Comparison

Line vs Inertia Pro

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Line

This app allows users to create, save, and share digital sketches and doodles. It connects to a robot drawing arm to bring digital creations to life on paper, offering tools for scaling, rotating, and combining drawings. Users can also trace photos and share their artwork in a cloud-based sketchbook.

Highlights
  • Create, save, and share digital sketches
  • Draw with finger, Apple Pencil, or stylus
  • Scale, rotate, and combine drawings
  • Trace photos with tracing mode
  • Cloud sketchbooks for sharing
  • Code control with Scratch, Python, Javascript
Features
Read full description

Create, save and share and publish your sketches and doodles with the Line-us app. If you have Line-us, the internet connected Robot Drawing Arm, have fun drawing them with a real pen on paper. Draw and write with your finger, an Apple pencil or a stylus. The app has tools to scale, rotate, or even combine multiple drawings to create fun new doodles. There is also a tracing mode that allows you to use a photo as a background so anyone can get started with Line-us. Create sketchbooks in the Line-us Cloud publish and share them with other users. Send a sketch to say Hello or get together with other creators around the world and share your drawings, doodles and artwork. Control Line-us with your own code. Use Scratch, Python, Javascript, Processing or a host of other languages to get Line-us to to develop your own Line-us programs. We hope you love sketching with Line-us as much as we do.

About

Inertia Pro

This app allows users to force any content on any website, including social media posts, products, and text. It's integrated into a web browser for seamless use during performances. Additional paid features enable editing text and using the app on borrowed phones.

Highlights
  • Force any Instagram photo or video
  • Force specific items on eBay or Amazon
  • Force Netflix movies or news headlines
  • Edit text on any website
  • Use on borrowed phones with Momentum add-on
  • Remote performance capabilities via Xeno Sites
Features
Read full description

Inertia Pro is a completely new forcing app that relies on a diabolical new principle. Inertia Pro lets you force *anything* on *any website*... whilst the spectator is looking at the phone. It’s built in to a web browser, allowing you to use it to force pretty much anything, such as: • An Instagram photo or video on ANY profile. • A specific item for sale on eBay. • Any Netflix movie. • A product from Amazon. • A line of text or single word on a news website. • Any photo from Google Images. • ...and so much more! (Note: The page used is completely genuine - this will work on ANY website the spectator chooses, and in ANY language!) “Marc is without doubt the single greatest mentalism app creator I know. From design to execution, his apps are absolutely flawless. Inertia Pro is a prime example of why I trust in his work so implicitly, it is jaw droppingly good and represents one of the most cutting-edge mentalism releases to date!” - Michael Murray Plus, with Inertia Pro's new Edit Mode (paid feature), you can now edit the text on any site to ensure your force is included. ALSO - Inertia Pro: Momentum (paid feature) now also lets you use Inertia Pro on a borrowed phone. With multiple pairing methods available and a redirect process, Momentum is an extra purchase within Inertia Pro that will let you perform the same effect using a borrowed phone. Furthermore: WikiTest Pro Tools users can even use further integrations between Inertia Pro: Momentum. If you have Xeno, you can use your own Xeno Sites with Inertia Pro, or use any of the public Xeno Sites available in the gallery. And... you can perform Inertia Pro with any Xeno Site remotely! This can all happen on the spectator's device, without you touching it. Perfect for Zoom shows or long-distance performances! The Jerx wrote this about Inertia Pro: “You know those phone forces where you would hold the phone upside down and have them scroll blindly and whatever picture or item they landed on would be forced (usually because their scrolling wasn’t doing anything)? Well, this app allows you to do that type of force face-up while the spectator looks at the phone. It’s so good and *feels* exactly like it should.” - Andy @ The Jerx --- Inertia Pro is for entertainment purposes only, designed for professional performers. This app does not provide true mind reading abilities or anything similar. Please get in touch to discuss TV or video performance rights.

Screenshots

Line2 screens
Inertia Pro3 screens

Verdict

The call

The clearest difference is review sentiment: Inertia Pro at 100% against Line's 25%. Inertia Pro also leads on rating (4.9 vs 3.1) and update cadence (weekly vs every 2 months). Line's advantage is price (Free vs $69.99) and in-app purchases (none vs 2). On ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Line is free to download; Inertia Pro costs $69.99 up front. Inertia Pro sells 2 one-off in-app purchases. Line asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Inertia Pro holds the better App Store score, 4.9 against 3.1. Both are backed by a comparable volume of ratings — 7 and 31 respectively. Written reviews point the same way: 25% of Line's written reviews are positive against 100% of Inertia Pro's.

UpkeepUpdate frequency

Line ships an update every 2 months, Inertia Pro weekly. The most recent releases landed on November 6, 2026 and November 7, 2026 respectively.

Scorecard9 real differences · 2 level
Line versus Inertia Pro: the parameters behind the verdict, then further details
ParameterLineInertia Pro
PriceFree — better$69.99
Rating3.1 (7 ratings)4.9 (31 ratings) — better
Positive reviews25.0% of reviews100.0% of reviews — better
Number of ratings731 — better
Update frequencyEvery 2 monthsWeekly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterPaid
Best chart rank—#84 — better
DevicesiPhone, iPad, iPod — betteriPhone, Apple Watch
Requires iOS8.0 — better16.6
Further details — not scored
Size30 MB14 MB
Age rating12+17+
DeveloperDRP London LimitedMarc Kerstein

Customer experience

Line

All ratings7 ratings
Positive42.9%
Neutral14.3%
Negative42.9%
Written reviews4 reviews
Positive25.0%
Neutral50.0%
Negative25.0%

Inertia Pro

All ratings31 ratings
Positive96.8%
Neutral3.2%
Negative0.0%
Written reviews8 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Line

No in-app purchases

2 purchases

Inertia Pro

One-time2
  • Edit Mode$12.99
  • Momentum$59.99

Questions

Is Line free?
Line is free to download, with no in-app purchases.
Is Inertia Pro free?
Inertia Pro costs $69.99, and also offers in-app purchases.
Which has better reviews, Line or Inertia Pro?
Inertia Pro is rated higher. Line averages 3.1 out of 5 from 7 ratings, while Inertia Pro averages 4.9 from 31 ratings.
Do Line or Inertia Pro have ads?
Neither Line nor Inertia Pro shows ads.
Which is updated more often, Line or Inertia Pro?
Line ships an update every 2 months, and Inertia Pro weekly. Most recently, Line was updated on November 6, 2026 and Inertia Pro on November 7, 2026.

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