Describe a challenging bug you fixed in a previous project. What was your debugging process, and how did you eventually resolve it?

LeetCode #139 - Word Break:\nGiven a string s and a dictionary of strings wordDict, return true if s can be segmented into a space-separated sequence of one or more dictionary words. You may assume the dictionary does not contain duplicate words.\n## Example:\n**Input:** s = 'leetcode', wordDict = ['leet', 'code']\n**Output:** true\n\n**Input:** s = 'applepenapple', wordDict = ['apple', 'pen']\n**Output:** true\n\n**Input:** s = 'catsandog', wordDict = ['cats', 'dog', 'sand', 'and', 'cat']\n**Output:** false\n\n## Constraints:\n- 1 <= s.length <= 300\n- 1 <= wordDict.length <= 1000\n- 1 <= wordDict[i].length <= 20\n- s and wordDict[i] consist of only lowercase English letters.

Can you explain how you would design a URL shortening service like Bitly? What considerations would you take into account for scalability, performance, and data integrity?