Hi,
I am assuming you are not talking about native crashes as in Sentry + custom native client + stack traces, but rather that you’re already sending a JSON payload to Sentry.
The source code is sent as part of the event! The relevant keys in the frame are pre_context (lines before the crashing line), post_context (lines after the crashing line) and context_line (the line where it crashed). See https://docs.sentry.io/clientdev/interfaces/stacktrace/ for an example.