Anthropic OA Questions 2025: What Candidates Actually Saw
Last updated: June 2026
8+ Anthropic online assessment questions reported by candidates who took the OA in 2025. Sourced from 1Point3Acres, LeetCode, Blind, Glassdoor, and Reddit. Data grows as new reports are added.
Anthropic OA Format in 2025
Anthropic uses CodeSignal for its online assessment. Candidates report a multi-level problem structure where each level unlocks on completion of the prior one. The most frequently cited problem type is a Memory Database design challenge requiring layered implementation of get, set, and delete operations with TTL and snapshot support. The assessment tests both coding speed and API-design judgment under time pressure.
Anthropic OA Topic Patterns
Reported topics skew heavily toward data structure design (hash maps, queues, stacks), string parsing, and multi-step implementation problems. Pure algorithmic puzzles (tree traversal, dynamic programming) appear less often than design-style problems that test clean code organization.
Real Anthropic OA Questions from 2025
Anthropic Online Test Interview Experience for SDE Position
This post was last edited by Jing666 on 2025-10-3 15:25. Looks like I failed. Coding: Q4, interview question: distributed worker find mode, but I didn't have time to write the follow-up find median, o
Anthropic SDE Online Test Experience and C++ Interview Language Query
This post was last edited by Anonymous on 2025-10-05 18:44. The questions are below. Has anyone had an interview using C++? The HR called and told me I had to choose a language beforehand. I'm more fa
Cloud Storage System (Online Assessment)
Problem Summary Your goal is to build a simple, in-memory cloud storage system. This system will store files and their details, such as name and size. **Important:** This system runs entirely in me
Employee Management System (Online Assessment)
Problem Summary You need to build a simple system to manage employees. This challenge has **4 parts**. Each part gets a little harder than the last: 1. **Part 1**: Add new employees and track when
In-memory Database (Online Assessment)
Problem Overview You need to build a simple in-memory database. This challenge has **4 levels**. You must solve the current level to unlock the next one. 1. **Level 1**: Basic tools to add, update,
Task Management System (Online Assessment)
Task Management System (Interview Problem) ## Problem Summary You need to build a task management system. There are **4 levels**. Each level gets harder and adds new features: 1. **Level 1**: Build
Banking System (Online Assessment)
System Overview You need to build a bank system that runs in the computer's memory. There are **4 levels** to this problem. You must finish one level to move to the next. 1. **Level 1:** create acco
Recipe Manager (Online Assessment)
Problem Summary You need to build a recipe management system that runs in memory. The problem has **4 levels**. Each level adds new features to the previous one: 1. **Level 1**: Basic actions (Crea
Topic Breakdown (2025 OA)
Topics reported by candidates who took the Anthropic OA in 2025:
Difficulty Breakdown (2025 OA)
6
easy
1
hard
Difficulty labels are reported by candidates or inferred from LeetCode ratings.
How to Prepare for the Anthropic OA
Anthropic OA prep should focus on multi-level implementation problems rather than pure algorithm drilling. Practice building small in-memory systems (caches, queues, event logs) under timed conditions. CodeSignal uses a proprietary score that penalizes test failures and time taken, so test coverage and edge case handling are as important as speed. Review string manipulation and hash map patterns thoroughly. Candidates who have taken the Anthropic OA consistently recommend practicing on CodeSignal's General Coding Framework before the actual assessment.
The Anthropic OA is a timed, auto-graded coding test. Preparation is different from interview prep: you need to optimize for both correctness and speed, since partial credit requires passing test cases, not just showing reasoning.
- The assessment runs on CodeSignal, with a 90 to 120 minutes window. Familiarize yourself with the platform's editor and I/O format before test day.
- Practice timed sessions. Set a timer for 35 to 45 minutes per problem and simulate the real constraint.
- Topic emphasis: see the Topic Patterns section above for Anthropic-specific prep signals.
- Read the problem constraints carefully before writing code. The constraints often reveal the expected time complexity and algorithm type.
- Use the LeakCode database to review Anthropic OA questions from actual candidates. Pattern recognition across multiple sightings is a stronger prep signal than any single mock problem.
- If the OA includes a work simulation section, practice under realistic conditions. This section tests judgment and values alignment, not coding ability.
FAQ
What does the Anthropic OA look like in 2025?
Anthropic uses CodeSignal for its online assessment. Candidates report a multi-level problem structure where each level unlocks on completion of the prior one. The most frequently cited problem type is a Memory Database design challenge requiring layered implementation of get, set, and delete operations with TTL and snapshot support. The assessment tests both coding speed and API-design judgment under time pressure.
How long is the Anthropic OA?
The Anthropic OA runs 90 to 120 minutes on CodeSignal. Exact timing for your role may vary. Check your invitation email for the specific window allocated.
What platform does Anthropic use for the OA?
Anthropic uses CodeSignal for its online assessment. The platform supports multiple languages including Python, Java, C++, and JavaScript. Your invitation email will include the access link and any platform-specific instructions.
Are these real Anthropic OA questions?
Yes. All questions in the LeakCode database come from candidate reports on 1Point3Acres, Blind, Glassdoor, Reddit, and LeetCode. They are not AI-generated. Each question links to its source where available.
Other Anthropic OA Years
Related: Anthropic OA Hub · Anthropic All Questions · All OA Questions · Data Sources