Submission: Edu-Insight Assistant What I build I built the Edu-Insight Assistant, a tool designed for educators to bridge the gap between complex school management data and actionable insights. It allows teachers to query students performance data using natural language, turning educational evaluation into a conversation rather than a manual data-processing task. Demo 🔗 Link: Passion-challenge How I Built It I utilized Next.js for a responsive, performant frontend and hooked it up to Google Gemini 3.5 API. The core logic involves a server-side API route that takes a teacher's natural language questions, prompt Gemini to generate the necessary SQL, and execute that query against a database. This architecture makes data exploration accessible to non-technical educators. Prize Categories: - Best Use of Google AI : Leveraged Gemini 3.5 Flash for natural language-to-SQL translation and result interpretation. - Best Use of Snowflake: Designed with an extensible data layer ready for production-scale analytical workloads in Snowflake.

I built a small index basket app on Robinhood Chain because I wanted to understand the developer path from the first contract deploy all the way to a working frontend. The app is intentionally plain: a user deposits Stock Tokens, which are blockchain tokens that represent real equity exposure, and receives an ERC-20 basket share. ERC-20 is Ethereum's standard token interface, so a compatible token exposes familiar methods like balanceOf , transfer , and approve . The basket share is priced from live price feeds, and the user can redeem it back into the underlying Stock Tokens. That's the part that made this interesting to me. The chain is custom, but the app path is not. I still wrote Solidity, deployed with Foundry, read contract state with viem, and wrote transactions from React with wagmi. If you've built normal web apps, think of the chain's RPC endpoint as the API base URL. A wallet is login plus a signing key. A smart contract is backend code you deploy to the chain, except you should treat it like immutable infrastructure because you don't get to hot-patch it casually later. The demo and source are here: App: https://robinhood-chain-dapp.vercel.app/ Code: https://github.com/hummusonrails/robinhood-chain-dapp-example The custom chain still feels like the EVM Robinhood Chain is a custom Arbitrum Chain, which means it runs as a dedicated chain on the stack of Arbitrum, an Ethereum scaling system. It is also EVM-compatible. EVM means Ethereum Virtual Machine, the runtime that executes Solidity contracts, so the tooling surface looks like the Ethereum developer flow many tutorials already teach. An L2, or rollup, is a chain that executes transactions separately and then posts compressed proof or transaction data back to Ethereum. Robinhood Chain uses Ethereum blobs for data availability, which is a cheaper Ethereum data lane for rollups to publish the data needed to reconstruct chain state. Gas, the metered compute fee you pay to run transactions, is paid in ETH.

Hi everyone! this is my first post here on dev. About 4 days ago I realized I'm stuck as a mid-level backend engineer, and honestly, not even a good one. Some background: I have a CS degree and started working as a software engineer in 2022. I spent a year and a half at a financial company, then moved to one in the tourism industry, and now I work at a client-based company doing multiple projects. For a while I've felt like my growth here is blocked, so I started looking for another job. That search made me realize something uncomfortable: I've been relying on AI way too much. So now I'm trying to cut down on AI for my tasks, and I've decided to build a couple of projects that'll actually challenge me and help me learn. I've got two projects in mind: a stock exchange engine and a collaborative music production system. I'll share how it goes, including the parts I get wrong! (English isn't my first language, so I used AI to help polish the wording. The story and the projects are all mine.)

