Head-to-head comparison

Claude Opus 5.5 vs. GLM-5.3-Flash

Compare published benchmark results from matching versions and cohorts, API pricing, and technical specifications. Any documented test setup differences remain visible.

shared result series: 188
distinct benchmarks: 21
latest retrieval: 2026-10-15

First modelSecond model

Specifications

General specifications

Release date, availability, context window, architecture, and published parameter counts at a glance. Undisclosed details remain marked as unavailable.

Specifications for Claude Opus 5.5 and GLM-5.3-Flash
Attribute	Claude Opus 5.5	GLM-5.3-Flash
Provider	Anthropic	Z.ai
Released	Sep 22, 2026	Aug 26, 2026
Availability	Active	Open Source
Model type	Proprietary	Open Weights
Parameters	Not published	320B, 18B active
Architecture	Not published	Mixture of Experts
Context window	1,000,000 tokens	1,000,000 tokens
Knowledge cutoff	June 2026	Not published
Technical sources	Model	Model, Context

Pricing

API pricing compared

The table compares official standard API rates per 1M tokens, including published cache pricing. Batch, fast, priority, regional surcharges, tool calls, and cloud platform pricing are excluded.

API pricing for Claude Opus 5.5 and GLM-5.3-Flash
Price type	Claude Opus 5.5	GLM-5.3-Flash
API input	$4	$0.15
API output	$20	$0.5
Cache read	$0.2	$0.03
Cache write (5 min.)	$5	Not listed
Cache write (1 hr.)	$8	Not listed
Price verified	09/22/2026 Source	09/22/2026 Source

Claude Opus 5.5GLM-5.3-Flash

API inputUSD per 1M tokens, base tier

Claude Opus 5.5$4

GLM-5.3-Flash$0.15

API outputUSD per 1M tokens, base tier

Claude Opus 5.5$20

GLM-5.3-Flash$0.5

Cache readUSD per 1M tokens, base tier

Claude Opus 5.5$0.2

GLM-5.3-Flash$0.03

Key to the marks:better valuebetter, but not conclusivetie

Pricing by provider

Direct developer pricing and provider endpoint tariffs routed through OpenRouter are listed separately. Prices are in USD per 1M tokens. Context-dependent direct tiers plus regional, Flex, Priority, and other OpenRouter tariffs remain individually identifiable.

