CheckSafe.Zone
for marketers
CheckSafe.Zone
for marketers
Built by a digital marketer who got tired of avoidable mistakes
CheckSafe.Zone was built out of daily frustration. Working in digital marketing and ad operations, I kept seeing the same problems over and over: videos going live on TikTok with text buried under the like button, HTML5 banners getting rejected by CM360 for missing clickTags or exceeding the 150 KB limit, clients approving creative that looked clean on their desktop but was unusable in-feed.
Every fix meant opening a new browser tab, searching for yet another resource, and hoping the numbers you found were actually current. Platform UIs change. Safe zone guides go stale. There was no single tool that let you drop in a file and immediately see where the danger zones were — without uploading anything to a server or requiring a login.
So I built one. Then I built a second one for banners.
The Safe Zone Checker overlays platform-specific danger zones directly onto your video or image. It covers TikTok (Feed and Ads), Instagram Reels (Feed and Ads), Instagram Stories, YouTube Shorts, Snapchat, and TV Broadcast — with exact pixel measurements derived from testing against live platform UIs at 1080×1920. It handles both organic and paid placements, because the safe zones are different and conflating them is a common mistake.
The HTML5 Banner Validator runs pre-trafficking QC checks that ad ops teams would otherwise do manually: clickTag presence, file size against the 150 KB IAB/CM360/DV360 limit, IAB format identification, GIF loop count, and backup image detection. It previews HTML5 and GIF animations inside a sandboxed iframe so you can actually see what the ad server will receive.
Neither tool ever transmits your files to a server. Everything runs in the browser using native APIs: the HTML5 Canvas API for the overlay, the File API and JSZip for banner parsing, and the native <video> element for video playback. This matters for agencies handling pre-launch or NDA-protected creative — there is no risk of a file appearing in server logs or a third-party cache.
Once the page loads, both tools work fully offline.
Content creators checking their videos before publishing. Motion designers verifying text placement. Social media managers who want to know whether a repurposed asset will work on Reels before it goes live. Media buyers running pre-launch QC on HTML5 creatives. Ad ops teams that need a fast sanity check before trafficking. Anyone who has ever had a campaign rejected or a video go live with UI elements covering the key message.
Questions, bug reports, or platform spec corrections: filip.djordjevic447@gmail.com
If the tool saves you time, a coffee is always appreciated.