Corridor Key vs Knockout API

Corridor Key is a free browser-based AI green-screen keyer that removes a video background and replaces it with a solid color, still image, or video. It accepts standard MP4 clips and returns re-encoded H.264 MP4 files. The service says its AI preserves details including flyaway hair, fur, glass, eyewear, and sheer fabric. Fast Mode processes an eight-second clip in seconds; Full Mode takes longer for sharper edge detail. No account or installation is required, and the free plan has no daily or monthly usage cap, although each clip can be up to eight seconds. It runs in desktop, tablet, and mobile browsers, with processing on its servers. Uploaded clips are sent to a Hugging Face Space running BiRefNet. Corridor Key says it does not store clips or outputs on its own servers; Hugging Face terms apply while files are there. HTTPS protects transmission. Availability can depend on Space downtime or GPU queues, and quality varies with edges, motion, lighting, and source quality.

Knockout API provides image and video processing through a browser app and API. Its image tools cover background removal and replacement, batch processing, masking, smart crop, stickers, outlines, shadows, and inpainting; the API also handles upscaling, portrait restoration, colorization, and object removal. Video background removal runs asynchronously, with job polling for progress. The browser Canvas supports layered designs with text and effects, and users can save canvases and cutouts to a free account. Developers can connect through REST, any HTTP client, or official Node, React, Python, and CLI options. The service says it manages GPU processing, endpoint updates, usage records, credentials, teams, and billing. Its privacy policy says uploaded images are processed in GPU worker memory, not retained after the response, and not used to train models. The Free plan is free, with 30 images per month and 60 requests per minute. Pay-as-you-go is $0.02 a month, with metered usage billed monthly; Plus is $10 a month. Paid tiers have no monthly cap and a 600-request-per-minute limit.