Claude Code adds GZIP request compression in v2.1.300

Claude Code v2.1.300, shipped October 14, 2026, now compresses large requests to api.anthropic.com with GZIP. A community report measured a 594,750-byte request body shrinking to 289,145 bytes, about 51% less. Brotli and Zstandard were rejected by the API in August tests.

• A 594,750-byte request body drops to 289,145 bytes with GZIP, about 51% less
• Compression applies even when telemetry is disabled
• Anthropic's API rejected Brotli, Zstandard and DEFLATE in August 2026 tests
• Compression can be disabled with CLAUDE_CODE_GZIP_REQUEST_BODIES=0