Hexter vs. Hex Fiend: Which Mac Hex Editor Should You Use
If you searched for a hex editor on Mac, you almost certainly ran into Hex Fiend. It’s free, open source, and it’s the default recommendation on nearly every “best hex editor for Mac” list. It’s also genuinely good software. This isn’t a “why our app is better” post. It’s an honest look at where Hex Fiend is still the right call, and where Hexter does things differently enough to matter.
The short version
Hex Fiend is a mature, free, open-source tool built primarily around raw editing power at massive scale. Hexter is a newer app built around a different priority: making it hard to accidentally damage a file you’re just trying to look at. If you already know exactly what you’re doing and you need to comfortably diff or edit files in the tens of gigabytes, Hex Fiend is the more capable tool for that today. If you want a hex editor that’s cautious by default and understands common file structures out of the box, that’s what Hexter is built for.
Feature by feature
| Hex Fiend | Hexter | |
|---|---|---|
| Price | Free, open source (BSD license) | Not yet launched on the Mac App Store |
| Large file handling | Handles files up to roughly 118 GB without loading them into memory | Reads bytes on demand via a chunked cache; not benchmarked yet at Hex Fiend’s scale |
| Editing safety | Has an explicit Read-Only Mode you can enable or set as default, but that’s not the out-of-the-box default itself | Opens every file read-only, always, with no preference to change that default; editing requires an explicit toggle, and edits sit in a reversible patch layer until you save |
| Overwrite protection | Standard save; no built-in backup step mentioned in its docs | Overwriting the original file requires confirmation and offers an automatic backup copy (a single .hexter-backup file that’s replaced on each subsequent save, not a timestamped history) |
| Binary diff | Insertion/deletion-aware diff; no size limit is documented anywhere in its docs or release notes | Real diff algorithm, but currently capped for very large comparisons, falling back to a coarser result above that size |
| Built-in structure parsing | Ships a genuinely large bundled template library (~17 categories), but you browse and apply a template manually | PNG, ZIP, Mach-O, WAV, and SQLite structure detected and parsed automatically on open, no template to pick |
| Hashing | Not a built-in feature | CRC32, Adler32, MD5, SHA-1, SHA-256, and SHA-512, computed over the file in the background |
| Strings, bookmarks, anomaly detection | Not built in | All built in: string extraction, named bookmarks with notes, and a scan for entropy spikes, suspicious byte runs, and format-signature mismatches |
| Interface | AppKit, functional, dates back over a decade | Native SwiftUI, dark mode, built for current macOS |
| Extensibility | Two-clause BSD license, embeddable as a framework in other apps | Not designed to be embedded; a standalone app |
| Custom binary templates | Supported via its template system for arbitrary formats | Not supported yet; the five built-in parsers cover common formats but there’s no user-defined template language |
Where Hex Fiend is still the better choice
If you regularly work with files in the tens of gigabytes, firmware dumps, disk images, large database exports, Hex Fiend’s memory model and its track record at that scale are hard to argue with. Its diff tool has no documented size limit, which matters if your job involves comparing large binaries. It’s also free, which is worth something on its own, and if you’re building a tool that needs to embed a hex editing component, its BSD license and framework design make that possible in a way a standalone app doesn’t.
Hex Fiend also already ships a substantial bundled template library, roughly 17 categories covering executables, archives, audio, and more, so it’s not starting from zero on structured formats either. If you need a custom template for something obscure or proprietary that isn’t already covered, Hex Fiend’s template system (and tools like 010 Editor or ImHex, which go further in this direction) will get you there. Hexter’s structure parsing works well for the five formats it knows, PNG, ZIP, Mach-O, WAV, SQLite, but it doesn’t let you define your own.
Where Hexter does something different
The core difference isn’t a feature, it’s a default. Hex Fiend does have a Read-Only Mode, but you have to know to turn it on (or set it as your default in preferences); out of the box, it opens a file in an editable mode. Hexter opens every file read-only, always, with no setting to change that. Editing is something you turn on deliberately, with changes held in a patch layer you can review and revert before anything touches the original file. If you spend more time looking at files than editing them, and most hex-editor sessions are actually inspection, not editing, that default matters more than it sounds like it should. It means opening an unfamiliar file, someone else’s config, a downloaded firmware image, a file you’re debugging, carries no risk by default, without you having to remember to flip a switch first.
The second difference is what happens automatically when you open a file Hexter recognizes. Instead of a flat wall of hex, you get the actual structure: PNG chunk boundaries with their type and CRC, a ZIP archive’s local file headers, a Mach-O binary’s load commands, a SQLite file’s header fields, parsed and laid out next to the raw bytes, with zero setup. Hex Fiend’s bundled templates can get you similar detail, but you’re browsing a template list and applying one yourself first.
Beyond that, hashing, string extraction, and anomaly detection (entropy spikes, signature mismatches, suspicious byte runs) are built into Hexter directly, where in Hex Fiend’s world those are usually a separate tool.
The honest recommendation
Use Hex Fiend if you’re already comfortable with hex editors, you need to handle very large files, or you want a free tool with a long track record and an active community. Use Hexter if you want a hex editor that assumes you might be looking at a file you don’t fully trust yet, defaults to not touching it, and tells you more about common formats without any setup. Neither is wrong. They’re built around different assumptions about who’s using them and why.
Hexter is in active development. If read-only-by-default, built-in structure parsing, and a modern native interface sound like what you want out of a hex editor, that’s the app to keep an eye on.