Provider pricing for Claude Opus 5.5 and GLM-5.3-Flash
Model	Provider	Purchase route and tariff	Input per 1M tokens	Output per 1M tokens	Source
Claude Opus 5.5	Anthropic	Direct from developerStandard API	Lowest listed price: $4	Lowest listed price: $20	Source09/22/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock	Lowest listed price: $4	Lowest listed price: $20	Source10/17/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock/eu-west-1	$4.4	$22	Source10/17/2026
	Amazon Bedrock	Via OpenRouteramazon-bedrock/us-east-1	$4.4	$22	Source10/17/2026
	Anthropic	Via OpenRouteranthropic	Lowest listed price: $4	Lowest listed price: $20	Source10/17/2026
	Anthropic	Via OpenRouteranthropic/fast	$8	$40	Source10/17/2026
	Azure	Via OpenRouterazure/global	Lowest listed price: $4	Lowest listed price: $20	Source10/17/2026
	Azure	Via OpenRouterazure/us	$4.4	$22	Source10/17/2026
	Claude Platform on AWS	Via OpenRouterclaude-on-aws	Lowest listed price: $4	Lowest listed price: $20	Source10/17/2026
	Google	Via OpenRoutergoogle-vertex/europe	$4.4	$22	Source10/17/2026
	Google	Via OpenRoutergoogle-vertex/global	Lowest listed price: $4	Lowest listed price: $20	Source10/17/2026
	Google	Via OpenRoutergoogle-vertex/us	$4.4	$22	Source10/17/2026
GLM-5.3-Flash	Z.ai	Direct from developerStandard API	$0.15	$0.5	Source09/22/2026
	BaseTen	Via OpenRouterbaseten/fp8	$0.15	$0.5	Source10/17/2026
	BaseTen	Via OpenRouterbaseten/fp8/us	$0.15	$0.5	Source10/17/2026
	CoreWeave	Via OpenRoutercoreweave/nvfp4	$0.15	$0.5	Source10/17/2026
	Crusoe	Via OpenRoutercrusoe/fp4	$0.15	$0.5	Source10/17/2026
	Decart	Via OpenRouterdecart/fp4	$0.0885	$0.295	Source10/17/2026
	DeepInfra	Via OpenRouterdeepinfra/fp4	$0.075	$0.25	Source10/17/2026
	DigitalOcean	Via OpenRouterdigitalocean	$0.1312	$0.4375	Source10/17/2026
	Fireworks	Via OpenRouterfireworks	$0.15	$0.5	Source10/17/2026
	Friendli	Via OpenRouterfriendli	$0.15	$0.5	Source10/17/2026
	GMICloud	Via OpenRoutergmicloud/fp8	$0.09	$0.3	Source10/17/2026
	Inceptron	Via OpenRouterinceptron/fp8	$0.1	$0.69	Source10/17/2026
	InferenceNet	Via OpenRouterinference-net/fp4	$0.12	$0.388	Source10/17/2026
	Makora	Via OpenRoutermakora	$0.14	$0.47	Source10/17/2026
	Modal	Via OpenRoutermodal/nvfp4	$0.15	$0.5	Source10/17/2026
	Morph	Via OpenRoutermorph/fp8	$0.05	$0.65	Source10/17/2026
	Near AI	Via OpenRouternear-ai/fp8	$0.08	$0.5	Source10/17/2026
	NextBit	Via OpenRouternextbit/fp4	$0.25	$0.7	Source10/17/2026
	Novita	Via OpenRouternovita/fp8	$0.084	$0.28	Source10/17/2026
	OpenInference	Via OpenRouteropen-inference/fp4	Lowest listed price: $0.0123	Lowest listed price: $0.2	Source10/17/2026
	Parasail	Via OpenRouterparasail/fast	$0.1875	$0.625	Source10/17/2026
	Parasail	Via OpenRouterparasail/fp4	$0.15	$0.5	Source10/17/2026
	Phala	Via OpenRouterphala/nvfp4	$0.1275	$0.425	Source10/17/2026
	Reka	Via OpenRouterreka	$0.06	$1.6	Source10/17/2026
	Relace	Via OpenRouterrelace	$0.075	$0.5	Source10/17/2026
	Sail Research	Via OpenRoutersail-research/fp4	$0.0784	$0.3	Source10/17/2026
	Sail Research	Via OpenRoutersail-research/us	$0.0784	$0.3	Source10/17/2026
	SiliconFlow	Via OpenRoutersiliconflow/fp8	$0.15	$0.5	Source10/17/2026
	StreamLake	Via OpenRouterstreamlake/fp8	$0.075	$0.25	Source10/17/2026
	Together	Via OpenRoutertogether	$0.15	$0.5	Source10/17/2026
	Venice	Via OpenRoutervenice	$0.15	$0.5	Source10/17/2026
	Wafer	Via OpenRouterwafer/nvfp4	$0.12	$0.5	Source10/17/2026
	Z.AI	Via OpenRouterz-ai/fp8	$0.15	$0.5	Source10/17/2026

Performance

Shared benchmarks

Only published results with the same benchmark version, task, metric, and comparison cohort are paired. Different reasoning levels, agents, harnesses, or output limits appear directly in the table.

Capability profile from matched benchmarks

Each axis averages directly matched benchmark families. A value of 100 means the stronger value within this pair, not a universal quality score.

Not enough directly matched categories for a reliable radar

Only 0 of at least 5 categories have comparable, direct model measurements. The benchmark tables below show the available evidence without filling missing axes.

Claude Opus 5.5GLM-5.3-Flash

Code MigrationOverall. Higher is better. Test setup not documented as identical

Claude Opus 5.566.646 %

GLM-5.3-Flash20.515 %

CyberBench v1.1Overall. Higher is better. Test setup not documented as identical

Claude Opus 5.555.357 %

GLM-5.3-Flash67.857 %

EMBOverall. Higher is better. Test setup not documented as identical

Claude Opus 5.575.938 %

GLM-5.3-Flash55.932 %

Finance Agent (v2)Overall. Higher is better. Test setup not documented as identical

Claude Opus 5.558.587 %

GLM-5.3-Flash57.85 %

Harvey's Legal Agent BenchmarkOverall · Task fully resolved. Higher is better. Test setup not documented as identical

