Pasteboard Viewer: A Read-Only Inspector for macOS Pasteboards
📋 Inspect the system pasteboards on macOS
At a glance
- What is it?
- Pasteboard Viewer is a Swift developer utility that shows what your app actually writes to NSPasteboard and UIPasteboard, refreshing live and previewing text, RTF, images and Quick Look types. It is not a clipboard manager, and its minimum OS requirements are the first thing to check.
- Who is it for?
- Adopt Pasteboard Viewer if you write Swift or Objective-C code that puts data on NSPasteboard or UIPasteboard and you need to see the exact type identifiers your code produces, including the legacy types the app hides. Skip it if you want clipboard history, cross-device sync or a non-programmer clipboard tool; the README states plainly that it is not a clipboard manager.
- Can I use it commercially?
- Yes. MIT is a permissive licence: you can use, modify and sell software built on it, as long as you keep its copyright and licence notices.
- Is it still maintained?
- Yes. The repository last received commits 169 days ago.
- What is it written in?
- Mainly Swift, according to GitHub's language statistics.
Answers come from the project's GitHub data, last synced on September 15, 2026, and from our analysis. They are not legal advice.
DEEP OPEN-SOURCE ANALYSIS
The debugging gap Pasteboard Viewer fills
When an app copies something, the pasteboard holds more than the string or image the user sees. NSPasteboard and UIPasteboard carry a set of typed representations, and a receiving app picks the one it understands. If you write the wrong type identifier, or write a type the receiving app never reads, the paste fails silently. There is no exception, no console warning, just a paste that does nothing. The README frames the tool's purpose around exactly this: it is useful "to ensure your app is putting the correct data on NSPasteboard or UIPasteboard". The audience is narrow and stated: developers. The README says if you are not a programmer, you probably do not want this app, and it explicitly disclaims being a clipboard manager. That disclaimer matters, because the name invites the wrong expectation. A clipboard manager keeps history and lets you paste old items. This app inspects the current state of the system pasteboards and nothing more.
What the window shows and how it refreshes
The app reads the pasteboard contents and refreshes them live, so a copy performed in another app appears without you switching back and pressing anything. Each pasteboard item is listed with its type identifiers, and the sidebar is where you work: right-clicking an item on macOS, or long-tapping on non-macOS, copies that type identifier to the clipboard. That single interaction is the most practical part of the tool, since the identifier string is what you paste into your own code. Preview support covers text, RTF, images, and anything with a Quick Look preview, which means a custom type with a registered Quick Look generator can be inspected without writing a decoder. Navigation is keyboard-driven: the README states that the up and down arrow keys switch between pasteboard items. On macOS the window can be pinned above other windows through "Stay in Front" in the "Window" menu, which is the difference between a usable inspector and one that disappears the moment you click into your editor to compare output.
The type-hiding behaviour is the design decision to understand
Pasteboard Viewer hides obsolete system pasteboard types that have modern equivalents, and the README names examples: CorePasteboardFlavorType, NSStringPboardType, NSFilenamesPboardType. This is a deliberate filter, and it cuts both ways. For everyday work it removes noise, because modern macOS pasteboards often carry a long tail of legacy representations that no current code should be reading. But if you are debugging an older code path, or verifying compatibility with a receiver that still asks for one of those legacy types, the type you care about may not appear in the list at all. The README does not describe a toggle for showing hidden types, so the safest reading is that the filter is not optional. Treat this as the tool's central trade-off: a cleaner default view in exchange for a blind spot exactly where legacy interop bugs live.
Getting it running, and the version cliff
There is no build step described in the README. Distribution is through the App Store, and the README states the current build requires a minimum of macOS 26, iOS 26, or visionOS 26. That is a high floor, and it is the first thing to check before anything else. If you are on an older system, the README links direct release zips: 2.11.0 for macOS 15+, 2.8.0 for macOS 14+, 2.5.1 for macOS 13+, 2.4.1 for macOS 12+, 2.2.2 for macOS 11+, and 1.5.1 for macOS 10.15+. For users who cannot access the App Store, the README offers a separate non-App Store build, currently Pasteboard Viewer 2.12.0 for macOS 26+, hosted on Dropbox. The README is explicit that this version will not receive automatic updates and that the author updates it about once a year. That is a real constraint, not a footnote: if you take the non-App Store path, you are choosing a snapshot. The repository is MIT licensed and the source is on GitHub, so building from source is available to anyone willing to work with the project's Swift toolchain and Xcode, though the README itself does not document that path.
Where it stops being the right tool
The clearest failure mode is expectation mismatch. If you install this hoping to recover something you copied ten minutes ago, it cannot help, because it does not keep history. The README states it is not a clipboard manager and that non-programmers probably do not want it. A second limitation is platform scope. The description says it inspects the system pasteboards on macOS, and the download section lists macOS, iOS and visionOS requirements, but the README's usage instructions are macOS-centric: the right-click versus long-tap note is the only gesture guidance offered for non-macOS, and "Stay in Front" is described as a macOS window menu item. Anyone expecting the same depth of documented workflow on iOS or visionOS should verify behaviour themselves rather than assume parity. A third limitation is that the app inspects, it does not record or diff. There is no described way to compare two pasteboard states or to export a snapshot, so verification is visual and manual.
How it differs from a clipboard manager
The obvious alternative category is the clipboard manager, and the difference is architectural rather than cosmetic. A clipboard manager subscribes to pasteboard changes, stores each item in a persistent history, and gives you a UI to search and re-paste old entries. Its data flow is copy, store, retrieve. Pasteboard Viewer's data flow is copy, display, discard. It holds no history and offers no paste-back mechanism, which is why the README's disclaimer is not modesty but a specification. The practical consequence: a clipboard manager will tell you what you copied earlier, while this app tells you what types your copy operation produced right now. If your bug is "the paste target receives nothing", you want the type list, not the history. If your bug is "I lost the thing I copied", you want the opposite tool, and Pasteboard Viewer will not be it.
Maintenance, licensing and what to verify
The repository is active rather than archived, with releases at v2.12.0, v2.11.0 and v2.10.1. The spacing between those releases is uneven, and the README's own note about the non-App Store build being refreshed about once a year suggests the author treats the project as a maintained utility rather than a fast-moving product. The licence is MIT, which permits reuse and modification subject to the licence terms; that is a statement about the licence text, not legal advice, and anyone redistributing the app or its code should read the licence themselves. There is no stated localization plan, and the FAQ answers the localization question with a flat no. The absence of a documented build procedure in the README means that source-based adoption carries more setup work than the App Store route. Verify your macOS version against the stated minimum before downloading, and decide early whether the App Store build or the annually refreshed non-App Store zip fits how you work.
Editorial conclusion
Adopt Pasteboard Viewer if you write Swift or Objective-C code that puts data on NSPasteboard or UIPasteboard and you need to see the exact type identifiers your code produces, including the legacy types the app hides. Skip it if you want clipboard history, cross-device sync or a non-programmer clipboard tool; the README states plainly that it is not a clipboard manager. Before installing, verify three things on your own machine: that your macOS version meets the stated minimum (macOS 26 for the current build, with older zips for macOS 15, 14, 13, 12, 11 and 10.15), whether you can use the App Store build or need the Dropbox non-App Store zip that receives updates roughly once a year, and how the app's hiding of obsolete types such as NSStringPboardType affects the debugging session you have in mind.
Community notes