Short answer: PlotJuggler and Foxglove solve the same problem — understanding recorded robotics data — from opposite ends. PlotJuggler is a free, open-source (MPL-2.0), offline desktop application: you open ROS bags, MCAP files, CSV exports and ULog flight logs locally, drag signals onto plots, and pay nothing, ever, with no account. Foxglove is a commercial data platform — desktop, web and cloud — built for teams that need recordings shared, stored and reviewed together; its Free tier covers 3 developer seats and 10 GB of storage, and Pro starts at $20/month plus usage. Individual engineers analysing their own logs usually belong on PlotJuggler; teams that have outgrown passing files around are who Foxglove’s pricing is buying. This comparison is part of our Alternatives & Comparisons hub.
The evidence table
| Criterion | PlotJuggler | Foxglove |
|---|---|---|
| Cost | Free and open-source (MPL-2.0). No account, no tiers, no usage metering. | Free tier: 3 dev seats / 10 GB storage / 5 devices. Pro from $20/mo plus usage (e.g. storage beyond included amounts). Academic use is free. (Foxglove’s published pricing.) |
| Deployment | Offline desktop application (Windows, Linux; PJ3 also via ROS packages and snap). Your data never leaves the machine unless you send it. | Desktop + web + cloud data platform. The cloud layer is the point: recordings are uploaded, stored and shared with the team. |
| Formats | ROS 1/ROS 2 bags (PJ3 via the ROS plugins), MCAP (native in PJ4), CSV, PX4 ULog, Parquet and more in PJ4; live streaming over ROS topics, MQTT, WebSocket, ZMQ and UDP. | Natively supports MCAP, ROS 1 and ROS 2, plus Protobuf/JSON/FlatBuffers via WebSocket. (Foxglove’s published format support.) |
| Team features | Individual tool. Collaboration means sharing files and saved layouts; there is no hosted workspace, no shared library, no seat management. | Built for teams: shared cloud storage, multiple seats, devices and a platform designed around reviewing the same recordings together. |
| Analysis style | Drag-and-drop plotting, layouts, per-curve (PJ3) and per-dataset (PJ4) time offsets, built-in transforms, Lua custom functions (Python too in PJ4), XY plots, and in PJ4 time-synced video and 3D. | Panel-based visualisation in a browser-grade interface, oriented around exploring shared recordings and live connections as a team. |
Where PlotJuggler genuinely wins
Start with the arithmetic: for a solo engineer or a small team whose workflow is “record a bag, open the bag, find the problem”, PlotJuggler costs nothing and asks for nothing — no account, no upload, no seat count. That matters beyond thrift. Flight-test and field data is often sensitive, export-controlled or simply too large to upload comfortably; an offline tool that reads the file where it sits removes a whole category of friction and compliance questions. PlotJuggler is also a deeper plotting instrument in the specific ways daily debugging rewards: saved layouts you reload against the next recording, time offsets for aligning runs, custom transforms computed in Lua (and Python in PlotJuggler 4), and a ULog workflow so established that the official PX4 documentation recommends PlotJuggler for log analysis. For PX4 and ArduPilot users, our drone flight log roundup covers that ground in full.
Where Foxglove genuinely wins
Foxglove wins the moment the problem stops being plotting and becomes logistics. If recordings live on five laptops, if a reviewer in another timezone needs the same view you had, if “which bag was that?” is a weekly question, a hosted platform with shared storage, seats and devices is not a luxury — it is the tool shaped like your problem, and its Free tier (3 seats, 10 GB) is a legitimate way to test whether your team is that team before paying the $20/month Pro starting point. Foxglove is also the more natural home for organisations that want a vendor: a commercial product with tiers and support is a procurement answer an open-source desktop app, however good, does not provide. Our PlotJuggler Alternatives guide is written for exactly the teams weighing this move.
Verdict by user type
| You are… | Choose | Why |
|---|---|---|
| A solo ROS or drone engineer analysing your own bags and logs | PlotJuggler | Free, offline, deep plotting, layouts and transforms; nothing to upload or administer |
| A small team passing recordings around by hand, starting to feel the pain | Try Foxglove Free alongside PlotJuggler | 3 seats / 10 GB costs nothing and tells you honestly whether a platform fixes your actual bottleneck |
| A team that needs shared, searchable, hosted recordings and device fleets | Foxglove Pro | That is precisely what the paid tiers sell; PlotJuggler has no equivalent because it is a desktop application |
| Working with sensitive data that cannot leave your machines | PlotJuggler | Fully offline by design; the file is analysed where it sits |
| A student | Either — both are free to start | Foxglove is free for academic use; PlotJuggler is free for everyone. Learn whichever your lab already uses |
Two honest footnotes. First, these tools coexist in plenty of real teams: PlotJuggler for deep local analysis, a platform for sharing — the choice is about your default, not a vow. Second, Foxglove has no affiliate program and nothing in this verdict is sponsored; the same “choose by job” logic runs through the rest of this section, including PlotJuggler vs Rerun and the Best ROS 2 Data Visualization Tools roundup. Whichever you pick, the files and installers for PlotJuggler are on our Download page.
Keep learning
If this comparison sent you back to sharpen the ROS 2 skills both tools assume, structured courses are the fastest route: ROS courses on Coursera
(affiliate links)