How can I get bounty information from the API?

Question

I want to get information about all bounties that were active within last 3-4 days. This should include started, awarded and expired bounties. How do I do this?

Here are my thoughts.

• If a bounty is still active, the corresponding question will be included in /questions/featured endpoint response. Then from the bounty_user, bounty_amount and bounty_closes_date fields of answer type I can figure who, when and how much offered as a bounty.
• If a bounty has been awarded, the corresponding answer and question will have last_activity_date updated. Therefore, I can look through all recently active answers in the /answers endpoint.
  • bounty_user, bounty_amount will tell me who and how much is offered
  • by inspecting /users/{ids}/reputation-history for the bounty starter and answer owner, I can get timestamps for when bounty was started and ended.
• If a bounty has expired, I would still expect the corresponding question appear in recently updated questions. However, there wouldn't be any record of an expired bounty.
  • For expired bounties started by the question author, I might check /users/{ids}/reputation-history and see when and how much they allocated for this question.
  • For expired bounties started not by question author, I don't know what to do.

For example, this timeline shows that two bounties started, and both expired without a winner. The first bounty was started by the question author, the second bounty was started by a passer-by 1.5 years later. However, the API question timeline type does not include the "bounty_started" or "bounty_ended" event types, and indeed those are omitted from the API timeline response.

Answer 1

For expired bounties started not by question author, I don't know what to do.

You basically can't, or at least not without keeping track of formerly featured questions. This is caused by the fact that an expiring bounty and removing of the post notice does not update the questions last_activity_date. That makes searching for these questions impossible.

What you can do is:

• fetch all featured questions
• store their ids in a local datastore
• each hour¹ fetch all featured questions again
• compare new ids with stored ids, mark those that are no longer featured
• for each id that is no longer featured call Posts/{ids}/revisions
• filter the items on revision_type = 'vote_based'
• filter the items on comment starts-with '<b>Bounty Ended</b>'
• parse the comment to obtain the reason the Bounty was ended
• apply your other logic based on the reason.

Here is a code snippet that shows how you use the post/{ids}/revisions endpoint and handle its results.

const id = 4336045
const url = `https://api.stackexchange.com/2.3/posts/${id}/revisions?site=math&filter=!LIFDFz6ISS87ryfi9LAgrC`
fetch(url)
   .then( resp => resp.json())
   .then( data => data.items)
   .then( items => items.filter( i => i.revision_type === 'vote_based'))
   .then( items => items.filter( i => i.comment.indexOf('<b>Bounty Ended</b>') !== -1))
   .then( items => items[0])
   .then( item => { 
      const last = item.comment.indexOf('</b>')
      console.log(item.comment.substring(last+4))
    });

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^{1. I don't think it makes sense to run this more often. Removing expired notices/bounties is on a scheduled batch program on the SE end of things. Maybe if it gets confirmed it runs every 5 minutes you can pull more often.}