OpenSky Network Review

What OpenSky Network Is

OpenSky Network uses the same concept as Flightradar24 and ADS-B Exchange. Volunteers run ground receivers that pick up 1090 MHz ADS-B signals from planes.

The focus here is on researchers. The interface is basic, but the tools are technical. A free REST API with years of historical flight data is available. Raw ADS-B state vectors are available, and queries can be made in bulk with SQL.

The historical archive sets OpenSky apart. Flightradar24 charges $99.99/month for API access to historical data. OpenSky provides it for free.

Coverage is best in Europe, North America. The volunteer receivers are concentrated there. Elsewhere, gaps are expected, in Europe, North America, and other regions, such as Asia, Africa, South America; however specifically Europe and North America.

OpenSky Network uses the same concept as Flightradar24 and ADS-B Exchange. Volunteers run ground receivers that pick up 1090 MHz ADS-B signals from planes.

The focus here is on researchers. The interface is basic, but the tools are technical. A free REST API with years of historical flight data is available. Raw ADS-B state vectors are available, and queries can be made in bulk with SQL.

The historical archive sets OpenSky apart. Flightradar24 charges $99.99/month for API access to historical data. OpenSky provides it for free.

The coverage areas include Europe and North America. These areas have many volunteer receivers. Other areas have gaps.

What It's Good For

Historical Flight Path Reconstruction

OpenSky excels at historical flight path reconstruction. Want to know where aircraft N12345 was on March 4th, 2023? OpenSky provides that data for free, often spanning years, with a simple API call. This is the main advantage over other free options.

Bulk Aircraft Movement Analysis

Bulk analysis is another strong use case. You can pull all departures from a specific airport within a defined time frame, or query every flight associated with a given ICAO hex code over months. Trino SQL access handles these bulk queries. FR24's API pricing often exceeds budgets for independent investigators.

Integration and Workflow

OpenSky works seamlessly with Python through the pyopensky library. Output feeds directly into pandas dataframes. Data cleaning, filtering, and visualization fit into a standard analytical workflow. No manual CSV exports are needed.

Verifying Commercial Flight Claims

Verifying commercial flight claims is straightforward. Pull the aircraft's state vectors for a given day. Confirm the route and timing. No subscription is required.

Budget-Friendly Option

For those on a budget, OpenSky serves as a viable fallback. It delivers when FR24's Business tier is too expensive. Rate limits exist, but are manageable for most investigative queries.

Getting Started

OpenSky Network API

To use the OpenSky Network API, you need to register at opensky-network.org. Unregistered users hit API rate limits quickly. Registration is free.

Current State Vectors

The REST API provides current state vectors. You can access all current state vectors with a GET request to https://opensky-network.org/api/states/all.

If you want information on a specific plane, you can add the ICAO hex code to the request. For example, https://opensky-network.org/api/states/all?icao24=a835af.

Historical Flight Data

The API also provides historical flight data. To retrieve flight history, use a GET request like https://opensky-network.org/api/flights/aircraft?icao24=a835af&begin=1677628800&end=1677715200. The timestamps are in Unix epoch time, and the begin and end parameters set your time window.

Python Setup

Python users can install the library with pip install pyopensky. Authenticate with your OpenSky credentials. The library handles REST calls and returns pandas DataFrames.

Bulk Historical Queries

For heavy lifting and access to full historical data, use Trino. This requires more setup but is worth it. A local Trino client is required.

OpenSky API Endpoints

Rate limits apply to all endpoints. Free accounts get more requests than anonymous users. You can check the limits on the OpenSky Network API documentation website at opensky-network.org/apidoc.

Pricing

OpenSky Network is free, with no paid tier available.

To access Trino, you need an application. It is not auto-approved on registration. Researchers and investigators who have a solid use case are typically approved.

Limitations

OpenSky's web map works, but it's bare-bones. The research interface is not for the general public. For clean visuals or quick aircraft lookups without coding, FR24's still your best bet.

Meaningful history from OpenSky demands API calls or SQL queries. Users who don't code face a steep learning curve. A Python library helps coders, but doesn't eliminate the hassle.

Data gaps exist outside Europe and North America. Investigations in these regions will hit roadblocks. Don't assume an aircraft wasn't flying just because it's not in the data.

Some aircraft are blocked. OpenSky respects opt-out requests, so some planes on ADS-B Exchange won't show up here. ADS-B Exchange lists aircraft, but OpenSky doesn't.

State vectors update every 10-15 seconds. This update frequency is good enough for investigations, but not ideal for real-time monitoring.

Trino access requires a local client setup. The setup is documented, but it adds at least an hour of prep before you can query.

Alternatives

Flightradar24 has a clean UI and mobile app. The Gold plan costs $7.99/mo and offers 365-day history. However, historical API access costs $99.99/mo. LADD aircraft are not shown.

ADS-B Exchange is unfiltered, which is its strength. However, a custom API deal is required for data older than 7 days. There is no public pricing. It surpasses OpenSky on openness but falls short on transparency. ADS-B Exchange provides data on various aircraft, including military, private, and commercial planes.

FlightAware dominates US commercial aviation with deep FAA data integration. API pricing is clear. However, private aircraft history is not its strong suit. FlightAware offers data on commercial aircraft, such as Delta, American Airlines, and United.

The FAA Aircraft Registry is not a tracker. It is the go-to source for US aircraft information. It is free and no account is needed. You can confirm an N-number's owner and operator.

Bottom Line

OpenSky offers free API access to years of flight data—that's its niche. You can't get historical flight data elsewhere for free.

Need to know where an aircraft was two years ago? OpenSky is your option if FR24's Business tier is out of budget.

The catch: it's for coders. You'll make REST calls or write Python scripts. OpenSky's archive is unmatched. The cost is nothing.

See Also

Best ADS-B Software, ADS-B Setup Guide

Further Reading

• OpenSky Network official site
• OpenSky REST API documentation