Using video/GIF testimonials in cold outreach almost always hurts deliverability.
What works best is to not send the video at all in the first email — instead:
Winning approach:
- 1.
- 2.
Social proof in one sentence (“helped X, Y, Z get 3–5x conversion improvements”)
- 3.
- 4.
Link to testimonial only in follow-up after they reply or engage
If you really want it in the first email, use a text-only link disguised as a case study, not as a “video link.”
Never embed, never attach, never use GIF previews.