AI Engineering Interviews Now Focus on RAG Pitfalls, Evaluation and System Reliability

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As AI engineering roles grow more competitive, interviewers are shifting focus from tool familiarity to deeper judgment about what makes retrieval-augmented systems fail. Common problem areas include chunking strategy, hybrid search for exact matches, stale indexes, and confidently retrieving irrelevant content. A key differentiator between junior and senior candidates is the ability to diagnose whether failures stem from retrieval or generation, since each requires a different fix. Strong candidates also demonstrate structured evaluation practices — building fixed test sets from real failures and continuously feeding production errors back as regression cases. The ability to validate model outputs against a schema and maintain reliable evaluation pipelines is increasingly what separates those who have shipped production AI systems from those who have only prototyped them.

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RAG vs. Full-Context AI Reading: A Developer Tests Both on Real Documents

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AWS WAF Challenge used to block large-scale bot attacks at the network edge

A web security consultant was called in after a client's login page endured a week-long bot attack generating millions of requests from a vast number of IP addresses, making IP-based blocking ineffective. The attackers also rotated JA3 and JA4 fingerprints and industrialized token acquisition, partially bypassing an existing Cloudflare Turnstile integration by solving challenges in one country and replaying tokens from another. Because Turnstile validation occurred deep in the application stack, each rejected request still consumed CDN, load balancer, PHP, and database resources, driving up costs and degrading performance at scale. The consultant deployed AWS WAF's Challenge feature, which intercepts requests lacking a valid token at the network edge, before they reach any application infrastructure. This approach was applied across two attack scenarios — a legacy server-side HTML app and a modern single-page app calling a JSON API — using both integration modes offered by AWS WAF Challenge.

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ProgrammingDEV Community ·

Structured file design, not better prompts, fixes RAG hallucinations on legal dates

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One Unplugged Cable Took Down Whole-Home DNS, Exposing a Hidden Single Point of Failure

A home network in France appeared to lose internet access entirely after the owner accidentally unplugged the wrong cable, disconnecting not his NAS but his local DNS server. All devices — phones, laptops, and TV — showed no connectivity, yet the internet connection itself was fully functional throughout. Layered network testing quickly revealed that the router and raw IP access worked fine, but name resolution had completely failed. The outage stemmed from a self-hosted split-horizon DNS setup, where all internal subdomain resolution depended on a single machine with no reliable failover. Although a secondary DNS was configured, devices had not been set up to switch over quickly, illustrating that untested redundancy offers little real protection.

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