Claude Opus 5.53.75 %

GLM-5.3-Flash6.667 %

IOIOverall. Higher is better. Test setup not documented as identical

Claude Opus 5.595.056 %

GLM-5.3-Flash52.5 %

Legal Research BenchOverall · All-pass. Higher is better. Test setup not documented as identical

Claude Opus 5.550.481 %

GLM-5.3-Flash45.192 %

LMArena Code Arena WebDevOverall. Higher is better. Test setup not documented as identical

Claude Opus 5.51,811.149

GLM-5.3-Flash1,606.051

LMArena Text, Style ControlOverall. Higher is better. Test setup not documented as identical

Claude Opus 5.51,508.083

GLM-5.3-Flash1,474.228

LMArena Vision, Style ControlOverall. Higher is better. Test setup not documented as identical

Claude Opus 5.51,292.688

GLM-5.3-Flash1,273.331

MedScribeOverall. Higher is better. Test setup not documented as identical

Claude Opus 5.591.43 %

GLM-5.3-Flash88.936 %

ProgramBenchOverall. Higher is better. Test setup not documented as identical

Claude Opus 5.518.5 %

GLM-5.3-Flash0 %

Key to the marks:better valuebetter, but not conclusivetie

Benchmark scores for Claude Opus 5.5 and GLM-5.3-Flash
Benchmark and task	Claude Opus 5.5	GLM-5.3-Flash	Source
Code MigrationOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value66.646 %	20.515 %	Vals AI Source details Data as of: 10/12/2026
CyberBench v1.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	55.357 %	Higher measured value67.857 %	Vals AI Source details Data as of: 10/12/2026
EMBOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value75.938 %	55.932 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value58.587 %	57.85 %	Vals AI Source details Data as of: 10/12/2026
Harvey's Legal Agent BenchmarkOverall · Task fully resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: task resolution rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	3.75 %	Higher measured value6.667 %	Vals AI Source details Data as of: 10/12/2026
IOIOverall Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value95.056 %	52.5 %	Vals AI Source details Data as of: 10/14/2026
Legal Research BenchOverall · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value50.481 %	45.192 %	Vals AI Source details Data as of: 10/12/2026
LMArena Code Arena WebDevOverall Test details Test setup not documented as identicalNo direct winnerVersion: webdevMetric: WebDev Arena Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-max, Reasoning: max, Harness: Arena Code Arena WebDev GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Code Arena WebDevClaude Opus 5.5: Arena rating from 2,597 published pairwise votes.GLM-5.3-Flash: Arena rating from 16,470 published pairwise votes.	Higher measured value1,811.149 95% confidence interval: ±14.586The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,606.051 95% confidence interval: ±6.732The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Text, Style ControlOverall Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-high, Reasoning: high, Harness: Arena Text, style control GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Text, style controlClaude Opus 5.5: Arena rating from 7,687 published pairwise votes.GLM-5.3-Flash: Arena rating from 31,379 published pairwise votes.	Higher measured value1,508.083 95% confidence interval: ±7.535The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,474.228 95% confidence interval: ±4.913The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Vision, Style ControlOverall Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-high, Reasoning: high, Harness: Arena Vision, style control GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Vision, style controlClaude Opus 5.5: Arena rating from 2,508 published pairwise votes.GLM-5.3-Flash: Arena rating from 11,157 published pairwise votes.	Higher measured value1,292.688 95% confidence interval: ±12.73The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,273.331 95% confidence interval: ±7.077The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
MedScribeOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 30,000 tokens	Higher measured value91.43 %	88.936 %	Vals AI Source details Data as of: 10/13/2026
ProgramBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully resolved rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value18.5 %	0 %	Vals AI Source details Data as of: 10/12/2026
ProofBenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value100 %	21 %	Vals AI Source details Data as of: 10/12/2026
SRE BenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully solved rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value33.588 %	0.763 %	Vals AI Source details Data as of: 10/14/2026
Tax Agent BenchOverall Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value45.573 %	31.55 %	Vals AI Source details Data as of: 10/12/2026
Terminal-Bench 2.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: high, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value87.64 %	62.921 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0Overall Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value65.152 %	37.374 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceOverall Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Harness: Mini-SWE-agent, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value47.143 %	2.857 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexOverall Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: weighted index scoreScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value66.972 %	44.581 %	Vals AI Source details Data as of: 10/13/2026
Vibe Code Bench 1-100Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1.0Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: xhigh, Harness: OpenHands, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Harness: OpenHands, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value30.361 %	16.033 %	Vals AI Source details Data as of: 10/14/2026
Vibe Code Bench v1.1Overall Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Harness: OpenHands, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Harness: OpenHands, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value90.294 %	30.759 %	Vals AI Source details Data as of: 10/12/2026
Code MigrationCLI Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value65.528 %	7.354 %	Vals AI Source details Data as of: 10/12/2026
