Qwen3.5 Flash 02.23

OpenRouter

1000K context$0.10/M input$0.40/M output

1453peak 1464

Avg Score

63.2

Avg Cost

$0.06

Score/$

1037.2

Runs

121

Win/Loss/Draw

Scoring Dimensions

Score Distribution

Category ELOs

multi-languagehard

2051

code-reviewmedium

1650

multi-language

1616

debuggingexpert

1589

code-review

1586

backendexpert

1570

backendeasy

1562

frontendmedium

1551

frontendexpert

1539

full-stackmedium

1538

debugging

1484

backend

1481

backendhard

1476

from-scratcheasy

1474

frontend

1466

debuggingmedium

1455

from-scratchexpert

1449

backendmedium

1442

from-scratchmedium

1435

full-stack

1433

debugginghard

1427

frontendhard

1386

full-stackhard

1379

code-reviewhard

1367

refactoringmedium

1288

refactoring

1280

from-scratch

1228

multi-languageexpert

1227

frontendeasy

1142

from-scratchhard

855

refactoringexpert

329

All Results

Task	Category	Score	Duration	Cost
Add caching layer to eliminate slow SSR page loads	full-stack	78.9	37.4s	<$0.01
Build CLI tool with subcommands and config	from-scratch	29.9	12m 52s	$0.05
Add rate limiting middleware	backend	72.2	47.6s	<$0.01
Debug race condition in worker pool	debugging	83.6	9.6s	<$0.01
Add retry logic and dead letter queue to Python task queue	backend	79.9	1m 2s	<$0.01
Add i18n with locale routing to Next.js app	full-stack	62.6	13m 48s	$0.06
Fix flaky test suite	debugging	88.3	19.6s	<$0.01
Build distributed node cluster with gossip protocol	from-scratch	24.2	1m 29s	<$0.01
Fix Node.js stream backpressure causing OOM on large files	backend	85.7	19.2s	<$0.01
Fix N+1 query in dashboard	backend	47.8	18.4s	<$0.01
Fix 12 WCAG accessibility violations in checkout form	frontend	77.5	1m 7s	<$0.01
Fix hallucination and context window bugs in RAG agent	backend	19.8	2m 56s	$0.01
Fix data integrity bugs in denormalized e-commerce schema	debugging	82.3	58.0s	<$0.01
Build real-time portfolio risk calculator	backend	42.9	2m 15s	<$0.01
Add slash commands and moderation to Discord bot	backend	69.0	33.8s	<$0.01
Build codebase indexer for LLM context windows	from-scratch	34.8	1m 44s	<$0.01
Optimize slow Postgres queries in Flask app	backend	78.0	56.6s	<$0.01
Build REST API from scratch	from-scratch	71.7	22.3s	<$0.01
Debug and fix 6 broken database triggers and constraints	debugging	75.7	1m 25s	<$0.01
Add file upload with S3 presigned URLs	backend	77.3	32.2s	$0.01
Fix auth bypass vulnerability	debugging	88.8	28.6s	<$0.01
Fix deadlocking transaction patterns in Flask app	backend	70.2	30.2s	<$0.01
Port Python CLI to Rust	multi-language	46.7	11m 3s	$0.04
Build MCP server for database management	backend	77.3	43.3s	<$0.01
Add WebSocket real-time updates	full-stack	66.4	26.5s	$0.01
Build SaaS admin dashboard from scratch	from-scratch	35.3	3m 16s	$0.01
Build terminal UI dashboard	from-scratch	48.5	1m 2s	<$0.01
Fix broken GitHub Actions CI pipeline	debugging	76.1	29.2s	$0.01
Fix broken responsive layout	frontend	64.2	42.3s	$0.01
Fix race conditions in order matching engine	backend	78.7	53.4s	<$0.01
Optimize bloated React bundle under 500KB	frontend	73.1	1m 23s	<$0.01
Implement transformer inference engine with KV cache	from-scratch	74.3	13m 30s	$0.03
