Which is cheaper, GPT-6.1 Terra and GLM-5.3-Flash?

GLM-5.3-Flash has the lowest input price. Per 1M input tokens: GPT-6.1 Terra from $1.00 and GLM-5.3-Flash from $0.07.

Which has the larger context window, GPT-6.1 Terra and GLM-5.3-Flash?

GLM-5.3-Flash has the largest context window: GPT-6.1 Terra 1,050,000 tokens and GLM-5.3-Flash 1,310,720 tokens.

Which is smarter, GPT-6.1 Terra and GLM-5.3-Flash?

GPT-6.1 Terra scores highest on the Artificial Analysis Intelligence Index: GPT-6.1 Terra 51.0 and GLM-5.3-Flash 27.8.

Can I switch between GPT-6.1 Terra 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 (openai/gpt-6.1-terra, z-ai/glm-5.3-flash).

GPT-6.1 Terra vs GLM-5.3-Flash

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

Estimate monthly cost for these models

GPT-6.1 Terra OpenAIopenai/gpt-6.1-terra

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

Creator

OpenAI

Z.ai

Released

Oct 26, 2026

Aug 26, 2026

Context window

1.05M

1.31M

Max output

128K

131K

Input / 1MLowest provider price

$1.00

$0.07$0.07–$0.15 across 5

Output / 1MLowest provider price

$5.00

$0.25$0.25–$0.50 across 5

Providers

IntelligenceArtificial Analysis index

51.0

27.8

Accepts

Text, Image, Files

Text, Image, Video

Produces

Text

Tool calling

Yes

Structured output

Yes

Reasoning

Yes

GPT-6.1 Terra vs GLM-5.3-Flash: summary

GPT-6.1 Terra 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.

GPT-6.1 Terra, from OpenAI, has a 1,050,000-token context window, costs $1.00/1M input and $5.00/1M output tokens and scores 51.0 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 27.8 on the Artificial Analysis Intelligence Index.

GLM-5.3-Flash is the cheapest on input, 14× cheaper than the next model, GLM-5.3-Flash has the largest context window and GPT-6.1 Terra scores highest for intelligence.

Switch with one line

client = OpenAI(base_url="https://api.fastrouter.ai/api/v1", api_key="<FASTROUTER_API_KEY>") client.chat.completions.create(model="openai/gpt-6.1-terra", messages=[...]) # or client.chat.completions.create(model="z-ai/glm-5.3-flash", messages=[...])

Full API docs

Frequently asked questions

More comparisons

Benchmark scores sourced from ArtificialAnalysis