What is the problem?
给中文新手的环境变量 missing 排查流程：先确认缺哪个变量、在哪个环境缺、本地和部署平台是否一致，再处理公开变量、敏感密钥和客户授权边界。
Quick solution
Treat this as a Vercel tutorial issue. First confirm the environment, inputs, permissions, logs, and delivery boundary. Then use the linked deep guide for the full checklist before changing production code or promising a result.
Read the deep guideDetailed steps
- 保存原始报错。记录命令、页面、接口、部署平台日志和报错变量名。
- 只记录变量名，不记录真实值。比如写 `DATABASE_URL` 缺失，不写具体连接串。
- 判断发生环境。本地 dev、本地 build、预览部署、生产部署、服务端请求、客户端页面要分开。
- 看项目说明。检查 README、`.env.example`、配置文件、校验脚本和部署说明。
- 判断变量类型。公开变量、服务端密钥、数据库连接、第三方 API key、功能开关要区别处理。
- 找配置位置。本地放本地 env 文件；部署平台放对应环境的变量配置；客户密钥由客户自己配置。
Commands or code
The source article does not include a copyable command block. Do not invent commands here; follow the diagnostic steps in the deep guide and validate changes in the real project environment.
Risk notes
Confirm the real project environment, account permissions, platform rules, and output quality before delivery. Do not ship AI-generated changes without human review, and do not claim indexing, income, deployment success, or ranking improvements without measured evidence.