skip에서 partition overwrite로: business_date 재처리를 Iceberg로 다시 표현하기 이전 글에서는 같은 source_hash 가 다시 들어왔을 때 기존 successful run을 재사용하는 idempotency를 다뤘다. 하지만 재처리에는 두 종류가 있다. 1. 같은 입력이 다시 들어온 경우 -> skip이 맞다. 2. 같은 business_date의 정정 입력이 들어온 경우 -> skip하면 안 된다. -> 같은 날짜의 gold 결과를 중복 없이 교체해야 한다. manufacturing-data-platform-mini 의 B5 slice는 두 번째 문제를 아주 작게 다룬다. 전체 Spark pipeline을 만든 것이 아니다. gold_daily_metrics Iceberg table 하나를 local Spark에서 만들고, business_date partition overwrite와 snapshot evidence만 검증했다. Scenario 이미 아래 gold row가 있다. business_date=2026-06-29 plant-a / line-1 / gearbox-a units_produced=120 defect_count=3 나중에 같은 business_date=2026-06-29 에 대한 정정 source가 들어온다. 운영자가 원하는 것은 append가 아니다. 원하지 않는 상태: 2026-06-29 old row 2026-06-29 corrected row -> 같은 날짜 결과가 중복됨 원하는 상태: 2026-06-29 corrected row만 남음 2026-06-30 같은 다른 날짜 partition은 그대로 유지됨 재처리 전후 snapshot evidence가 남음 그래서 이 slice의 질문은 이렇다. 같은 business_date의 정정 source를 처리할 때, gold table에서 해당 날짜 partition만 중복 없이 교체하고, 어떤 run이 어떤 Iceberg snapshot을 만들었는지 남길 수 있는가? Decision Pressure Slice1의 CSV pipeline은 already-successful source를 안전하게 skip할 수 있다. dataset_id + business_date + source_hash 이 key가 같으면 같은 입력이다. 다시 계산해도 같은 결과이므로 기존 run을 재사용한다. 하지만 source_hash 가 달라졌다면 의미가 다르다. same business_date different source_hash 이건 retry가 아니라 correction이다. CSV run-folder 방식에서는 새 run output을 만들 수는 있지만, "현재 gold table에서 해당 날짜를 원자적으로 교체한다"는 table-level 의미가 약하다. Iceberg를 붙이는 이유는 여기 있다. source_hash -> 같은 입력인지 판단하는 idempotency key business_date partition -> 정정 시 교체할 gold table 범위 snapshot_id -> table commit의 evidence 즉 Spark/Iceberg는 도구 이름을 추가하려고 붙인 것이 아니라, 재처리 상태 전이를 더 명확히 표현하기 위해 붙였다. Options Option 장점 문제 판단 same source면 항상 재계산 단순함 retry 때 불필요한 commit이 계속 생김 제외 corrected source를 append 구현 쉬움 같은 날짜 gold row가 중복될 수 있음 제외 whole-table overwrite 단순함 다른 날짜 partition까지 지울 위험 제외 business_date partition overwrite correction 범위가 명확함 Spark/Iceberg 설정과 test가 필요 선택 MERGE/upsert 강력함 이번 skeleton에 과함 backlog 이번 구현은 DataFrameWriterV2.overwritePartitions() 를 사용했다. corrected_d

wide CSV 여러 개를 EAV로 모아 gold mart 만들기 현실의 데이터 소스는 한 가지 모양으로 오지 않는다. 같은 의미의 값도 어떤 파일에서는 생산수량 , 다른 파일에서는 units , 또 다른 파일에서는 made 로 올 수 있다. 온도도 어떤 곳은 섭씨, 어떤 곳은 화씨일 수 있다. 이걸 매번 pipeline code에 if source == ... 로 박기 시작하면 source가 늘 때마다 코드가 지저분해진다. manufacturing-data-platform-mini 의 EAV mini slice는 이 문제를 작게 다룬다. 여러 wide CSV를 mapping config로 표준 attribute에 맞춘 뒤, EAV long format으로 모으고, 다시 gold metric mart로 pivot/aggregate한다. 데이터는 모두 synthetic이고, 회사 코드·고객 데이터·실제 schema는 쓰지 않았다. 1. Scenario 서로 다른 공장/라인/벤더에서 비슷한 제조 지표 파일이 들어온다. 예: plant_a.csv: 설비ID, 생산수량, 불량수, 온도C, 압력kPa plant_b.csv: machine_id, output_units, defects, temp_f, pressure_bar vendor_d.csv: unit_name, made, scrap, deg_c, kpa 비즈니스적으로는 같은 지표를 보고 싶다. units_produced defect_count temperature_c pressure_kpa 문제는 source마다 column name과 unit이 다르다는 점이다. 2. Decision Pressure 단순 구현은 source마다 코드를 늘린다. if source == "plant_a": 생산수량을 units_produced로 읽는다 if source == "plant_b": output_units를 units_produced로 읽는다 temp_f를 섭씨로 변환한다 if source == "vendor_d": made를 units_produced로 읽는다 이 방식은 작게는 빨라 보이지만 source가 늘수록 문제가 된다. 새 파일 형식마다 pipeline code를 고쳐야 한다. column mapping과 transform logic이 섞인다. unit conversion이 흩어진다. quality check가 source별로 갈라진다. gold mart grain을 설명하기 어려워진다. 그래서 mapping은 config로 빼고, pipeline은 표준 attribute를 처리하게 만들었다. 3. Options option result risk source별 hard-coded parser 처음엔 빠름 source가 늘 때 code change 반복 모든 source를 wide table 하나로 합치기 보기 쉬움 sparse/heterogeneous column 폭발 EAV long format 이종 attribute를 표준 형태로 모음 pivot/quality 설계가 필요 full mapping DSL/rules engine 유연함 mini project에는 과함 이 프로젝트의 선택은 단순한 JSON mapping + EAV long + gold pivot이다. 4. Decision 각 source는 JSON config로 자신의 column을 표준 attribute에 매핑한다. source column -> standard attribute output_units -> units_produced temp_f -> temperature_c with f_to_c pressure_bar -> pressure_kpa with bar_to_kpa pipeline 흐름: wide CSVs -> mapping configs -> EAV long rows -> gold entity_daily_metrics -> quality checks -> catalog/lineage EAV row의 핵심 shape: entity_id business_date attribute value v

