Comparison

HydroCrowd vs SDG Master

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

Head to head
About

HydroCrowd

Features
Read full description

HydroCrowd is a research project of the Justus Liebig University Giessen, which investigates the potential of participatory monitoring to increase the availability of hydro-climatic data for sustainable water management, especially in remote areas in the global south. The project will test different approaches to engage volunteers through the implementation and evaluation of a participatory hydro-climatic monitoring program in selected mountain regions in Ecuador, Honduras and Tanzania. Furthermore, it will demonstrate how the data collected by the volunteers can be used in hydrological modelling and, therefore, improve the prediction of climate change impact on water resources in data-scarce regions. The project outputs can be used to guide the development of future participatory monitoring programs and stimulate upscaling of the approach to other regions to address the lack of hydro-climatic data for evidence-based decision making and sustainable water management. Volunteers participate by reporting measurements from easy-to-use instruments at weather and water stations installed in the project areas in Ecuador, Honduras and Tanzania. These measurements include rainfall, air temperature and humidity, as well as the water level and turbidity of rivers and streams. To evaluate the quality of the data, the data will be compared with automated reference measurements at selected sites. These are then systematically examined and tested for their suitability for modeling. This app enables easy submission of data by the volunteers and provides instructions on how to collect data. Furthermore, users can view the data previously submitted by other volunteers. As the remote study areas have limited network access, it is recommended to download the map of your region and the locations of the stations before going to any of the HydroCrowd stations. In addition to reporting measurements from the HydroCrowd stations, volunteers also have the opportunity to create spots to record their own rainfall data, and to report weather events using β€˜photo notes’. The HydroCrowd Citizen Science App is running on the SPOTTERON Platform.

About

SDG Master

Features
Read full description

SDG Master is a mobile game developed under the Erasmus+ partnership in adult education Sustainability Coaches, led by VNB e.V. (Germany), alongside Eco-Logic (North Macedonia), Synthesis (Cyprus), and CSCI (Italy), aiming to equip trainers and community educators with the skills to become "Sustainability Coaches." These coaches will guide and inspire communities to take meaningful local actions with a global perspective, fostering sustainable practices that benefit society on a larger scale.

Screenshots

HydroCrowd4 screens
SDG Master3 screens

Verdict

The call

HydroCrowd and SDG Master are too close to call on the numbers: across 6 compared parameters β€” price, update cadence, ads and in-app purchases among them β€” neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

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

CostPrice Β· In-app purchases Β· Ads Β· Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Both ship on a similar rhythm, roughly every 3 months. The most recent releases landed on September 28, 2026 and October 8, 2026 respectively.

ScorecardNo meaningful differences
HydroCrowd versus SDG Master: the parameters behind the verdict, then further details
ParameterHydroCrowdSDG Master
PriceFreeFree
Update frequencyEvery 3 monthsEvery 3 months
AdsNoNo
In-app purchasesNoNo
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS12.0 β€” better13.0
Further details β€” not scored
Size61 MB260 MB
Age rating4+17+
DeveloperSPOTTERON GmbhIlija Rushkovski

In-app purchases

None

HydroCrowd

No in-app purchases

None

SDG Master

No in-app purchases

Questions

Is HydroCrowd free?
HydroCrowd is free to download, with no in-app purchases.
Is SDG Master free?
SDG Master is free to download, with no in-app purchases.
Do HydroCrowd or SDG Master have ads?
Neither HydroCrowd nor SDG Master shows ads.
Which is updated more often, HydroCrowd or SDG Master?
HydroCrowd ships an update every 3 months, and SDG Master every 3 months. Most recently, HydroCrowd was updated on September 28, 2026 and SDG Master on October 8, 2026.

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