# VPD Tool vs DomainDig

The clearest difference is price: DomainDig at Free against VPD Tool's $0.49. DomainDig also leads on update cadence (every 2 weeks vs every 2 months) and ratings volume (3 vs 1). On rating, review sentiment, ads and in-app purchases there is nothing between them.

DomainDig is free to download; VPD Tool costs $0.49 up front. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for VPD Tool against 5.0 for DomainDig. Both are backed by a comparable volume of ratings — 1 and 3 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

VPD Tool ships an update every 2 months, DomainDig every 2 weeks. The most recent releases landed on October 18, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | VPD Tool | DomainDig |
| --- | --- | --- |
| Price | $0.49 | **Free** |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/vpd-tool/id6751213834/reviews) | [5.0 (3 ratings)](https://appshunter.io/ios/app/domaindig/id6760368004/reviews) |
| Number of ratings | 1 | **3** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 2 weeks** |
| Monetization | Paid | **Free** |
| Size | 2 MB | 8 MB |
| Requires iOS | 18.5 | **17.6** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nicholas Hwang](https://appshunter.io/developer/1802240669) | [Christian Cleberg](https://appshunter.io/developer/1883866326) |

## What reviewers say

### VPD Tool

[App page](https://appshunter.io/ios/app/vpd-tool/id6751213834)

This utility app helps growers understand Vapor Pressure Deficit (VPD) for optimal plant growth. It features an interactive heatmap and stage presets to guide environmental adjustments. Calculations are performed on-device for privacy.

**Highlights:** Interactive VPD heatmap, Stage-specific VPD ranges, Leaf and Air VPD calculation, Home and Lock Screen widgets, On-device calculations, CSV log export

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### DomainDig

[App page](https://appshunter.io/ios/app/domaindig/id6760368004)

Inspect domains and servers with comprehensive diagnostics. Quickly check DNS records, SSL certificates, email security, HTTP headers, and network reachability. Includes IP geolocation and a history of your lookups.

**Highlights:** DNS record lookup (A, MX, NS, TXT, CNAME), SSL/TLS certificate inspection, Email security record parsing (SPF, DMARC, DKIM), HTTP header analysis, Redirect chain tracing, Port scanning and latency measurement, IP geolocation with map view

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is VPD Tool free?

VPD Tool costs $0.49, with no in-app purchases.

### Is DomainDig free?

DomainDig is free to download, with no in-app purchases.

### Which has better reviews, VPD Tool or DomainDig?

VPD Tool and DomainDig are both rated 5.0 out of 5 on the App Store, from 1 and 3 ratings respectively.

### Do VPD Tool or DomainDig have ads?

Neither VPD Tool nor DomainDig shows ads.

### Which is updated more often, VPD Tool or DomainDig?

VPD Tool ships an update every 2 months, and DomainDig every 2 weeks. Most recently, VPD Tool was updated on October 18, 2026 and DomainDig on October 25, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*