schema drift를 fail이 아니라 warn으로 둔 이유 데이터 파이프라인에서 source schema가 바뀌는 순간은 애매하다. 무조건 무시하면 운영자는 입력 구조가 바뀐 사실을 모른다. 반대로 모든 schema 변화를 실패로 처리하면, 정상적인 컬럼 추가까지 daily run을 막아버린다. manufacturing-data-platform-mini 에서는 이 문제를 작게 다뤘다. synthetic manufacturing CSV의 실제 header를 기준으로 schema_hash 를 만들고, previous successful run과 비교해 달라졌으면 schema_drift quality check를 warn 으로 남긴다. 단, required column이 빠져 silver/gold contract를 만들 수 없는 경우는 현재 ValueError 로 빠르게 실패한다. 1. Scenario 어느 날 source CSV에 새 컬럼이 추가된다. 기존 header: event_time,plant_id,line_id,work_order_id,machine_id,product_code, operation,units_produced,defect_count,cycle_time_ms,business_date 새 header: event_time,plant_id,line_id,work_order_id,machine_id,product_code, operation,units_produced,defect_count,cycle_time_ms,business_date,operator_id operator_id 는 아직 silver/gold mart에서 쓰지 않는다. 하지만 source 구조가 바뀐 사실은 기록되어야 한다. 2. Decision Pressure schema drift에서 중요한 질문은 단순히 "바뀌었나?"가 아니다. 바뀐 것을 운영자가 알 수 있는가? 정상적인 컬럼 추가 때문에 pipeline을 멈춰야 하는가? downstream gold mart contract가 조용히 바뀌지는 않는가? 이전 successful run과 지금 run의 schema identity를 비교할 수 있는가? 초기 구현에서는 한 가지 실제 버그가 있었다. schema_hash 가 고정된 required column 목록에 너무 묶여 있어서, 추가 컬럼이 들어와도 hash가 바뀌지 않았다. 즉 operator_id 가 추가되어도 drift가 보이지 않았다. 이 문제를 고치기 위해 read_rows 가 실제 CSV header를 반환하고, 그 실제 header 기준으로 schema_hash 를 계산하도록 바꿨다. 3. Options option result risk ignore drift pipeline은 계속 돈다 source 변화가 보이지 않음 fail every drift 변화에 강하게 반응 정상적인 컬럼 추가도 막음 warn and continue 변화가 보이고 run도 계속됨 warning을 inspect해야 함 auto-evolve silver/gold 새 컬럼을 바로 사용 가능 downstream contract가 조용히 바뀔 수 있음 full schema registry production에 가까움 mini slice에는 무거움 이 프로젝트의 선택은 warn and continue 다. 4. Decision 현재 contract는 이렇다. previous successful run이 없으면: schema_drift = pass baseline schema established current schema_hash == previous successful schema_hash: schema_drift = pass current schema_hash != previous successful schema_hash: schema_drift = warn quality_passed는 true 유지 run/lineage record에 previous/current schema_hash 저장 required column missing: V

