Which is cheaper, Claude Fable 5.1 and GLM-5.3-Flash?

GLM-5.3-Flash has the lowest input price. Per 1M input tokens: Claude Fable 5.1 from $10.00 and GLM-5.3-Flash from $0.07.

Which has the larger context window, Claude Fable 5.1 and GLM-5.3-Flash?

GLM-5.3-Flash has the largest context window: Claude Fable 5.1 1,000,000 tokens and GLM-5.3-Flash 1,310,720 tokens.

Which is better for coding, Claude Fable 5.1 and GLM-5.3-Flash?

Claude Fable 5.1 scores highest on the Artificial Analysis Coding Index: Claude Fable 5.1 79.1 and GLM-5.3-Flash 71.5.

Which is smarter, Claude Fable 5.1 and GLM-5.3-Flash?

Claude Fable 5.1 scores highest on the Artificial Analysis Intelligence Index: Claude Fable 5.1 51.2 and GLM-5.3-Flash 41.8.

Can I switch between Claude Fable 5.1 and GLM-5.3-Flash without changing my code?

Yes. All of them are served through FastRouter's OpenAI-compatible API, so switching is a change of the model parameter (anthropic/claude-fable-5.1, z-ai/glm-5.3-flash).

Claude Fable 5.1 vs GLM-5.3-Flash

Side-by-side pricing per provider, context window, benchmark scores and speed, all on one OpenAI-compatible API.

Claude Fable 5.1 Anthropicanthropic/claude-fable-5.1

GLM-5.3-Flash Z.aiz-ai/glm-5.3-flash

Creator

Anthropic

Z.ai

Released

Sep 1, 2026

Aug 26, 2026

Context window

1.31M

Max output

128K

131K

Input / 1MLowest provider price

$10.00

$0.07$0.07–$0.15 across 5

Output / 1MLowest provider price

$50.00

$0.25$0.25–$0.50 across 5

Providers

IntelligenceArtificial Analysis index

51.2

41.8

CodingArtificial Analysis index

79.1

71.5

Accepts

Text, Image, Files

Text, Image, Video

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

Claude Fable 5.1 vs GLM-5.3-Flash: summary

Claude Fable 5.1 and GLM-5.3-Flash are both available through FastRouter's OpenAI-compatible API, so switching between them is a change of model id, not a new integration.

Claude Fable 5.1, from Anthropic, has a 1,000,000-token context window, costs $10.00/1M input and $50.00/1M output tokens and scores 51.2 on the Artificial Analysis Intelligence Index.

GLM-5.3-Flash, from Z.ai, has a 1,310,720-token context window, costs from $0.07/1M input and $0.25/1M output tokens across 5 providers and scores 41.8 on the Artificial Analysis Intelligence Index.

GLM-5.3-Flash is the cheapest on input, 143× cheaper than the next model, GLM-5.3-Flash has the largest context window, Claude Fable 5.1 scores highest for intelligence and Claude Fable 5.1 leads on coding.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="anthropic/claude-fable-5.1", messages=[...]) # or client.chat.completions.create(model="z-ai/glm-5.3-flash", messages=[...])

Full API docs

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More comparisons

Benchmark scores sourced from ArtificialAnalysis