How to reduce LLM costs by 70 times: experience migrating from Claude Sonnet to Qwen 3.5 Flash
JobPath migrated from expensive Claude Sonnet to cheap Qwen 3.5 Flash for job card generation, cutting monthly costs from ~$2000 to ~$30 while quality dropped slightly from 4.48 to 4.06 on a 1-5 scale. The article details selection via evaluation with a blind judge, issues with cheap models (empty responses, type mismatches, field typos), and error-handling lessons including a billing mistake that wasted 16,000 calls in one night.
Anthropic
Alibaba/Qwen
DeepSeek



