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Qwen3.5 Flash 02.23
OpenRouter
1000K context$0.10/M input$0.40/M output
1341peak 1357
Avg Score
64.5
Avg Cost
$0.02
Score/$
4107.4
Runs
65
Win/Loss/Draw
Scoring Dimensions
Score Distribution
Category ELOs
multi-languagehard
1954frontendmedium
1535multi-language
1521debuggingmedium
1519backendmedium
1484code-reviewhard
1455debugging
1441frontend
1438debugginghard
1435frontendhard
1435backendeasy
1419debuggingexpert
1415backend
1380backendhard
1315from-scratchexpert
1311backendexpert
1283full-stackhard
1265full-stack
1251code-review
1249full-stackmedium
1185code-reviewmedium
1161multi-languageexpert
1115frontendexpert
1114from-scratch
1109from-scratcheasy
1106refactoring
1092refactoringmedium
1084frontendeasy
904from-scratchhard
872from-scratchmedium
794refactoringexpert
210All Results
| Task | Category | Score |
|---|---|---|
| Add caching layer to eliminate slow SSR page loads | full-stack | 78.9 |
| Build CLI tool with subcommands and config | from-scratch | 32.7 |
| Add rate limiting middleware | backend | 72.2 |
| Debug race condition in worker pool | debugging | 83.6 |
| Add retry logic and dead letter queue to Python task queue | backend | 79.9 |
| Add i18n with locale routing to Next.js app | full-stack | 62.6 |
| Fix flaky test suite | debugging | 88.3 |
| Build distributed node cluster with gossip protocol | from-scratch | 30.6 |
| Fix Node.js stream backpressure causing OOM on large files | backend | 85.7 |
| Fix N+1 query in dashboard | backend | 47.8 |
| Fix 12 WCAG accessibility violations in checkout form | frontend | 77.5 |
| Fix hallucination and context window bugs in RAG agent | backend | 19.8 |
| Fix data integrity bugs in denormalized e-commerce schema | debugging | 82.3 |
| Build real-time portfolio risk calculator | backend | 42.9 |
| Add slash commands and moderation to Discord bot | backend | 69.0 |
| Build codebase indexer for LLM context windows | from-scratch | 34.8 |
| Optimize slow Postgres queries in Flask app | backend | 78.0 |
| Build REST API from scratch | from-scratch | 71.7 |
| Debug and fix 6 broken database triggers and constraints | debugging | 75.7 |
| Add file upload with S3 presigned URLs | backend | 77.3 |
| Fix auth bypass vulnerability | debugging | 88.8 |
| Fix deadlocking transaction patterns in Flask app | backend | 70.2 |
| Port Python CLI to Rust | multi-language | 46.7 |
| Build MCP server for database management | backend | 77.3 |
| Add WebSocket real-time updates | full-stack | 66.4 |
| Build SaaS admin dashboard from scratch | from-scratch | 35.3 |
| Build terminal UI dashboard | from-scratch | 52.5 |
| Fix broken GitHub Actions CI pipeline | debugging | 76.1 |
| Fix broken responsive layout | frontend | 64.2 |
| Fix race conditions in order matching engine | backend | 78.7 |
| Optimize bloated React bundle under 500KB | frontend | 73.1 |
| Implement transformer inference engine with KV cache | from-scratch | 74.3 |
| Convert React app to PWA with offline support | frontend | 79.7 |
| Find and patch all OWASP Top 10 vulnerabilities | debugging | 65.5 |
| Add streaming SSE endpoint for LLM chat | backend | 80.8 |
| Write tests for untested legacy Flask service | code-review | 42.8 |
| Implement zero-trust API authentication layer | backend | 70.6 |
| Add cursor-based pagination to REST API | backend | 76.1 |
| Implement JWT auth middleware | backend | 50.5 |
| Add virtual scrolling to table rendering 5000 rows | frontend | 78.7 |
| Fix React hydration mismatch | frontend | 77.2 |
| Dockerize Node.js monorepo | full-stack | 62.0 |
| Build production website with auth and members area | frontend | 60.5 |
| Add Google OAuth2 login to Express app | full-stack | 67.0 |
| Replace console.log with structured logging | refactoring | 43.2 |
| Implement background job scheduler with persistence | backend | 31.1 |
| Build RAG pipeline with vector search | backend | 49.3 |
| Add Redis caching layer to Express API | backend | 77.3 |
| Refactor monolithic handler to CQRS | refactoring | 36.5 |
| Code review: identify security vulns | code-review | 47.4 |
| Build materialized view refresh pipeline for analytics | backend | 73.8 |
| Implement multi-tenant row-level security in Postgres | backend | 41.0 |
| Implement Stripe webhook handler | backend | 82.5 |
| Write complex SQL report with window functions | backend | 59.5 |
| Build LLM evaluation harness with structured grading | backend | 53.5 |
| Migrate callback-hell Express app to async/await | refactoring | 53.9 |
| Write Kubernetes manifests for Node.js microservice | full-stack | 72.8 |
| Split 1100-line god file into proper modules | refactoring | 51.4 |
| Fix memory leak in event handler | debugging | 83.3 |
| Remove AI slop and over-engineering from codebase | refactoring | 74.3 |
| Write integration tests for payment flow | code-review | 72.0 |
| Add GraphQL layer over REST API | multi-language | 82.4 |
| Harden insecure Docker setup with 12 vulnerabilities | code-review | 74.0 |
| Zero-downtime schema migration | full-stack | 68.1 |
| Find and fix 4 hidden backdoors in Flask app | debugging | 58.1 |