Note

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Sqinn is an alternative to the SQLite C API. Sqinn reads requests from stdin, forwards the request to SQLite, and writes a response to stdout. It is used in programming environments that do not allow calling C API functions.

The SQLite database library is written in C and provides an API for using it in C/C++. There are many language bindings. If you cannot or do not want to use one of the available language bindings, and your programming language allows the creation of subprocesses (fork/exec), an option might be to communicate with SQLite over stdin/stdout, using Sqinn.

Sqinn provides functions to execute SQL statements and query database rows.

All function calls and the binary protocol used for sending request and receiving responses is described in rfc.txt.

For the Go (Golang) language binding, see https://github.com/cvilsmeier/sqinn-go, for benchmarks, see https://github.com/cvilsmeier/sqinn-go-bench.

Compiling

See the included build.sh and build.bat script for compiling Sqinn. I have tested it on the following platforms:

• Debian Linux 12 amd64 (gcc)
• Windows 10 amd64, using MSVC Build Tools (cl.exe)
• Macos 13 amd64 (clang)

The releases page contains a tar file with pre-built binaries for linux-amd64, windows-amd64, macos-amd64 and macos-arm64, see https://github.com/cvilsmeier/sqinn/releases.

If you want to compile Sqinn, have gcc/cl.exe/clang installed and follow the steps:

git clone https://github.com/cvilsmeier/sqinn
cd sqinn
chmod a+x script/*.sh
script/build.sh

The build script creates a bin subdirectory that the build results go into. Test it with:

bin/sqinn test

See also https://github.com/cvilsmeier/sqinn/actions for build actions for Linux, Windows and MacOS.

Command line usage

There isn't really one. Sqinn is not used by humans, it's used by other programs. That said:

$ sqinn
sqinn v2.0.0 - SQLite over stdin/stdout.

Usage:
    sqinn <command> [options...]

The commands are:

    run               Read requests from stdin and write responses to stdout.
    test              Execute selftest and exit.
    version           Print version and exit.
    sqlite            Print SQLite library version and exit.
    help              Print help page and exit.

The options are:

    -db <dbname>      Database name. Default is ":memory:"
    -loglevel <level> Log level: 0=off, 1=info, 2=debug. Default is 0 (off).
    -logfile <file>   Log to a file. Default is empty (no file logging).
                      Note: Logfile is appended and will grow unlimited.
    -logstderr        Log to stderr. Default is off (no stderr logging).

Limitations

Single threaded

Sqinn is single threaded. It serves requests one after another.

API subset

Sqinn supports only a subset of the many functions that the SQLite C/C++ API provides. Interruption of SQL operations, incremental blob i/o, vfs and extension functions are not supported, among others.

Contributing

I have to reject most PRs and feature requests. Why? Because I use sqinn for my own projects, and I need it to be fast, secure, reliable and easy to maintain. I cannot include every feature under the sun. I give it away for free, so everybody can adjust it to his or her own needs.

Changelog

v2.0.0

• New I/O protocol
• SQLite Version 3.50.4 (2025-07-30)