Watki vs GT Graph
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Watki
This app provides offline access to detailed descriptions of all OpenGL ES commands and functions from the official Khronos Group website. It's designed to help developers easily reference graphics API information, even for beginners.
- Complete OpenGL ES 3.2 command descriptions
- Information from official Khronos Group website
- Offline access
- Systematic function listing
- Search bar and index
- Landscape mode support
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Watki is an offline field guide to open graphics, compute and XR standards. Every call, built-in and type, with what it does, what it takes and where it fits, set in a quiet black-and-white reader that works without a connection. WHAT'S INSIDE 21 volumes and more than 12,000 entries, including: • Vulkan 1.4 and Vulkan SC 1.0, with extensions • OpenGL ES 2.0 to 3.2, OpenGL 4.6 core and OpenGL SC 2.0 • EGL 1.5 and WebGL 1.0 and 2.0, with extensions • OpenCL 3.0 and OpenCL C, SYCL 2020 and SPIR-V 1.6 • OpenXR 1.1, OpenVX 1.3.1, OpenVG 1.1 and ANARI 1.1 • The Slang core module • glTF 2.0, KTX 2.0, COLLADA 1.5 and NNEF 1.0.5 • Short overviews of machine learning and safety-critical work HOW IT READS • Each volume opens to its sections; each section lists its entries in groups you can jump between. • Entries show the signature, parameters, return values and the version or extension that added them. • Search across every volume at once. • Keep the entries you use most and come back to recent ones. • See how much of each volume you have read. MADE TO BE LOOKED AT A slow mist drifts behind the pages and changes with the time of day. You can thicken it, slow it, freeze it or give it a new pattern. In the darkroom you can develop any photo as a 1-bit print and save it. PRIVATE AND OFFLINE Everything ships inside the app. No account, no ads, no tracking and no data collected. SOURCES The reference text is generated from the published registries, headers and reference pages of each standard, under their licences. Full credits and licence details are in the app. Watki is an independent reader and is not affiliated with or endorsed by The Khronos Group or any other standards body. Vulkan, OpenGL ES, OpenGL SC, EGL, WebGL, OpenCL, SYCL, SPIR-V, OpenXR, OpenVX, OpenVG, ANARI, glTF, KTX, COLLADA, NNEF and Khronos are trademarks or registered trademarks of The Khronos Group Inc. OpenGL is a registered trademark of Hewlett Packard Enterprise, used under licence by Khronos. Slang is a trademark of its respective owner. All other names are the property of their owners and are used only to identify the standards described.
GT Graph
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GT Graph transforms your device into a powerful mathematical visualization tool. Plot equations, explore calculus concepts, and bring mathematics to life with stunning interactive graphs. PLOT ANY EQUATION - Cartesian functions - Polar curves - Parametric equations - Implicit equations - Inequalities with shaded regions INTUITIVE INPUT Type equations naturally with implicit multiplication support. Write 2x instead of 2*x, or 2sin(x) instead of 2*sin(x). GT Graph understands mathematical notation the way you write it. COMPREHENSIVE FUNCTION LIBRARY - Trigonometric: sin, cos, tan, sec, csc, cot - Inverse trigonometric: asin, acos, atan - Hyperbolic: sinh, cosh, tanh - Exponential and logarithmic: exp, ln, log, log2 - Power functions: sqrt, cbrt, abs - Constants: pi, e, phi (golden ratio) MULTIPLE GRID TYPES - Standard Cartesian grid - Trigonometric grid with pi-labeled axes - Polar coordinate grid with radial lines - Logarithmic scale grid CALCULUS TOOLS - Calculate derivatives at any point - Compute definite integrals with visual shading - Find zeros (roots) of functions - Locate local minima and maxima - Generate value tables INTERACTIVE EXPLORATION - Pinch to zoom, drag to pan - Tap to show tangent lines - Crosshair cursor displays coordinates - Plot multiple equations simultaneously - Color-coded graphs for easy identification SAVE AND SHARE - Save your work as .gtgraph files - Export and share with colleagues - Equation history saves your last 25 entries - Settings persist between sessions Perfect for: - Students learning algebra, trigonometry, and calculus - Teachers creating visual demonstrations - Engineers and scientists visualizing data - Anyone curious about mathematical beauty GT Graph combines the power of professional graphing software with the elegance of modern design. Start plotting today!
Screenshots
Verdict
The clearest difference is in-app purchases: Watki at none against GT Graph's 1. GT Graph's advantage is update cadence (every 8 days vs every 134 months). On price, ads, device support and iOS requirement 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
Both are free to download. GT Graph sells 1 one-off in-app purchase. Watki asks for nothing beyond the download.
Watki ships an update every 134 months, GT Graph every 8 days. The most recent releases landed on November 11, 2026 and November 9, 2026 respectively.
| Parameter | Watki | GT Graph |
|---|---|---|
| Price | Free | Free |
| Rating | 3.0 (3 ratings) — better | — |
| Positive reviews | 66.7% of reviews | — |
| Number of ratings | 3 — better | — |
| Update frequency | Every 134 months | Every 8 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | — |
| Devices | iPhone, iPad | iPhone, iPad, Mac — better |
| Requires iOS | 18.0 | 18.0 |
| Further details — not scored | ||
| Size | 7 MB | 1 MB |
| Age rating | 4+ | 4+ |
| Developer | Saumya Lahera | Gennaro Eduardo Tangari |
In-app purchases
Watki
No in-app purchases
GT Graph
- GT Graph In-App Purchase$0.99









