AI Software Engineer (LLM Systems)

About Cosign.ai Labs, Inc. Cosign.ai Labs is building the control layer for AI-powered decision making. Most AI products today generate answers. That’s not the hard part anymore. The hard part is deciding what should be done, what risks are acceptable, and when humans should step in. That’s where Cosign comes in. We build systems that sit on top of large language models and turn them into structured, governed workflows. Instead of asking AI for opinions, our platform encodes rules, judgment frameworks, and escalation paths so users can actually act on AI outputs with confidence. Our first product focuses on contracts. Cosign helps individuals and companies analyze, draft, and negotiate agreements using AI—without needing to be legal experts. Under the hood, we combine LLM reasoning with deterministic logic to produce structured outputs that are consistent, auditable, and aligned with user-defined risk tolerance. We’re not trying to replace professionals. We’re building tools that let people operate at a much higher level, with AI handling the heavy lifting and Cosign ensuring it stays within guardrails. Role Summary Design and build the core AI systems powering Cosign.ai. This includes LLM integrations, agent workflows, and scalable backend systems. What You’ll Do Build and optimize LLM-powered features (analysis, drafting, automation)Design agentic workflows combining reasoning + deterministic systemsIntegrate APIs, embeddings, vector databases, and retrieval systemsImprove latency, cost efficiency, and reliability of AI systemsWork closely with product to ship fast and iterate based on usageStay on top of new models, tools, and capabilities (and actually use them) Requirements Strong experience in backend engineering (Python, Node, etc.)Deep familiarity with LLMs, prompt design, RAG systems, and agent frameworksExperience with real-world AI product deployment (not just demos)Ability to balance speed vs. quality in a startup environmentMild obsession with making things work better, faster, cheaper Base Salary $140K – $200K Equity 1.0% – 3.0%