Intel HEX Viewer Online
Open an Intel HEX or Motorola S-record firmware image to see what it puts where in memory: the segments, gaps and overlaps, a hex view by address and a data inspector. Every record is checked, and bad lines are listed. No account and no upload.
Intel HEX Viewer & S-Record Viewer for VS Code and Cursor, free
- Opens .hex, .ihex, .ihx, .srec, .s19, .s28, .s37 and .mot files with a click, read-only and with no network.
- Memory map of segments, gaps and overlaps, every record checked, and the bad lines listed.
- Hex view by address, a data inspector, and the raw text with filter and copy.
Optional Zovo Pro, USD 19 once: convert to HEX, S19 or binary, compare two images, and checksum or CRC over a range. 3 free tries for each.
Drop a .hex or .s19 file here
or
Intel HEX (.hex, .ihex, .ihx) and Motorola S-record (.srec, .s19, .s28, .s37, .mot), up to 200 MB. The format is found from the first line.
Open this in VS Code or Cursor
The free Intel HEX Viewer & S-Record Viewer extension opens .hex, .ihex, .ihx, .srec, .s19, .s28, .s37 and .mot files in VS Code and Cursor with the same memory map, problems, hex view by address and data inspector, plus the raw text with filter and copy.
Free, MIT license. About Intel HEX Viewer & S-Record Viewer for VS Code.
Zovo Pro
Convert to HEX, S19 or binary, compare two images and compute a CRC. Zovo Pro, USD 19 once.
In the Intel HEX Viewer & S-Record Viewer extension, Zovo Pro saves an image as Intel HEX, S19, S28 or S37 or as a flat binary with the gaps filled, compares two images by address with a Markdown report, and computes a checksum or CRC over an address range (CRC-32, CRC-16/CCITT-FALSE, MODBUS, MD5, SHA-256 and more) and can write it into a copy of the file. Each Pro tool works 3 times for free. One payment covers the Pro tools in 22 Zovo extensions. Everything that is free stays free.
After a card payment you get a key on the page. With GitHub Sponsors you sign in from the extension. Details on the Zovo Pro page.
Related tools
- Hex Viewer & Binary Viewer. Opens any file as hex in VS Code, with a data inspector.
- ELF Viewer & PE Viewer. Shows the headers, sections and symbols of ELF, PE and Mach-O files.
- Linker Map Viewer & Map File Analyzer. Shows memory use from GNU ld map files in VS Code.
- Hex Viewer Online, free in your browser.
- DBC Viewer Online, free in your browser.
- EDI Viewer Online, free in your browser.
Questions
Is my firmware uploaded anywhere?
No. The page reads the file inside this tab with JavaScript. Its Content Security Policy sets connect-src to none, so the page cannot send your image anywhere. Open the Network tab of your browser tools and you will see no request when a file opens.
Which records does it read?
Intel HEX types 00 (data), 01 (end of file), 02 and 04 (segment and linear address), 03 and 05 (start address). S-records S0 (header text), S1, S2 and S3 (data with 16, 24 and 32-bit addresses), S5 and S6 (record count), and S7, S8 and S9 (start address). Lowercase hex digits and Windows or Unix line ends both work.
What does it check?
The checksum of every record, that the byte count matches the length, the start code and hex digits, known record types, the end record, the S5 or S6 count against the data records, text after the end record, and bytes written twice, with a note on whether the values differ. Each problem has its line number.
How do I read the memory map?
Records that touch are joined into segments. The bar shows the data in blue and the gaps blank, with long gaps drawn shorter so small blocks stay visible. The table lists the start, end and size of each segment and the gap before it. Click a segment to see its bytes.
What does the data inspector show?
Click a byte in the hex view to read it, and the bytes after it, as unsigned and signed 8, 16, 32 and 64-bit numbers in little and big endian, as a 32-bit float and as ASCII. Gaps show as two dashes in the hex view, and Go to address takes hex like 0x08000000.
Can it convert or compare images?
Not this page. Converting to Intel HEX, S19 or a flat binary, comparing two images and a CRC over a range are Zovo Pro tools in the free Intel HEX Viewer & S-Record Viewer extension for VS Code, with 3 free tries each.
Does it work offline?
Yes. After the first visit the page keeps a copy of its own files, so it opens firmware files with no connection.
What is free and what is Zovo Pro?
Everything on this page is free. In the VS Code extension, the memory map, problems, hex view, data inspector and raw text are free too. Convert, compare and checksum or CRC are Zovo Pro, with 3 free tries each. One USD 19 payment covers the Pro tools in every Zovo extension.