FDE vs Solutions Engineer, Sales & Applied AI Engineer

Every adjacent role can be placed on two axes: where it sits in the customer lifecycle, and how much production code it writes. The FDE is the role that sits post-sale, in production, and codes most of the week while owning the outcome. Hold that fixed and the rest fall into place.

Solutions engineers and architects live mostly in the late pre-sale and early post-sale window. Their mandate is to map product capabilities to a customer's requirements and design the solution — demos, proofs-of-concept, advisory. They code, but mainly for PoCs, and they're rewarded for design and advice rather than operational ownership. The FDE builds what doesn't exist yet and keeps it running; the SE sells and designs the vision of what could exist.

A sales engineer is pre-sale and sales-first: provide the technical validation that closes the deal, then move to the next opportunity. Coding is light. The FDE picks up after the deal and is measured on whether the thing actually works in production months later.

These are largely the same role under different titles. "Forward Deployed Engineer" (Palantir, OpenAI) tends to emphasize integration and deployment depth; "Applied AI Engineer" (Anthropic and many AI startups) tends to emphasize AI quality and evaluation rigor. Both embed with customers and ship production AI. If you're choosing between postings, read the responsibilities, not the title.

A customer success / customer engineer works post-go-live to protect and expand the account — onboarding, troubleshooting, ongoing support. The framing that sticks: FDEs accelerate getting to production; CS engineers protect and expand once you're there.

A professional-services consultant installs and configures software and makes one-off recommendations, often independent of product engineering. The FDE works with a customer long-term and routes insights back into the product, so a field solution can become a feature the whole user base benefits from — the opposite of a one-off customization.