Sency Alternatives, Routed by Why You Are Leaving

Disclosure: this site is funded by KinesteX, which sells a motion-tracking SDK that competes with Sency. KinesteX appears below in the groups where it genuinely fits, after the third-party options and labelled as ours. Every fact about every vendor comes from its own repositories, package registries or published pages as fetched on October 17, 2026; anything we could not verify is marked.

What you would be replacing#

Sency's SDK README describes "AI motion analysis technology that understands and enhances human movement through just a smartphone camera—no extra hardware needed". In practice that is two products sharing one engine:

• The Custom Kit (SMKit), which Sency's version table calls a "Native no-UI SDK". Its iOS demo states the division of labour plainly: you own the camera preview, session lifecycle, exercise UI, skeleton rendering and result presentation.
• The Branded Kit (SMKitUI), where "the entire user interface and experience are ready to use" as a white label.

Both kits cover iOS, Android, React Native and Flutter; Sency's own platform table marks JavaScript and Unity as not available. The README leads with initial movement and fitness assessments, monthly progress evaluations and personalized workout plans, and the iOS demo documents body calibration, adaptive range of motion and a session lifecycle. Sency also documents an MCP server for AI coding tools that need its SDK documentation, and its FAQ says data is "analyzed directly on the user's device, never sent to the cloud". Pricing is per monthly active user, counted once a month: its packages page lists a free Starter plan for up to 100 and a Growth plan from $499 a month for up to 3,800, while its main pricing page describes the first 100 as a paid tier after a free trial. Sency pricing sets out both.

Why teams look elsewhere#

These are the reasons the sources support:

• No web target. The platform table marks JavaScript "NA". A product with a browser or PWA surface needs something else for it.
• Models arrive from Sency's server. The iOS SMKit README says version 2.3.6 "downloads models and required SDK assets from the server" and "does not include bundled fallback models", so the first configuration needs a connection; a valid cache can be used offline later. The Android demo README says the same of SMKit Android 1.9.6. If a cold first launch must work offline, or you must pin model files in your own app, that is a structural mismatch.
• Commercial terms are a separate agreement. The LICENSE file in Sency's repositories is its Terms of Use, last updated in September 2022, and it says any commercial or production use is governed by a separate paid service agreement. It is not an open-source licence.
• A big first paid step, and two pages that disagree. Above the free Starter plan, Sency's packages page lists Growth from $499 a month, and its main pricing page describes the first 100 users as a paid tier instead. Sign-up runs through a contact form that leads to a call. Teams that want a cheaper first paid plan or one unambiguous price list look elsewhere.
• Platform floors. The Custom Kit's iOS demo pins iOS 16.0, and SMKitUI states iOS 15 or later. Teams still supporting older devices should check this first.

The alternatives, by reason for leaving#

You need a web or PWA surface#

• MediaPipe Pose Landmarker has a web Tasks API that runs in the browser, under Apache-2.0, with no key. You build the exercise logic. See MediaPipe Pose Landmarker models.
• MoveNet runs through TensorFlow.js; its SinglePose models are Apache-2.0. See MoveNet models.
• KinesteX, which funds this site, has HTML and JavaScript and PWA integrations that load its hosted experience in an iframe, alongside iOS, Android, React Native and Flutter SDKs that wrap the same experience in a WebView. See KinesteX vs Sency, written to the same disclosure standard as this page.

You want a cheaper first paid plan#

QuickPose publishes plans from $25 a month for up to 100 monthly active devices to $1,000 a month for up to 100,000, every SDK feature on every plan, with a free tier for 10 devices and a free SDK key. Units differ, devices against users, so model your own numbers. It is a MediaPipe-based toolkit of counters, range-of-motion measurement and overlays rather than an assessment and workout product, so compare scope as well as price: QuickPose vs Sency and QuickPose pricing.

Models must ship inside your app and work offline from the first launch#

• MediaPipe Pose Landmarker loads a .task file you can bundle and pin, which Google's own Android sample does with a versioned download URL.
• Apple Vision body pose runs from the operating system on iOS 14 and later (3D from iOS 17), with no model file at all. See Apple Vision body pose.
• ML Kit Pose Detection runs on Android and iOS under Google's terms; its Android guide says the API "uses a bundled library that increases your app size". Google labels it beta and says it detects one person. See ML Kit pose detection.
• QuickPose bundles MediaPipe libraries in its SDK modules and describes on-device inference.

Your product is clinical or regulated rehab#

Kemtai positions itself for that work: embeddable exercise and patient-management components, data APIs that pull exercise scores and range-of-motion results back into your system, a library of more than 2,000 exercises, processing on the device with no video recorded, and an FDA listing and CE marking as a medical device. Its API documentation is behind an email request and it publishes no prices, so expect a sales process.

You want an open-source licence end to end#

MediaPipe's framework and Pose Landmarker models are Apache-2.0, and MoveNet's SinglePose code and model card are Apache-2.0. The text of the MoveNet MultiPose card carries no licence line, Ultralytics YOLO is AGPL-3.0 unless you buy an Enterprise License, and OpenPose is for noncommercial research only. Pose estimation model licenses reads each one.

What we verified, and where#

Is switching easy?#

Leaving Sency's Branded Kit means replacing a whole UI as well as the tracking. Leaving the Custom Kit is closer to a model swap, because your app already owns the camera, rendering and results, but assessments, feedback and plans that Sency computed become your code unless the new vendor supplies them. Run any candidate on your own recorded exercises first; how to evaluate motion SDKs sets out a fair protocol.