CyberBench v1.1Patch Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	No direct winner85.714 %	No direct winner85.714 %	Vals AI Source details Data as of: 10/12/2026
EMBComps Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value76.405 %	44.602 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Adjustments Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value54.528 %	53.193 %	Vals AI Source details Data as of: 10/12/2026
Harvey's Legal Agent BenchmarkAntitrust Competition · Criteria passed Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: criteria pass rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	82.246 %	Higher measured value86.594 %	Vals AI Source details Data as of: 10/12/2026
IOIIOI 2024 Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value100 %	53.167 %	Vals AI Source details Data as of: 10/14/2026
Legal Research BenchAdministrative / Regulatory · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value65.152 %	57.576 %	Vals AI Source details Data as of: 10/12/2026
LMArena Code Arena WebDevImage to webdev Test details Test setup not documented as identicalNo direct winnerVersion: webdevMetric: WebDev Arena Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-max, Reasoning: max, Harness: Arena Code Arena WebDev GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Code Arena WebDevClaude Opus 5.5: Arena rating from 493 published pairwise votes.GLM-5.3-Flash: Arena rating from 4,315 published pairwise votes.	Higher measured value1,748.511 95% confidence interval: ±30.162The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,580.658 95% confidence interval: ±10.006The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
LMArena Text, Style ControlBusiness, management and finance Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-high, Reasoning: high, Harness: Arena Text, style control GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Text, style controlClaude Opus 5.5: Arena rating from 1,370 published pairwise votes.GLM-5.3-Flash: Arena rating from 5,788 published pairwise votes.	Higher measured value1,492.054 95% confidence interval: ±16.446The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,470.347 95% confidence interval: ±8.428The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Vision, Style ControlCreative writing vision Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-high, Reasoning: high, Harness: Arena Vision, style control GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Vision, style controlClaude Opus 5.5: Arena rating from 219 published pairwise votes.GLM-5.3-Flash: Arena rating from 941 published pairwise votes.	Higher measured value1,301.035 95% confidence interval: ±42.823The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,249.947 95% confidence interval: ±20.348The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
ProgramBenchAlmost Resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: almost-resolved rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value65 %	7 %	Vals AI Source details Data as of: 10/12/2026
SRE BenchCapability Score Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: capability scoreScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value53.562 %	6.489 %	Vals AI Source details Data as of: 10/14/2026
Tax Agent BenchControversy & Precedence Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value30 %	10 %	Vals AI Source details Data as of: 10/12/2026
Terminal-Bench 2.1Easy Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: high, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value100 %	91.667 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0Hardware Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value60 %	20 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceEarth Sciences Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Harness: Mini-SWE-agent, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value37.5 %	0 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexCode Migration Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: benchmark scoreScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value68.901 %	20.185 %	Vals AI Source details Data as of: 10/13/2026
Code MigrationCOBOL Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value70 %	60 %	Vals AI Source details Data as of: 10/12/2026
CyberBench v1.1PoC Test details Test setup not documented as identicalNo direct winnerVersion: 1.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	25 %	Higher measured value50 %	Vals AI Source details Data as of: 10/12/2026
EMBDataroom Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value84.873 %	65.712 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)All-Pass Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value48.111 %	46.259 %	Vals AI Source details Data as of: 10/12/2026
Harvey's Legal Agent BenchmarkAntitrust Competition · Task fully resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: task resolution rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	No direct winner0 %	No direct winner0 %	Vals AI Source details Data as of: 10/12/2026
IOIIOI 2025 Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value100 %	56.667 %	Vals AI Source details Data as of: 10/14/2026
Legal Research BenchAdministrative / Regulatory · Weighted partial credit Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: weighted partial-credit scoreScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	85.427 %	Higher measured value90.822 %	Vals AI Source details Data as of: 10/12/2026
