GTM Data Engineer: Waterfall Enrichment & List Building for M&A - Technical Expert Needed

GTM Data Engineer — Clay Waterfall Enrichment & List Building for M&A (Fractional, 12 hrs/wk) About us we are a venture capital fund-backed, M&A advisory firm in London. We sell essential-service businesses in niches like fire safety, building services, facilities management, and healthcare. We run a modern outbound stack and need one technical operator to own our data and enrichment engine. This is a systems role, not an admin role. If you think in pipelines, dedup logic, and match rates, read on. If you think in "I'll research your leads manually," this is not for you. What you will do Aggregate leads from all our sources (events, referrals, SEO, direct research) into one clean, deduplicated pipeline Build two list types: buyer/acquirer universes (PE funds, search funds, roll-ups, strategics, family offices) and seller/target universes (qualified companies that fit acquisition criteria) Find a minimum of two decision-maker contacts per company. If the first enrichment pass does not return two, you go and find them. Build and maintain Clay waterfalls: chain multiple providers in priority order, clean before enriching, protect credits Use AI agents, MCPs, APIs, scrapers and prompting to surface non-obvious signals: founder or director age, succession risk, company performance, location fit Write natural, native-English personalisation lines that read as human-written to US and UK business owners, many running 50-70 year old family firms Own email deliverability: SPF, DKIM, DMARC, domain warmup, inbox-placement monitoring across Google and Microsoft Manage WhatsApp Business API outbound: quality rating, tier progression, opt-in discipline, number and portfolio health Deliverables Lemlist-ready CSVs in a fixed ~30-column schema we provide, camelCase, zero data loss, verified before delivery Weekly enrichment output tied to live campaigns Continuous email and WhatsApp sending-health monitoring with proactive flags before anything breaks A short methodology note per list: sources used, waterfall order, exclusions Skills required (non-negotiable) Prior list-building and enrichment work for an M&A advisory firm, brokerage, PE fund, or search fund. Not adjacent work. This exact work. Portfolio or references required. Expert-level Clay, including waterfall enrichment, filtering, dedup, and computed columns Expert-level Lemlist or a direct equivalent Fluent with MCPs, APIs, AI agent prompting, and stitching multiple tools into one reliable workflow Email deliverability expertise current as of 2026 (Google and Microsoft enforcement, SPF 10-lookup limit, warmup, bounce and complaint thresholds) Native or childhood-fluent English, demonstrated in writing Strong plus WhatsApp Business API experience, or clear evidence you learn technical systems fast Python or SQL Companies House (UK) or US registry and licence-board sourcing Access and support provided Claude account and credits, Lemlist, Clay, WhatsApp Business API, relevant MCPs and API keys. If you need a specific enrichment tool, more credits, or access to anything to do the job well, you tell me and I provide it. I remove blockers fast. In return I expect you to raise them fast. How I work, and what I expect from you Communicate in a structured way. Before a task: tell me what you are going to do and the process. During: flag progress. After: tell me what you did and what the output is. Surface bottlenecks the moment they appear. If you are blocked on credits, a tool, access, or a decision, tell me immediately with the specific thing you need. Do not wait. Do not sit on it. Do not quietly deliver less. Be direct. No wishy-washing, no vague hedging, no "it depends" without a recommendation. If you disagree with an approach, say so and say why. Have a backbone. Take instructions, execute accurately, and push back when you have a real reason. I want a reliable operator with a spine, not a yes-machine and not someone who goes silent when stuck. Precision matters more than speed. Deduplication, two contacts per company, verified data. Attention to detail is the job.