How to open a code or text file online
Three steps, a few seconds, no software.
Open your .PROTO file
Drop it on the box, choose it from your device, or paste the text straight in.
View it instantly
Your .PROTO file opens neatly formatted with line numbers.
Search, copy or download
Search the text, jump to any line, then copy what you need or download a clean copy.
What is a .PROTO file?
Plain text that programs, servers and people write every day.
A .proto file is a plain-text schema for Protocol Buffers (protobuf), Google's data serialization system. Open it in any text editor or VS Code with the vscode-proto3 extension. To use it, compile it with protoc, the Protocol Buffer Compiler, which generates source code for your target language.
Programs that open .PROTO files
| Full name | Protocol Buffers Definition File |
|---|---|
| Developer | |
| First released | 2008 (open-sourced; internally at Google since ~2001) |
| Category | Text & Code |
| MIME type | text/plain |
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Frequently asked questions
Is my .PROTO file uploaded anywhere?
No. The file is read and highlighted for you.
Why do some characters look wrong (é, ł)?
That usually means the file was saved in one encoding and opened in another. We detect UTF-8, UTF-16 and the Windows-1250/1252 code pages automatically and show which one was used.
Can it handle huge log files?
Yes, up to 50 MB. Only the lines on screen are drawn, so scrolling stays smooth. Syntax colours are switched off for files over 1.5 MB to keep things fast.
How do the log level filters work?
We find levels like ERROR, WARN, INFO and DEBUG on each line. Lines without a level, such as stack traces, stay with the entry above them, so filtering to errors keeps the full trace.
Can I edit the file?
This is a viewer. To change code, download it or copy it into your editor. Converting encodings and line endings is planned.
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