Decagon

A recruiter call and a practical coding screen, then an onsite of pair coding, agent-system design, a project deep dive and a values round; three to four weeks overall.

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  Send requests in batches of five and retry failures after a delayCodingDeliver a list of requests to an API that accepts at most five requests per call. Some requests in a call can fail; a failed request may be retried only after its own delay has…

  Last asked Sep 2026Were you asked this too?
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  Project deep dive: present a project you ledBehavioralPresent a project you led in about 20 minutes: context, your role, the architecture, three hard trade-offs, metrics, cost and return, and what you would change. Then take 25…

  Last asked Sep 2026Were you asked this too?
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  Design the security architecture for an LLM chatbotAI systemA company runs a customer-facing chatbot built on a language model. Design its security: protecting the bot from abuse and prompt injection, limiting the data it can see and the…

  Last asked Sep 2026Were you asked this too?
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  Shopping cart with discounts, undo and redoCodingBuild a shopping cart with item discounts where every mutation supports undo and redo. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Sep 2026Were you asked this too?
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  Design a distributed job schedulerSystem designDesign a service that runs millions of scheduled and on-demand jobs (cron-like and one-off) reliably across a fleet of workers.

  Last asked Aug 2026Were you asked this too?
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  Count legal tic-tac-toe game sequencesCodingCount the legal game sequences on tic-tac-toe boards, including a 4x4 three-in-a-row variant, enumerating valid play orders with backtracking. Reported on 1point3acres' Decagon…

  Last asked Jul 2026Were you asked this too?
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  Recipe shopping cart with bulk discountsCodingModel a recipe shopping cart that prices ingredients with bulk discounts per ingredient. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Jul 2026Were you asked this too?
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  Cart with nested transactionsCodingImplement a cart whose updates run inside nestable transactions that commit or roll back as a unit. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Jul 2026Were you asked this too?
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  Sliding window conversation scores with percentilesCodingTrack conversation quality scores in a sliding window and answer percentile queries over the current window. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Apr 2026Were you asked this too?
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  Design a customer-service AI agent with tools and guardrailsAI systemYou built a small conversational agent with two tools for the take-home. Now design the real thing: a platform that runs AI agents for many consumer brands, over chat and voice…

  Last asked Mar 2026Were you asked this too?
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  Exclusive time of functionsCodingFrom function start and end logs, compute each function's exclusive execution time excluding nested calls. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Mar 2026Were you asked this too?
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  Design an AI gatewayAI systemDesign a gateway that sits between a company's services and the language-model providers they call. Cover routing requests across providers and models, failover, rate limits and…

  Last asked Feb 2026Were you asked this too?
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  Design a real-time AI voice agentAI systemDesign a system in which callers talk to an AI agent over the phone or in an app in real time: speech recognition, the language model, speech synthesis, keeping the response delay…

  Last asked Feb 2026Were you asked this too?
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  Sliding window average with updatesCodingMaintain a sliding window average over a stream with insert, average query and value updates, all efficient. Reported on 1point3acres' Decagon bank; reconstructed in our own words.

  Last asked Jan 2026Were you asked this too?
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  Design an evaluation harness for a customer-support AI agentAI systemA company's AI agent answers its customers over chat and takes actions through tools (refunds, plan changes, escalations). Every prompt, model, tool or policy change can break it…

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