LMArena Code Arena WebDevWebdev Test details Test setup not documented as identicalNo direct winnerVersion: webdevMetric: WebDev Arena Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-max, Reasoning: max, Harness: Arena Code Arena WebDev GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Code Arena WebDevClaude Opus 5.5: Arena rating from 2,597 published pairwise votes.GLM-5.3-Flash: Arena rating from 16,470 published pairwise votes.	Higher measured value1,811.149 95% confidence interval: ±14.586The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,606.051 95% confidence interval: ±6.732The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Text, Style ControlChinese Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-high, Reasoning: high, Harness: Arena Text, style control GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Text, style controlClaude Opus 5.5: Arena rating from 704 published pairwise votes.GLM-5.3-Flash: Arena rating from 2,386 published pairwise votes.	Higher measured value1,574.432 95% confidence interval: ±22.751The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,530.199 95% confidence interval: ±12.82The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Vision, Style ControlDiagram Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-high, Reasoning: high, Harness: Arena Vision, style control GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Vision, style controlClaude Opus 5.5: Arena rating from 589 published pairwise votes.GLM-5.3-Flash: Arena rating from 2,680 published pairwise votes.	Higher measured value1,324.12 95% confidence interval: ±25.101The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,306.092 95% confidence interval: ±12.014The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
ProgramBenchFully Resolved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully resolved rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value18.5 %	0 %	Vals AI Source details Data as of: 10/12/2026
SRE BenchFully Solved Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: fully solved rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value33.588 %	0.763 %	Vals AI Source details Data as of: 10/14/2026
Tax Agent BenchControversy & Precedence Analysis Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value66.871 %	52.416 %	Vals AI Source details Data as of: 10/12/2026
Terminal-Bench 2.1Hard Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: high, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value81.111 %	38.889 %	Vals AI Source details Data as of: 09/28/2026
Terminal-Bench 4.0Media Test details Test setup not documented as identicalNo direct winnerVersion: 4.0Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	Higher measured value75 %	25 %	Vals AI Source details Data as of: 10/13/2026
Terminal-Bench ScienceEngineering Sciences Test details Test setup not documented as identicalNo direct winnerVersion: 0.1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Harness: Mini-SWE-agent, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Harness: Mini-SWE-agent, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value22.222 %	0 %	Vals AI Source details Data as of: 10/14/2026
Vals IndexEMB Test details Test setup not documented as identicalNo direct winnerVersion: 2.1Metric: benchmark scoreScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value75.938 %	55.932 %	Vals AI Source details Data as of: 10/13/2026
Code MigrationCode Quality Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: mean reviewer code-quality ratingScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value4.541 / 5	4.355 / 5	Vals AI Source details Data as of: 10/12/2026
EMBDCF Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value70.139 %	59.852 %	Vals AI Source details Data as of: 10/12/2026
Finance Agent (v2)Comparables Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	45.756 %	Higher measured value45.936 %	Vals AI Source details Data as of: 10/12/2026
Harvey's Legal Agent BenchmarkArbitration International Dispute Resolution · Criteria passed Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: criteria pass rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 131,072 tokens	82.969 %	Higher measured value89.606 %	Vals AI Source details Data as of: 10/12/2026
IOIIOI 2026 Test details Test setup not documented as identicalNo direct winnerVersion: 2Metric: accuracyScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value85.167 %	47.667 %	Vals AI Source details Data as of: 10/14/2026
Legal Research BenchBusiness & Commercial · All-pass Test details Test setup not documented as identicalNo direct winnerVersion: 1Metric: all-pass rateScoring: Higher is betterClaude Opus 5.5: Compute: max, Temperature: 1, Output limit: 128,000 tokens GLM-5.3-Flash: Reasoning: max, Temperature: 1, Top P: 0.95, Output limit: 128,000 tokens	Higher measured value48.837 %	44.186 %	Vals AI Source details Data as of: 10/12/2026
LMArena Code Arena WebDevWebdev-html Test details Test setup not documented as identicalNo direct winnerVersion: webdevMetric: WebDev Arena Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-max, Reasoning: max, Harness: Arena Code Arena WebDev GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Code Arena WebDevClaude Opus 5.5: Arena rating from 122 published pairwise votes.GLM-5.3-Flash: Arena rating from 2,445 published pairwise votes.	Higher measured value1,762.971 95% confidence interval: ±64.035The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,578.09 95% confidence interval: ±13.732The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Text, Style ControlCoding Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-high, Reasoning: high, Harness: Arena Text, style control GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Text, style controlClaude Opus 5.5: Arena rating from 1,755 published pairwise votes.GLM-5.3-Flash: Arena rating from 8,116 published pairwise votes.	Higher measured value1,545.148 95% confidence interval: ±14.437The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,525.054 95% confidence interval: ±7.559The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/13/2026
LMArena Vision, Style ControlEnglish Test details Test setup not documented as identicalNo direct winnerVersion: style-control-v1Metric: style-controlled Bradley-Terry ratingScoring: Higher is betterClaude Opus 5.5: Snapshot: claude-opus-5.5-high, Reasoning: high, Harness: Arena Vision, style control GLM-5.3-Flash: Snapshot: glm-5.3-flash, Harness: Arena Vision, style controlClaude Opus 5.5: Arena rating from 818 published pairwise votes.GLM-5.3-Flash: Arena rating from 3,514 published pairwise votes.	Higher measured value1,286.241 95% confidence interval: ±21.812The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	1,273.799 95% confidence interval: ±11.253The Arena score measures human preference rather than a fixed capability test. The confidence interval, Arena category, and model configuration are part of the result.	LMArena Source details Data as of: 10/09/2026
Key to the marks:better valuebetter, but not conclusivetie

