Amazon

SCOPE CAVEAT — the two surfaces you named most specifically are the two I could NOT verify. Everything in the table marked "verified" was read directly off a public first-party Amazon page; the four "unverified" rows are deliberately left as gaps. WHAT WOULD NOT FETCH: 1. sellercentral.amazon.com/help/hub/* — hard login wall. Every request 302s to na.account.amazon.com/ap/sso (Amazon OpenID sign-in). This is where the seller listing video / main-image video requirements and the A+ authoring guidelines actually live. I attempted a specific help-article ID and got the sign-in redirect; I have not cited that ID because I could not confirm it is the current video article, so the unverified rows cite the login-gated help hub root instead. 2. sell.amazon.com/tools/a-plus-content, /learn/a-plus-content, /tools/product-videos — all 404. These slugs do not exist. 3. advertising.amazon.com/en-us/resources/ad-policy/creative-acceptance — returned only Amazon branding and a tracking pixel, no readable policy body (likely JS-rendered). No video rules extracted. 4. brandservices.amazon.com/aplus — 301s to sell.amazon.com/brand-registry (marketing page, no specs). A+ CONTENT — THE USEFUL FINDING: the module-count limit is asymmetric and this is the rule that trips people up. Per Amazon's SP-API docs, "Content documents for selling partners can contain up to seven modules; content documents for vendors can contain up to five content modules." Same A+ system, different cap depending on whether you are a seller or a vendor. A+ AND VIDEO: Amazon's public A+ Content API module enumeration lists 15 standard module types and none of them is a video module. So standard A+ (the kind you build via API, and the kind most sellers have) has no video at all — video in A+ only exists in Premium A+, which is authored in the login-gated UI. If someone hands you "A+ video specs" from a blog, that is Premium A+ and I could not confirm any of its numbers first-party. URL / REDIRECT NOTE: developer-docs.amazon.com/... 301s to developer-docs.amazon/... (Amazon owns the .amazon TLD). I fetched the .amazon form; I cite the .amazon.com form because that is the documented, browser-resolvable address. Content is identical. LOCALE NOTE: advertising.amazon.com serves by geo. My first fetch of the Sponsored Brands Video spec page returned Spanish. I re-fetched the /en-us/ path and the numbers were identical across both locales — no discrepancy, but always use the /en-us/ path for verbatim English quoting. NO CONTRADICTIONS FOUND between the pages I did read, but note they are genuinely different surfaces and their numbers differ legitimately — do not merge them. Four different max durations coexist: Sponsored Brands Video 6-45s, DSP online video 6-120s, custom-media video up to 3 minutes (15s on Fire tablet), Stores background video 2-20s. Likewise file size is 500MB on three surfaces but the containers differ (SB Video accepts only .MP4/.MOV; DSP OLV accepts eight containers; Stores accepts MP4 only). ASPECT RATIOS: the ratiosAccepted list is a union across surfaces and is misleading if applied blindly. 16:9 is the ONLY ratio Sponsored Brands Video accepts. 9:16 is DSP-only and further restricted — "available on Twitch and Amazon Publisher Direct only." The 6:4-to-8:3 and 3:4-to-4:3 entries are Stores video tiles and are expressed by Amazon as ranges, not fixed ratios. CHANGE HISTORY: I could not establish what changed in the last 12 months. Amazon does not publish changelogs or "last updated" dates on these ad-spec pages, and my web-search budget for this session was exhausted before I could check archived versions, so I have no basis for a change claim. Treat all of the above as "current as of the fetch date," not as "unchanged since 2025." RECOMMENDED NEXT STEP for the gaps: the listing-video and Premium A+ numbers require an authenticated Seller Central session. Log in and pull them from Seller Central Help directly, or from the Upload Video tool's own on-page validation text, which states the live limits the uploader actually enforces.