jake kara, software engineer ‣ API keychain to bypass rate limits ░

API keychain to bypass rate limits

I wrote an API keychain to use multiple keys on the same API, getting around daily max-call rate limits.

Here’s the repo

I called it API hammer. It’s a proof-of-concept keychain module for handling multiple keys on the same API, potentially bypassing rate limits. Keeps track of requests per day, and when the limit is exhausted, uses another api key.


# import the module
import apihammer

# create a 'connection'
# service corresponds to keys.json file "service" field
conn = apihammer.connection(service="noaa")

# get a valid api key (non-exhausted)
k = conn.api_key()

# make your API call...


By default, apihammer uses a file called keys.json for an api keychain file. Each time you call the api_key() method, apihammer updates the keychain file. When the calls_per_day is reached for an api key, it is now considered exhausted for that day.

You will want to copy keys.json.example to keys.json like so:

$ cp keys.json.example keys.json

and modify the settings appropriately.

The structure of keys.json is an array of objects. You must specify a “service” property, a “key” (the api key itself) property. uname is not yet used, but it is intendend to help you keep track of which email address your key is associated with. “calls_per_day” must be set to the max calls the API allows per day.

apihammer will add fields “calls” and “last_call” for its bookkeeping purposes.

calls per second

apihammer can throttle the api_key() function if one calls:


All this will do is force the api_key() method to sleep for 1/5 of a second before returning. Since your API request method should be dependent upon the return value of api_key(), this will cause your code to obey the API’s calls-per-second rate limiting.

Refactor remnants, proof of concept code

There is some left-over code in apihammer from when I initially thought I might also use the module to make the api calls, but I realized that’s not the best design. There are some methods that aren’t used. I wanted to get the code out fast. Along those lines, I haven’t exhaustively tested this.

Since this code hasn’t been tested much, please consider it a proof of concept.

Be nice

If some data provider is good enough to provide an API you should generally respect the nature of their rate limiting and not try to get around it. But sometimes you have to be a jerk.