Our model tests

Our tests

SVG short test

One SVG prompt and fixed output settings. Captures are shown only with 0 reported reasoning tokens or documented lack of reasoning controls. Identical test conditions do not make the models' internal compute identical.

Shared test round: 4ae5d8eeb9a9

Claude Opus 5.5

Unavailable in this round

GLM-5.3-Flash

Unavailable in this round

Earlier tests

Pelican on a bicycle

A community classic for free-form SVG drawing.

Claude Opus 5.5

Reasoning (requested): high

Current attempt

Run date: Oct 1, 2026
API provider: openrouter
Requested API model: anthropic/claude-opus-5.5
API model reported in response: anthropic/claude-opus-5.5
Reasoning setting: high
Pinned endpoint: Anthropic | anthropic/claude-opus-5.5-20260921
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Passed, not a quality rating
Response time: 33.2 s

Visually reviewed. This individual test does not establish overall model quality.

GLM-5.3-Flash

Reasoning (requested): high

Current attempt

Run date: Oct 1, 2026
API provider: openrouter
Requested API model: z-ai/glm-5.3-flash
API model reported in response: z-ai/glm-5.3-flash
Reasoning setting: high
Pinned endpoint: Z.AI | z-ai/glm-5.3-flash-20260826
Temperature: Provider default
Token limit including reasoning: 8,192 tokens
Test protocol: community-visual-tests-v1
Technical checks: Passed, not a quality rating
Response time: 49.7 s

Visually reviewed. This individual test does not establish overall model quality.

Earlier attempts (1)

Sep 7, 2026API request failedReasoning setting: high

Prompt and test conditions

Generate an SVG of a pelican riding a bicycle

Token limit including reasoning: 8,192 tokens

Task origin (Simon Willison)

How to read this comparison

Winning one benchmark is not an overall verdict

Your workload, budget, and required context length matter most. A coding benchmark says little about visual understanding or agent performance.

The standard price table uses direct developer rates. The provider comparison labels OpenRouter endpoints, regions, and special tariffs separately.

Every result links to its measurement source and retrieval date. Labels distinguish vendor reports, official benchmark leaderboards, and independent evaluations. Disputed or archived results are excluded.

More matchups

Compare Claude Opus 5.5 and GLM-5.3-Flash with other leading models using the same data and benchmark logic.

View the complete LLM comparison

Claude Opus 5.5 vs. GLM-5.3-Flash

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General specifications

API pricing compared

Shared benchmarks

Capability profile from matched benchmarks

Our tests

SVG short test

Claude Opus 5.5

GLM-5.3-Flash

Pelican on a bicycle

Winning one benchmark is not an overall verdict

Related LLM comparisons