Graded B+ on resilience. In Vannus's assessment it builds its own AI model — resilient — owns model IP or routes across providers.
HeyGen has three avatar rendering engines, all available on the v3 API
Vannus grades HeyGen against nine dimensions of trust — data sovereignty, training privacy, compliance posture, operational resilience, exit portability, and more. The heaviest criterion asks whether the tool builds its own AI or resells someone else's model; where the vendor discloses it, the grade cites the vendor's own documentation. No paid placements — scoring is walled off from affiliate revenue. See the methodology →