Sandie shows up at rank #3328 with all 25 recorded uses going to female pets — a warm, cheerful diminutive that sits in a distinctly different register from its more formal root Sandra. Where Sandra carries mid-century office authority, Sandie is the dog who has already made friends with everyone in the waiting room before you've finished the intake form.
The diminutive logic
Sandie is a softened form of Sandra, which itself derives from Alexandra — the feminine of Alexander, meaning "defender of men" in Greek. By the time you've traveled from Alexander through Sandra to Sandie, most of the martial gravity has evaporated, leaving something bright and approachable. The "-ie" ending does a lot of work in pet naming: it signals affection, diminution, and a certain casual warmth. Sandie belongs in the same phonetic family as Maggie, Rosie, and Cassie — all enormously popular pet name patterns.
Sandy vs. Sandie — the spelling distinction
The "ie" spelling rather than "y" is a small but deliberate choice. Sandy-with-a-y is more common in both human and pet use; Sandie-with-ie is the specifically British variant, and it carries a slight vintage quality that some owners find appealing. It shows up with some frequency on Golden Retrievers — the coat color connection to the word "sandy" is almost certainly part of it — and on friendly, high-energy Labrador Retriever females.
The owner who chooses Sandie
This is a name for someone who wants warmth and approachability without any ironic distance. Sandie owners are probably not trying to make a statement — they found a name that felt like the dog. It pairs well with a longer, more formal surname if you ever need to use the full name at the vet. If you're considering this register, Margie, Maggy, and Tinka are close neighbors in both sound and feel.