Skip to content
Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed
  1. Home
  2. Best For
  3. System Design

Best AI for System Design

Here is a collaborative editor architecture. Find what breaks. Also a startup teardown and a training-cost estimate made without search.

Updated Jun 2026·3 challenges·20 models

How System Design rankings are computed

20 models tested across 3 system design challenges.Composite score: 30% Rival Index, 20% task coverage, 20% challenge-scoped duel performance, 15% recency, 15% tier. Deduplicated by product line. Claude Haiku 4.5 leads at 77.3/100. Drawn from Rival's open dataset of 21,000+ human preference votes.

Rival's Pick·#46 Rival Index·Anthropic flagship

Too close to call
Claude Haiku 4.5
Claude Haiku 4.5anthropic

Neck and neck with Gemini 3.8 Flash. Claude Haiku 4.5 gets the nod on blind votes. Rising fast but not yet battle-tested in community votes.

Composite scores combine task evidence, Rival Index, recency, and model tier. Rival’s Pick is a separate editorial recommendation. How ranking works

Gemini 3.8 Flash
Gemini 3.8 Flash
google
$0.75·$3.75
75Composite
Claude Haiku 4.5
Claude Haiku 4.5
anthropic
$1.00·$5.00
77Composite
Gemini 2.5 Pro Preview 06-05
Gemini 2.5 Pro Preview 06-05
google
$1.25·$10.00
75Composite

Head-to-Head

Claude Haiku 4.5 logo
Claude Haiku 4.5
vs
Gemini 3.8 Flash
Gemini 3.8 Flash logo
Claude Haiku 4.5 logo
Claude Haiku 4.5
vs
Gemini 2.5 Pro Preview 06-05
Gemini 2.5 Pro Preview 06-05 logo
Gemini 3.8 Flash logo
Gemini 3.8 Flash
vs
Gemini 2.5 Pro Preview 06-05
Gemini 2.5 Pro Preview 06-05 logo

What the top three actually wrote

Opening lines from 6 answers across every prompt behind this ranking. Formatting stripped, words untouched.

Estimate Complexity

Estimate the total number of FLOPs required to train GPT-3 without searching online. Explain your reasoning step by step.

Claude Haiku 4.5207 words
Estimating GPT-3 Training FLOPs I'll work through this from first principles using publicly known GPT-3 specs. Known Parameters Model size: 175 billion parameters Training tokens: ~300 billion tokens (estimated from OpenAI's hints about compute) Training approach: Standard transformer with dense attention Step 1: FLOPs…
Read the full answer
Gemini 2.5 Pro Preview 06-05664 words
Of course. Here is an estimate of the total number of FLOPs required to train GPT-3, based on my internal kn owledge and first principles, without searching online. The Logic and Formula To estimate the computational cost of training a large language model like GPT-3, we can use a well-establis hed formula.
Read the full answer

Startup Pitch Teardown

Here's a pitch deck summary for a startup called "MindMeld AI": **Slide 1 - Vision:** "We're building the future of human-AI collaboration.…

Claude Haiku 4.5583 words
Three Weakest Claims in MindMeld AI Pitch "94% accuracy" with zero context on what that means Why it's weak: Accuracy is meaningless without specifying the task.
Read the full answer
Gemini 3.8 Flash712 words
Here are the three weakest claims in the MindMeld AI pitch deck, along with the rationale and concrete recommendations to fix them. The Core Scientific Feasibility Claim The Claim (Slides 1 & 3): “Predict what you want to type before you think it” and “Proprietary EEG headband uses advanced ML to decode neural patterns…
Read the full answer

Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

Gemini 3.8 Flash1,282 words
This architecture contains several catastrophic flaws that will cause silent data corruption, severe database exhaustion, high latency, and security vulnerabilities. Here is the breakdown of every failure mode, race condition, and scaling bottleneck, along with proposed solutions and trade-offs.
Read the full answer
Gemini 2.5 Pro Preview 06-051,344 words
Of course. This is a great exercise. The proposed architecture has several critical flaws that would prevent it from functioning as a reliable, real-time collaborative editor at scale. Here is a breakdown of the issues, categorized for clarity.
Read the full answer

Full Rankings

20 models
#
Model
Coverage
Index
Price
Composite
4
GPT OSS 120B logo
GPT OSS 120Bopenai
3/3
#129
$0.18·$0.80
74
5
Qwen3.6 27B logo
Qwen3.6 27Bqwen
3/3
#1
$0.33·$3.25
74
6
Gemini 3.1 Pro Preview logo
Gemini 3.1 Pro Previewgoogle
3/3
#7
$2.00·$12.00
73
7
Claude Fable 5 logo
Claude Fable 5anthropic
3/3
#12
$10.00·$50.00
72
8
GPT-6 Luna logo
GPT-6 Lunaopenai
2/3
$0.10·$0.50
71
9
Gemma 4 26B A4B logo
Gemma 4 26B A4Bgoogle
3/3
#28
$0.13·$0.40
71
10
GLM 5.3 Prime logo
GLM 5.3 Primez-ai
2/3
$2.80·$8.80
71
Challenges3
Estimate Complexity
A Fermi estimate out loud. The reasoning is graded, not the number.
Startup Pitch Teardown
A pitch taken apart. Charitable is not the assignment.
Debug This Architecture
A broken system. Thoroughness has no ceiling here.
Related
Code ReviewComplex ReasoningAPI Documentation

Keep exploring

#1 VS #2

Claude Haiku 4.5 vs Gemini 3.8 Flash

The top two for System Design, compared directly

RELATED

Best AI for Code Review

See which models rank highest here

Rival
How it worksPrivacyTerms
Explore all of Rival

Explore

  • Compare Models
  • All Models
  • Image Comparison
  • Audio Comparison
  • Image Generation
  • Best AI For...
  • Arena
  • API Pricing
  • Challenges

Discover

  • SubjectiveBench
  • Default Index
  • Research
  • Research downloads
  • Rival Kits
  • Find your AI taste
  • UI Glow-Up
  • VoiceLock
  • Cost Cutter
  • Agent skills
  • Benchmarks vs Vibes
  • Brief
  • Jailbreak
  • Model Updates
  • Provider Status
  • AI Creators

Connect

  • Methodology
  • Advertise
  • Partnerships
  • Privacy Policy
  • Terms
  • RSS Feed