Convert React app to PWA with offline support	frontend	79.7	53.3s	<$0.01
Find and patch all OWASP Top 10 vulnerabilities	debugging	65.5	1m 21s	<$0.01
Add streaming SSE endpoint for LLM chat	backend	80.8	34.7s	$0.01
Write tests for untested legacy Flask service	code-review	42.8	12m 27s	$0.06
Implement zero-trust API authentication layer	backend	70.6	1m 18s	<$0.01
Add cursor-based pagination to REST API	backend	76.1	30.2s	$0.01
Implement JWT auth middleware	backend	50.5	20.0s	<$0.01
Add virtual scrolling to table rendering 5000 rows	frontend	78.7	26.3s	$0.01
Fix React hydration mismatch	frontend	77.2	28.8s	$0.01
Dockerize Node.js monorepo	full-stack	62.0	34.5s	<$0.01
Build production website with auth and members area	frontend	60.5	5m 15s	$0.02
Add Google OAuth2 login to Express app	full-stack	67.0	43.4s	$0.01
Replace console.log with structured logging	refactoring	43.2	1m 6s	$0.01
Implement background job scheduler with persistence	backend	31.1	1m 30s	<$0.01
Build RAG pipeline with vector search	backend	49.3	45.1s	<$0.01
Add Redis caching layer to Express API	backend	77.3	1m 2s	$0.01
Refactor monolithic handler to CQRS	refactoring	36.5	43.6s	$0.01
Code review: identify security vulns	code-review	47.4	47.4s	$0.01
Build materialized view refresh pipeline for analytics	backend	73.8	1m 35s	<$0.01
Implement multi-tenant row-level security in Postgres	backend	41.0	14m 1s	$0.06
Implement Stripe webhook handler	backend	82.5	11m 41s	$0.04
Write complex SQL report with window functions	backend	59.5	1m 34s	<$0.01
Build LLM evaluation harness with structured grading	backend	53.5	1m 54s	<$0.01
Migrate callback-hell Express app to async/await	refactoring	53.9	1m 36s	$0.01
Write Kubernetes manifests for Node.js microservice	full-stack	72.8	1m 10s	<$0.01
Split 1100-line god file into proper modules	refactoring	51.4	1m 25s	<$0.01
Fix memory leak in event handler	debugging	83.3	28.2s	$0.01
Remove AI slop and over-engineering from codebase	refactoring	74.3	30.8s	<$0.01
Write integration tests for payment flow	code-review	74.1	2m 3s	$0.02
Add GraphQL layer over REST API	multi-language	82.4	41.6s	$0.01
Harden insecure Docker setup with 12 vulnerabilities	code-review	74.0	27.6s	<$0.01
Zero-downtime schema migration	full-stack	68.1	17.9s	<$0.01
Find and fix 4 hidden backdoors in Flask app	debugging	58.1	43.7s	<$0.01
Migrate callback-hell Express app to async/await	refactoring	74.7	1m 30s	$0.21
Code review: identify security vulns	code-review	75.8	32.1s	$0.03
Implement transformer inference engine with KV cache	from-scratch	76.4	19.7s	$0.03
Add virtual scrolling to table rendering 5000 rows	frontend	47.8	35.4s	$0.06
Fix 12 WCAG accessibility violations in checkout form	frontend	67.5	59.8s	$0.07
Port Python CLI to Rust	multi-language	58.8	52.7s	$0.07
Add WebSocket real-time updates	full-stack	66.0	53.4s	$0.10
Implement JWT auth middleware	backend	82.2	44.6s	$0.06
Split 1100-line god file into proper modules	refactoring	51.0	3m 10s	$0.77
Build codebase indexer for LLM context windows	from-scratch	29.6	1m 50s	$0.14
Implement zero-trust API authentication layer	backend	66.4	43.1s	$0.06
