Why nginx doesn’t handle chunked encoding responses from my backend properly?

Q: My backend server appears to send HTTP/1.0 responses using chunked encoding but nginx doesn’t handle it correctly. For instance, I’m using nginx as a frontend to my node.js application and instead of pure JSON from backend, nginx returns something framed in decimal numbers like

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{"error":"query error","message":"Parameter(s) missing: user,password"}
0

A: Your backend violates HTTP specification (see RFC 2616, "3.6 Transfer Codings"). The "chunked" transfer-codings must not be used with HTTP/1.0. You’d need to either fix your backend application or upgrade to nginx version 1.1.4 and newer, where an additional code was introduced to handle such erratic backend behavior.