced and Advanced Plus shows which colleagues are 1st-degree LinkedIn connections of a prospect, and TeamLink Extend adds opt-in colleagues without a seat. It only sees LinkedIn connections, so paths through former colleagues, board seats or investors who never connected won't appear.

Does warm intro software need access to my email?

It depends on the graph model. CRM-style tools such as Affinity build their graph from email and calendar sync, so each connector has to opt in. Vieu starts from public records such as work history and board seats, and connecting email, calendar or CRM is optional.

Can AI agents use warm introduction software?

Some can, and warm intro AI is increasingly where account research happens. Vieu, Affinity and Crossbeam all offer MCP connections, so an assistant such as Claude or Gemini can query relationship data directly. Vieu's graph answers a path query in about 287 milliseconds, fast enough to sit inside an agent's research step.

How many warm intro paths do teams usually find?

It depends on the size of your company's network and how many accounts are on your target list. The quickest way to find out is to run your own list through a tool and count how many accounts have at least one high-strength path. That's what the free intros offer below is for. For accounts without one, warm referrals from customers can fill some of the gap.

Bring a list of accounts you care about and see which ones you already have a way into.

Get your first 25 intros free →

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