Write Kubernetes manifests for Node.js microservice	full-stack	92.0	21.3s	$0.06
Implement multi-tenant row-level security in Postgres	backend	67.2	30.0s	$0.03
Remove AI slop and over-engineering from codebase	refactoring	80.3	1m 14s	$0.28
Add i18n with locale routing to Next.js app	full-stack	32.9	52.8s	$0.09
Add caching layer to eliminate slow SSR page loads	full-stack	79.3	52.0s	$0.10
Optimize bloated React bundle under 500KB	frontend	69.3	36.0s	$0.09
Replace console.log with structured logging	refactoring	26.3	42.4s	$0.05
Fix broken responsive layout	frontend	67.2	34.9s	$0.04
Find and patch all OWASP Top 10 vulnerabilities	debugging	70.0	2m 1s	$0.11
Convert React app to PWA with offline support	frontend	65.0	1m 10s	$0.12
Harden insecure Docker setup with 12 vulnerabilities	code-review	90.8	12.7s	<$0.01
Add streaming SSE endpoint for LLM chat	backend	67.3	1m 4s	$0.08
Dockerize Node.js monorepo	full-stack	65.8	33.7s	$0.10
Add retry logic and dead letter queue to Python task queue	backend	54.0	7m 18s	$0.09
Fix N+1 query in dashboard	backend	50.5	54.7s	$0.04
Write tests for untested legacy Flask service	code-review	65.5	3m 39s	$0.15
Fix memory leak in event handler	debugging	69.2	7m 22s	$0.20
Build distributed node cluster with gossip protocol	from-scratch	23.3	2m 14s	$0.13
Add rate limiting middleware	backend	44.8	1m 17s	$0.04
Build CLI tool with subcommands and config	from-scratch	24.8	1m 47s	$0.11
Fix hallucination and context window bugs in RAG agent	backend	61.9	2m 47s	$0.24
Implement background job scheduler with persistence	backend	23.1	51.3s	$0.05
Build terminal UI dashboard	from-scratch	58.9	1m 12s	$0.07
Optimize slow Postgres queries in Flask app	backend	83.6	24.9s	$0.04
Build REST API from scratch	from-scratch	68.7	49.0s	$0.07
Find and fix 4 hidden backdoors in Flask app	debugging	76.4	1m 35s	$0.19
Add slash commands and moderation to Discord bot	backend	27.5	2m 16s	$0.13
Refactor monolithic handler to CQRS	refactoring	22.9	1m 23s	$0.10
Fix auth bypass vulnerability	debugging	81.3	1m 51s	$0.26
Debug and fix 6 broken database triggers and constraints	debugging	85.7	46.8s	$0.06
Build SaaS admin dashboard from scratch	from-scratch	39.2	1m 9s	$0.11
Write integration tests for payment flow	code-review	72.0	1m 29s	$0.23
Build RAG pipeline with vector search	backend	33.6	1m 18s	$0.14
Build real-time portfolio risk calculator	backend	29.0	1m 21s	$0.23
Fix race conditions in order matching engine	backend	85.5	30.1s	$0.08
Zero-downtime schema migration	full-stack	72.4	42.1s	$0.06
Write complex SQL report with window functions	backend	70.1	2m 28s	$0.16
Build LLM evaluation harness with structured grading	backend	57.6	2m 11s	$0.17
Build production website with auth and members area	frontend	56.6	3m 16s	$0.25
Build MCP server for database management	backend	74.8	49.0s	$0.06
Fix data integrity bugs in denormalized e-commerce schema	debugging	77.0	22.1s	$0.05
Fix flaky test suite	debugging	85.6	3m 30s	$0.12
Build materialized view refresh pipeline for analytics	backend	70.5	1m 44s	$0.10
Fix deadlocking transaction patterns in Flask app	backend	87.9	23.0s	$0.04
Debug race condition in worker pool	debugging	62.7	16.3s	$0.05