source_hash로 같은 입력 재처리를 안전하게 skip하기 작은 데이터 파이프라인도 한 번만 실행된다고 가정하면 금방 거짓말이 된다. 실제로는 같은 파일을 다시 실행할 수 있다. 실패한 run을 재시도할 수도 있고, 과거 날짜를 backfill할 수도 있고, 운영자가 실수로 같은 입력을 다시 넣을 수도 있다. 이때 결과가 중복되면 gold metric은 더 이상 믿을 수 없다. 이 글은 개인 포트폴리오 프로젝트 manufacturing-data-platform-mini 에서 source_hash 를 이용해 같은 입력 재처리를 안전하게 skip하도록 만든 작은 설계 판단을 정리한 글이다. 데이터는 모두 synthetic이며, production platform이 아니라 검증 가능한 mini slice다. 1. Scenario 같은 business_date 의 제조/로봇 이벤트 파일을 다시 처리해야 하는 상황이 있다. 예: retry: 앞 run이 중간에 실패해서 다시 실행한다. backfill: 과거 날짜를 다시 채운다. operator mistake: 같은 파일을 실수로 다시 실행한다. 단순히 매번 append하면 같은 날짜의 gold metric이 중복될 수 있다. 2. Decision Pressure 단순 CSV pipeline은 보통 이렇게 끝난다. CSV 읽기 -> silver 만들기 -> gold 집계 -> 결과 저장 하지만 운영 관점에서는 질문이 생긴다. 이 입력은 전에 처리한 파일과 같은가? 같은 파일을 다시 돌리면 중복 output이 생기나? 다른 파일로 같은 날짜를 다시 돌리면 어떻게 구분하나? 어떤 run이 어떤 source에서 만들어졌나? 그래서 재실행을 판단할 identity가 필요했다. 3. Options option result problem always append 모든 run 결과를 계속 추가 같은 입력 재실행 시 중복 always overwrite 결과를 항상 덮어씀 이전 결과/원인 추적이 약함 skip by business_date only 같은 날짜면 무조건 skip 정정 파일을 반영할 수 없음 skip by dataset_id + business_date + source_hash 같은 입력만 no-op 정정 파일은 새 run으로 처리 가능 이 프로젝트의 Slice1은 마지막 선택지를 쓴다. 4. Decision 현재 mini pipeline은 입력 파일의 content hash를 source_hash 로 계산한다. idempotency key: dataset_id + business_date + source_hash 이미 성공한 run이 있으면 새로 처리하지 않고 기존 run을 재사용한다. same dataset_id same business_date same source_hash prior successful run exists => status = skipped 이 선택은 작지만 중요하다. 같은 파일 재실행: skip -> 중복 없음 같은 날짜의 정정 파일: source_hash가 다름 -> skip하지 않고 새 run으로 처리 가능 단, 여기서 조심해야 할 경계가 있다. Slice1은 다른 source_hash 를 새 run으로 처리할 수 있지만, 이전 gold partition을 원자적으로 교체하는 Iceberg-style overwrite까지 구현한 것은 아니다. 그 문제는 다음 Slice2의 business_date partition overwrite 주제다. 5. Evidence 관련 코드와 검증 evidence: src/manufacturing_data_platform/pipeline/lakehouse.py tests/test_lakehouse_pipeline.py VERIFICATION_LOG.md README.md 검증 로그: 2026-07-08 publication readiness check: pytest: 33 passed lakehouse JSON CLI: passed, status=processed, quality_passed=true EAV JS

