Edit Intel HEX Files
In Your Browser
Stop hand-fixing Intel HEX checksums. Edit EPROM firmware files in your browser - automatic checksum recalculation, TXT ↔ HEX conversion, works completely offline.
Or download a sample .hex and drag it into the editor to try instantly.
Open Any .hex File
Drag & drop or browse. Parses Intel HEX records (data, EOF, extended linear address). Validates checksums on load.
Edit with Live Checksums
Click any byte, type hex. Per-row Intel HEX record checksum updates instantly. Overall 8/16-bit sum, XOR, CRC-16 shown live.
TXT ↔ HEX Conversion
Import binary-pattern .txt (one byte per line, e.g. 00111000) → valid .hex. Export current bytes back to .txt with 0xFF fill for gaps.
Save In Place
File System Access API overwrites original file with recalculated checksums. Falls back to download. Preserves original record structure.
Zero Install, Works Offline
Single HTML file. No server, no build, no dependencies. Save it, run it anywhere — air-gapped labs, CI pipelines, field devices.
Handles 1 MB+ Dumps
Virtualized rendering — only visible rows in DOM. Fixed-layout tables keep headers aligned. Responsive at any size.
Editor Preview
Want Team Features?
We're building the workflow tools firmware teams actually need: side-by-side diff (two .hex files, per-record highlighting), shared annotated sessions (bookmark + comment across a team), firmware version compare, and a CI/CD API for automated checksum verification in pipelines. The free offline editor stays free forever — join the waitlist to get early access and influence the roadmap.
No spam. Unsubscribe anytime. We'll only email when team features land or for major updates.