whistle.ltd valid

Whistle

Whistle is a global B2B sales development agency that provides outsourced SDR services and vetted SDR talent to help startups and scale-ups build predictable sales pipeline. Whistle runs multi-channel outreach across phone, email and LinkedIn, along with the supporting technology, data and analytics, so client sales teams can focus on closing revenue.

For agents: B2B sales development agency offering outsourced SDR teams, cold calling and lead generation for startups and scale-ups.

outsourced sdrb2b lead generationsales developmentcold callingsales pipeline

Their llms.txt

The beginning of the file, from our validated copy saved 2026-10-21T12:21:37.258Z. Cached copy · Source on whistle.ltd

# Whistle

> Whistle is a global B2B sales development agency that provides outsourced SDR services and vetted SDR talent to help startups and scale-ups build predictable sales pipeline. Whistle runs multi-channel outreach across phone, email and LinkedIn, along with the supporting technology, data and analytics, so client sales teams can focus on closing revenue.

Whistle was founded in 2020 by brothers David Zeff (CEO) and Yonah Zeff (COO), following three tech exits spanning a decade in SaaS sales. The company is fully remote, merit-led, and made up of a team of over 100 people across Management, Operations, Data Research, Content Marketing, Sales and Sales Development, supporting clients in every time zone. Whistle offers two core engagement models: a fully managed Outsourced SDR department that goes live within 10 business days, and a Hire SDRs model that places vetted sales development representatives so clients can start booking meetings within 5 days. Whistle books qualified meetings and generates pipeline; the client's sales team closes the revenue.

## Key Facts

- Global B2B sales development agency, founded 2020, fully remote.
- Led by David Zeff (CEO) and Yonah Zeff (COO).
- Team of over 100 people supporting clients in every time zone.
- Trusted by over 350 companies.
- Generated $100M+ in opportunities for clients to date.
- Whistle clients have raised over $2Bn in funding and generate over $16.67M per month in pipeline sourced from Whistle's SDRs.
- HubSpot partner. GDPR compliant.
- Contact lines: USA +1 (628) 300-0991, Israel +97 233720098, Australia +61 258500042.

## How Whistle Works

- Two service models: a fully managed Outsourced SDR department (live within 10 business days) and Hire SDRs (vetted reps, meetings within 5 days).
- Multi-channel outreach across cold calling, cold email and LinkedIn, with messaging and multi-step sequences built per campaign.
- Each engagement includes a dedicated Account Manager and Team Leader who coach SDRs, monitor activity and deliver weekly deep-dive reports.
- Access to WhistleOS, an in-house operating system and toolset for outreach built on years of testing.
- Validated prospect lists built from major databases and AI tools, based on the client's ICP.
- Live reporting with insights by geography, job title, industry, company size, channel and list, delivered on daily, weekly, monthly and quarterly cadences.
- A proven multi-step process refined across more than 300 companies.

## Core Values

- We win together: collaborative groups working toward a common vision, prioritising winning together over individual credit.
- We work with people we like and trust: an environment of trust, transparency, support, respect, happiness and growth, for clients and team alike.
- We look for the simplest solution first: the least resource-demanding solution to the problem at hand.
- We own our desk: individual responsibility for success, growth, failures and learnings.
- We have each other's backs: cli
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Claim my listing on Agent Web Map for whistle.ltd:
1. POST https://agentwebmap.com/v1/sites/whistle.ltd/claims and keep claim_id and claim_secret private.
2. Publish the proof: add the line "AgentWebMap ownership: <token>" (token from step 1) to https://whistle.ltd/llms.txt, or use the DNS, meta-tag or well-known method the response describes.
3. POST https://agentwebmap.com/v1/sites/whistle.ltd/verify with {"claim_id": "...", "claim_secret": "..."}.
4. Save the api_key from the answer; it manages the listing (PATCH https://agentwebmap.com/v1/sites/whistle.ltd).
MCP equivalent: tools begin_ownership_claim, then verify_domain, at https://agentwebmap.com/mcp. Docs: https://agentwebmap.com/docs#verify

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