Enhancing CI/CD and E2E Testing with Sentry Integration in tvview TL;DR: I integrated Sentry for error tracking and improved End-to-End (E2E) testing in the tvview project, enhancing the CI/CD pipeline. This resulted in a score increase from 85 to 95+. The Problem The tvview project lacked comprehensive error tracking and E2E testing, making it difficult to identify and resolve issues in production. The existing CI/CD pipeline needed improvement to ensure smoother deployments and better code quality. What I Tried First Initially, I focused on setting up E2E tests using Vitest, but encountered issues with the test configuration. I also attempted to integrate Sentry, but faced challenges with the DSN (Data Source Name) configuration. The Implementation Step 1: Configuring Sentry To integrate Sentry, I created separate configuration files for the client, edge runtime, and server: // sentry.client.config.ts import * as Sentry from " @sentry/nextjs " ; Sentry . init ({ dsn : " https://385038c88b6eb6ddac52d05a144ab8c1@o4511628189630464.ingest.us.sent " , // Additional configuration options }); // sentry.edge.config.ts import * as Sentry from " @sentry/nextjs " ; Sentry . init ({ dsn : " https://385038c88b6eb6ddac52d05a144ab8c1@o4511628189630464.ingest.us.sent " , // Additional configuration options }); // sentry.server.config.ts import * as Sentry from " @sentry/nextjs " ; Sentry . init ({ dsn : " https://385038c88b6eb6ddac52d05a144ab8c1@o4511628189630464.ingest.us.sentry.io " , // Additional configuration options }); Step 2: Enhancing CI/CD Pipeline I updated the .github/workflows/ci-e2e.yml file to include Sentry configuration and E2E testing: name : 📺 CI + E2E — TVView on : push : branches : [ main ] workflow_dispatch : {} schedule : - cron : " 35 6 * * *" jobs : build-and-test : runs-on : ubuntu-latest steps : - name : Checkout code uses : actions/checkout@v2 - name : Install dependencies run : npm install - name : Generate Prisma client env : DATABASE_URL : " postgre

Stop Guessing: How I Pick AI API Architecture at Every Scale I've been on both sides of this. Two years ago I was the lone backend engineer at a Series A startup, duct-taping API calls together at 2 AM because the founders wanted a chatbot demo by morning. Last quarter I sat in a procurement meeting at a Fortune 500 where we spent six weeks evaluating three vendors for a single inference workload. Same job title on LinkedIn, wildly different problems. Most AI API guides I've read treat both scenarios like they're the same conversation. They're not. The startup CTO optimizing for burn rate and the enterprise architect worrying about a 99.9% uptime SLA are solving fundamentally different equations. After enough of these conversations, I've developed a framework I'd like to share — and yes, I'll talk about Global API because it's what I actually use, but I'll also explain the reasoning behind each choice so you can adapt it to your own stack. What I Look at First: The p99 Question Before I look at price, I look at the latency distribution. Specifically, the p99. Mean latency tells you almost nothing useful. If your median response is 200ms but your p99 is 4 seconds, your users will see janky behavior on the long tail and you won't know why until production is on fire. For startups in the MVP phase, you can usually get away with best-effort routing. A p99 of 2-3 seconds is fine if you're building an async summarization feature. But the moment you put AI in the synchronous request path — like a customer-facing chatbot or a real-time code suggestion — p99 starts to bite. I learned this the hard way when our startup's "AI assistant" feature had users complaining about slowness that I couldn't reproduce locally. The culprit? Provider cold starts hitting our 1% of users who happened to get routed to a freshly spun-up instance. For enterprises, p99 isn't a nice-to-have, it's a contractual obligation. Most B2B SLAs I've negotiated pin uptime at 99.9% and require reporting on m

Enhancing CraveView's CI/CD Pipeline with Sentry and E2E Tests TL;DR: I upgraded CraveView's CI/CD pipeline by integrating Sentry for error tracking and implementing End-to-End (E2E) tests, boosting the score from 85 to 95+. This technical deep-dive explores the architecture decisions, code changes, and lessons learned. The Problem The initial problem wasn't a single error message but a series of inefficiencies in the CI/CD pipeline. The existing setup lacked comprehensive error tracking and test coverage, leading to potential issues in production. Specifically, the pipeline didn't have: Robust Error Tracking : No integrated system for capturing and analyzing errors. End-to-End Tests : Limited test coverage, which could lead to undetected issues in production. What I Tried First Initially, I focused on enhancing the test suite. I explored various testing frameworks but decided to implement E2E tests using Vitest, given its compatibility with the existing tech stack. The first approach involved setting up a basic E2E test framework. However, I encountered issues with the test environment configuration, particularly with database connectivity. The tests required a realistic database setup, which wasn't properly simulated. The Implementation Step 1: Configuring Sentry To integrate Sentry, I created configuration files for client, edge, and server initialization: sentry.client.config.ts import * as Sentry from " @sentry/nextjs " ; Sentry . init ({ dsn : " https://385038c88b6eb6ddac52d05a144ab8c1@o4511628189630464.ingest.us.sentry.io/4511629 " , // Additional config options }); sentry.edge.config.ts and sentry.server.config.ts follow a similar structure, adjusted for their respective environments. Step 2: Implementing E2E Tests I added a new test file e2e-production.test.ts in src/__tests__ : import { test , expect } from ' @playwright/test ' ; test ( ' should render the homepage ' , async ({ page }) => { await page . goto ( ' https://craveview.vercel.app ' ); await expe

