Founding Engineer (AI + Backend)

About OpenFunnel

OpenFunnel helps connect great B2B SaaS products to companies who need them.

For all of outbound history, GTM teams have relied on blind outbound automation. With AI in the picture, it has gotten worse - it's turned automation into a slop cannon, destroying helpful and relevant outreach in favor of volume spam.

We believe the exact opposite. AI should narrow the search and sharpen the timing, not flood inboxes.

At OpenFunnel, we are building a Real-time Data Engine for GTM Teams and Agents.

Our goal is to achieve near 100% outbound conversion rate, while the state of the art sits at 4%.

We work with the fastest-growing B2B companies, are backed by top investors.

About The Role

We're looking for a Founding Engineer to own and build core backend, search and AI infrastructure at OpenFunnel. You'll work across the full depth of our stack - from queries over hundreds of millions of records, and LLM-powered inference pipelines, to the agentic systems that tie it all together. You'll design and ship systems that process data at scale, extract intelligence from unstructured sources, and power real-time alerting for our customers' sales teams. You'll work directly with the founders and have outsized impact on the product and architecture.

What You'll Work On

• Large-Scale Data Infrastructure

You'll build pipelines that process and enrich data across 45M+ companies and 1B+ people profiles - making messy, unstructured B2B data inference-ready, queryable, accurate, and fast. Think: real-time change detection across 1B scale data sources, and pre-computed aggregate insights that power instant answers.

• LLM Systems

You'll design AI systems that go well beyond simple prompting - compound agents that combine web search, structured data, and multi-step reasoning to qualify events, score them, and surface action steps.

• Integrations & Operationalization

You'll build the connective tissue between OpenFunnel and our customers' GTM stacks - bidirectional CRM sync with Salesforce and HubSpot, batch replication pipelines, and signal tagging systems that make our data actionable inside the tools sales teams already use.

What We're Looking For

• Strong systems builder. You've designed and shipped backend systems that handle real scale - batch processing, concurrent pipelines, large datasets.
• AI/LLM fluency. You've built with LLMs beyond demo apps - structured outputs, prompt engineering for classification at scale, agentic tool-use patterns. You understand the tradeoffs between models, cost, latency, and accuracy.
• Data infrastructure instincts. Comfortable with analytical databases (ClickHouse, BigQuery), PostgreSQL, search engines (OpenSearch/ElasticSearch), and building pipelines.
• Speed and precision. You ship fast without shipping broken. You care about data correctness - wrong dates, duplicate records, and silent failures bother you.
• Ownership mentality. You don't wait for specs. You see a messy problem, decompose it, build the first version, and iterate. You treat the system as yours.

Nice to Have

• Ex-founder or early-stage startup experience - you know what building from zero feels like.
• Familiarity with search infrastructure, NLP, or information extraction.
• Experience with B2B sales/marketing data, CRM systems, or GTM tooling.

Why Join OpenFunnel?

• Founding-level impact. You'll shape the architecture, the product, and the company. This is employee-level equity with real upside.
• Hard, interesting problems. Extracting intelligence from messy, large-scale B2B data.
• Small team, fast loops. No layers, no process theater. You ship code and it's in production the same day.
• Work with real customers. Your systems power pipeline for some of the most innovative GTM teams in the market.
• Competitive salary and meaningful equity.