What Is an OA (Online Assessment)?

Full Definition

OAs (Online Assessments) became standard at large tech companies in the mid-2010s as a way to handle high applicant volume without burning recruiter or engineer time on phone screens. The candidate receives a link (usually HackerRank, Codility, or a custom platform), has a fixed window to complete it (often 60-120 minutes), and submits code that is automatically graded against test cases. The OA is usually the first technical filter after resume review. Pass rates vary by company but are typically 30-50% — companies tune the bar based on hiring volume. Amazon's OA is one of the most distinctive: two coding problems plus a 'work simulation' (behavioral multiple-choice scenarios mapped to Leadership Principles) plus a 'work styles' assessment. Google's OA is shorter (2 problems, 60-90 min) and used mostly for new-grad and intern roles. Meta typically skips OAs for experienced hires and goes straight to phone screens. The OA stage is where the highest absolute volume of candidates is filtered, so it's worth disproportionate prep time despite being conceptually simpler than later rounds. Common pitfalls: running out of time on the second problem, failing edge cases on large inputs (an O(n^2) solution times out where O(n log n) would pass), and not testing locally before submitting.