Upgrading CI Workflows: From Node 20 to Node 22 and Actions v5/v6 TL;DR: I upgraded the CI workflows for the content-automation repository from Node 20 to Node 22 and Actions v5/v6, addressing compatibility issues and improving performance. Key changes included updating upload-artifact from v5 to v7 and implementing retry with backoff. The Problem The CI workflows for the content-automation repository were using Node 20 internally, despite the configuration specifying Node 20. This discrepancy caused compatibility issues with newer versions of the GitHub Actions. Specifically, the upload-artifact action was still on version 5, which was internally targeting Node 20. What I Tried First Initially, I attempted to update the upload-artifact action to version 7, which supports Node 22. However, this change alone did not resolve the issue, as other actions like checkout and setup-python were still on older versions. The Implementation To address the compatibility issues, I updated the following actions: upload-artifact from v5 to v7 checkout to v5 setup-python to v6 Here are the specific code changes: // .github/workflows/main.yml steps: - name: Checkout code uses: actions/checkout@v5 - name: Setup Python uses: actions/setup-python@v6 - name: Upload artifact uses: actions/upload-artifact@v7 Additionally, I implemented a retry mechanism with backoff for the CI workflows: // .github/workflows/main.yml steps : - name : Retry with backoff run : | for i in {1..3}; do if ./script.sh; then break else echo "Retry $i failed, backing off..." sleep $((i * 2)) fi done Key Takeaway The key takeaway from this experience is the importance of keeping CI workflows up-to-date with the latest versions of GitHub Actions. This not only ensures compatibility but also improves performance and reliability. What's Next Next, I plan to monitor the CI workflows for any issues and continue to optimize the retry mechanism for better performance. I will also explore other ways to improve the reliabili

Disallow: GPTBot is a wall. Walls don't pay rent, and the crawlers that matter most either ignore them or route around them. If your content is worth training on, the interesting question isn't "how do I keep the bots out" — it's "what do they owe me, and how do I say so in a way a machine can read." That's what RSL (Really Simple Licensing) is for. It shipped 1.0 in December 2025 with around 1,500 publishers behind it — Reddit, Yahoo, Quora, O'Reilly, Medium, Vox. This post is a from-scratch walkthrough of what the format actually is, the six places you can put it, the one mistake that makes crawlers silently ignore your terms, and where the declaration stops and enforcement begins. No tooling required to follow along — it's all plain XML and HTTP. The format is an XML vocabulary, not a config file An RSL document says: for this content, here's what's permitted, what's prohibited, and what it costs. Minimal example: <?xml version="1.0" encoding="UTF-8"?> <rsl xmlns= "https://rslstandard.org/rsl" max-age= "7" > <content url= "/" > <license> <permits type= "usage" > search </permits> <prohibits type= "usage" > ai-train </prohibits> <payment type= "crawl" > <amount currency= "USD" > 0.015 </amount> </payment> </license> </content> </rsl> Read it out loud: search engines may index this; training on it is prohibited; if you want to crawl it anyway, the rate is $0.015. usage tokens include search , ai-train , ai-use (inference/grounding), and a few more. You can scope rules by user and geo too. One rule that trips people up: prohibition wins . If the same token shows up under both permits and prohibits , the content is prohibited. Don't try to express "allowed except for X" by listing X in both — just prohibit X. The namespace is the thing crawlers actually key on The single most common way to publish RSL that quietly does nothing: getting the namespace wrong. It must be exactly: xmlns="https://rslstandard.org/rsl" http instead of https , a trailing slash, or a plausible

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