一个附加的HTTP状态代码的（ RFC6585 ）是
- 429个请求过多
我在哪里可以找到与此HTTP响应状态有用的HTTP / REST API速率限制HTTP响应头的例子吗？
Answer 1:
以下是限制HTTP响应头HTTP API率的一些例子。 Github上，Vimeo的，Twitter和Imgur：从四种常见的REST API措施：
Github的速率限制http://developer.github.com/v3/#rate-limiting
#=============================#=============================================#
# HTTP Header # Description #
#=============================#=============================================#
| X-RateLimit-Limit | Request limit per hour |
+-----------------------------+---------------------------------------------+
| X-RateLimit-Remaining | The number of requests left for the time |
| | window |
+-----------------------------+---------------------------------------------+
Vimeo的速率限制http://developer.vimeo.com/guidelines/rate-limiting
#=============================#=============================================#
# HTTP Header # Description #
#=============================#=============================================#
| X-RateLimit-Limit | Request limit per day / per 5 minutes |
+-----------------------------+---------------------------------------------+
| X-RateLimit-Remaining | The number of requests left for the time |
| | window |
+-----------------------------+---------------------------------------------+
| X-RateLimit-Reset | The remaining window before the rate limit |
| | resets in UTC epoch seconds |
+-----------------------------+---------------------------------------------+
Twitter的REST API速率限制https://dev.twitter.com/docs/rate-limiting/1.1
注：Twitter使用头与像Vimeo的相似的名字，但在每个名字另一个冲刺。
#=============================#=============================================#
# HTTP Header # Description #
#=============================#=============================================#
| X-Rate-Limit-Limit | The rate limit ceiling for that given |
| | request |
+-----------------------------+---------------------------------------------+
| X-Rate-Limit-Remaining | The number of requests left for the |
| | 15 minute window |
+-----------------------------+---------------------------------------------+
| X-Rate-Limit-Reset | The remaining window before the rate limit |
| | resets in UTC epoch seconds |
+-----------------------------+---------------------------------------------+
Imgur API速率限制http://api.imgur.com/
#=============================#=============================================#
# HTTP Header # Description #
#=============================#=============================================#
| X-RateLimit-UserLimit | Total credits that can be allocated |
+-----------------------------+---------------------------------------------+
| X-RateLimit-UserRemaining | Total credits available |
+-----------------------------+---------------------------------------------+
| X-RateLimit-UserReset | Timestamp (unix epoch) for when the credits |
| | will be reset |
+-----------------------------+---------------------------------------------+
| X-RateLimit-ClientLimit | Total credits that can be allocated for the |
| | application in a day |
+-----------------------------+---------------------------------------------+
| X-RateLimit-ClientRemaining | Total credits remaining for the application |
| | in a day |
+-----------------------------+---------------------------------------------+
Answer 2:
除了API特定的头文件，不要忘了谦虚，标准Retry-After头。
文章来源: Examples of HTTP API Rate Limiting HTTP Response headers [closed]
