Curve vs Nullify
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Curve
This app performs regression analysis using the method of least squares to fit various equations to your data. The free version offers straight-line fitting, with additional equation types available via an in-app purchase. It's designed for users needing to analyze and model data sets.
- Least squares regression analysis
- Multiple equation fitting options
- Data set analysis
- Free straight-line fitting
- In-app purchase for advanced equations
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'CurveFit' uses regression analysis by the method of least squares to find best fit for a set of data to a selected equation. The curve-fitting technique used in this app is based on regression analysis by the method of least squares. The free version fits a straight line through a data-set using least squares analysis. One In-App purchase is required to fit the other equations to the data set: Straight Line : Y = C0 + C1*X (free) Power Curve : Y = C0 + X^C1 Exponential I : Y = C0 * EXP(C1*X) Exponential II : Y = C0 * X * EXP(C1*X) Hyperbolic : Y = (C0 + C1*X)/(1 - C2*X) Square Root : Y = C0 + C1*SQRT(X) Polynomial : Y = C0 + C1*X + --- + CN*X^N Exponential Poly : Y = C0 * EXP(C1*X + --- + Natural Log : Y = C0 + C1*(LN(X)) + --- + Reciprocal : Y = C0 + C1/X + --- + CN/X^N Most literature deals with least squares analysis for straight lines, 2nd degree polynomials, and functions that can be linearized. The input-data is transformed into a format that the can be put into linear forms with undetermined constants. These types of equations are applicable for least-squares regression. The regression routine is needed for determining values for the set of unknown quantities C1, C2,- - - ,Cm in the equation: Y = C1 x F1(X) + C2 x F2(X) + - - - + Cm x Fm(X) The constants are determined to minimize the sum of squares of the differences between the measured values (Y1, Y2, - - - , Yn) and the predicted equation Yc = F(X) which is found by curve-fitting the given data. The principle of least squares is to find the values for the unknowns C1 through Cm that will minimize the sum of the squares of the residuals: n ∑(ri) = r12 + r22 + - - - + rn2 = minimum i=1 This is done by letting the derivative of the above equation equal zero. Thereby there will be generated as many algebraic equations as given data points, and the number of equations will be larger than unknowns.
Nullify
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Nullify uses AI to automatically detect and redact personal information from your documents and photos. Upload any image, let the AI scan for personal data — names, ID numbers, phone numbers, emails, IBANs, signatures, and more — then review, confirm, and save your redacted document in seconds. Perfect for: • Sharing IDs, passports, or driver's licenses safely • Sending documents without exposing private details • Complying with privacy regulations like GDPR • AI-Powered Detection — Finds PII automatically with high accuracy • Review & Select — See exactly what gets redacted before you commit • Manual Zones — Draw custom areas for anything the AI misses • Instant Results — Redacted document ready in seconds • Privacy First — Your data stays on your device Take control of your privacy. Nullify protects it. A one-time purchase is required to redact each document. Privacy Policy: https://nullify.savaskoc.de/privacy Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is price: Nullify at Free against Curve's $0.99. Nullify also leads on update cadence (every 3 months vs every 42 months). Curve's advantage is device support (3 vs 1) and iOS requirement (15.6 vs 18.0). On ads and in-app purchases 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
Nullify is free to download; Curve costs $0.99 up front. Curve sells 1 one-off in-app purchase and Nullify sells 3 in-app purchases, starting at $3.99 per 7 days. Whichever you choose, the download price is not the number that matters.
Curve ships an update every 42 months, Nullify every 3 months. The most recent releases landed on October 24, 2026 and October 28, 2026 respectively.
| Parameter | Curve | Nullify |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 5.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 42 months | Every 3 months — better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.6 — better | 18.0 |
| Further details — not scored | ||
| Size | 1 MB | 11 MB |
| Age rating | 12+ | 4+ |
| Developer | Bjarne Berge | SAVAS KOC |
In-app purchases
Curve
- Curve-Fit$2.99
Nullify
- Weekly3 Days trial$3.997 Days
- Monthly3 Days trial$9.991 Month
- Annual3 Days trial$39.991 Year









