Arista Networks's Interview Process (2026)

Blog / Arista Networks's Interview Process (2026)

The Arista Networks software engineer interview process typically runs 3 to 5 rounds and places a heavy emphasis on low-level systems knowledge, C/C++ proficiency, and networking fundamentals, setting it apart from the standard big-tech hiring pipeline most candidates are used to.

Recruiter Screen: A short call, usually around 20 minutes, to cover your background, interest in Arista, and logistics like location and visa status.
Online Assessment / Initial Technical Screen: A coding session typically conducted on CoderPad, usually lasting 60 to 90 minutes, with 2 to 3 questions. Many teams require solutions in C or C++.
Technical Phone Screen: One or two 60-minute sessions focusing on data structures and algorithms with a systems twist, including topics like memory management and pointer manipulation.
Onsite / Final Loop: Usually 3 to 4 virtual rounds covering advanced coding and concurrency, networking and OS fundamentals, low-level system design, and a hiring manager conversation about your past work and team fit.

To prepare effectively, focus your study plan across these core technical areas that Arista consistently tests:

Data Structures & Algorithms (DSA): Coding questions with a systems and implementation focus, often requiring C or C++.
Low-Level Design: Designing thread-safe data structures and memory-efficient systems at the code level.
System Design: Low-level system architecture questions rather than high-level distributed systems.
CS Fundamentals: Operating systems, networking protocols, and how code interacts with hardware.
Behavioral: A hiring manager round focused on past projects, technical decision-making, and team fit.

1. Data Structures & Algorithms (DSA)Arista's coding questions lean toward Medium difficulty, but the bar is in the implementation quality. They want production-ready code with correct edge case handling, not just a working outline. One 2026 candidate reported being screened out specifically for C++ syntax fluency, so comfort in the language matters as much as the algorithm itself.Linked lists come up frequently, covering reversal, cycle detection, and node deletion. Problems like Merge Two Sorted Lists and Remove Linked List Elements (Odd Values Only) are representative of what gets asked.Bit manipulation and string parsing also appear regularly, often with a networking flavor. Expect questions like IP address validation, similar to Restore IP Addresses, or checking for duplicates using bit arrays. Start your prep with our top 100 DSA questions and make sure to cover linked lists, bit manipulation, and trees.

2. Low-Level DesignArista frequently asks candidates to implement thread-safe data structures from scratch during live sessions. A classic example is the Design LRU Cache, which they expect with O(1) get and put operations and thread safety considered.You may also be asked to design a bounded queue with proper locking, or walk through the memory layout of a structure. Practice our Low-Level Design examples, with an emphasis on manual memory management, since relying on garbage-collected languages or standard library wrappers without understanding what's underneath is a common stumbling block.

3. System DesignArista's system design questions focus on low-level architecture rather than the classic 'design Twitter' style problems. You are more likely to be asked to design a packet buffer, a thread-safe queue, or a custom memory allocator than to whiteboard a distributed caching layer.That said, understanding foundational design concepts still helps. Review system design core concepts and use our System Design practice tool to get comfortable thinking through architecture at a whiteboard level before drilling into the lower-level specifics Arista cares about.

4. CS FundamentalsArista has a dedicated round for networking and OS fundamentals, even for general software engineering roles. You should be comfortable explaining the lifecycle of a packet, how ARP and DHCP work, and the difference between L2 and L3 switching. Brush up on networking and caching fundamentals, and get solid on OSI model layers, BGP neighbor states, and how a switch differs from a router.On the OS side, expect questions about stack vs. heap allocation, memory alignment, and how atomic variables or mutex locks are implemented at the CPU level. Review operating systems concepts to cover process scheduling, virtual memory, and system calls. Interviewers want to know what happens at the hardware level when a specific line of code runs, not just what the code does.

5. BehavioralThe behavioral portion at Arista is typically a hiring manager or director round that combines culture fit questions with a technical discussion of your past projects. Expect to talk through specific engineering decisions you made, including trade-offs around performance or correctness.Prepare a few stories about systems-level work you have done and be ready to go deep on the technical details.Use our Behavioral Interview Course to structure your answers clearly, and review the Behavioral Playbook for guidance on framing trade-off decisions in a way that resonates with engineering-focused interviewers.

ConclusionArista rewards candidates who think precisely, write clean C/C++, and can connect code behavior to what happens at the OS or hardware level. Start by getting comfortable with manual memory management and Medium-level DSA, then layer in networking and OS fundamentals. Follow the Arista Networks Interview Roadmap for a structured, step-by-step path to working through every stage of the process.

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