Model comparison

Claude Opus 4.8 vs GLM 5.3 Flash

Anthropic's Claude Opus 4.8 against Z.ai's GLM 5.3 Flash: vendor list prices, limits, abilities and the Artificial Analysis indexes side by side - and what OpenSmartRoute does when both are available.

CheaperGLM 5.3 Flash

GLM 5.3 Flash lists at $0.237 per million tokens blended against $10 for Claude Opus 4.8 - 42x less.

Intelligence: levelEven

Intelligence index 42 against 42: within a point of each other.

Stronger on codingClaude Opus 4.8

Claude Opus 4.8 scores 74 on the coding index against 72 - 3 points apart.

Stronger on agenticGLM 5.3 Flash

GLM 5.3 Flash scores 51 on the agentic index against 42 - 9 points apart.

Longer contextGLM 5.3 Flash

GLM 5.3 Flash reads 1.0M tokens at once, Claude Opus 4.8 1M.

Abilities differGLM 5.3 Flash

only GLM 5.3 Flash offers open weights.

NewerGLM 5.3 Flash

GLM 5.3 Flash was released about 3 months later.

Side by side

Vendor list prices per million tokens and published limits; indexes are Artificial Analysis composites (0-100).

Specification	Claude Opus 4.8	GLM 5.3 Flash
Input price / 1M tokens	$5.00	$0.15
Output price / 1M tokens	$25.0	$0.50
Blended (3 in : 1 out)	$10.0	$0.24
Cached input / 1M	$0.50	$0.03
Context window	1M	1.0M
Max output	128K	944K
Input	text, image, file	text, image, video
Output	text	text
Tool calls
Structured output
Reasoning
Open weights
Intelligence index	42	42
Coding index	74	72
Agentic index	42	51
Released	May 27, 2026	Aug 26, 2026
Available on this deployment

What a month costs

List price times tokens for three typical workloads; your mix of input and output decides which model's pricing suits you.

Workload	Claude Opus 4.8	GLM 5.3 Flash	Difference
Support chat20M tokens in, 5M out a month - a help desk answering a few thousand conversations.	$225	$5.50	$220 less on GLM 5.3 Flash
Document summaries100M in, 5M out - long inputs, short answers.	$625	$17.50	$608 less on GLM 5.3 Flash
Coding assistant60M in, 20M out - a team's editor assistant, output-heavy.	$800	$19.00	$781 less on GLM 5.3 Flash

What the router does with the pair

The two measure the same on the intelligence index, so the router treats them as peers and lets price, observed latency and your outcomes decide: GLM 5.3 Flash wins on cost, and a few bad outcomes on either move the next requests to the other.

Price a request Playground

yaml

# targets.yaml - both models as routing targets (metadata.model links each to the catalogue entry)
targets:
  - { id: glm-5.3-flash, kind: llm, metadata: { model: z-ai/glm-5.3-flash } }
  - { id: claude-opus-4.8, kind: llm, metadata: { model: anthropic/claude-opus-4.8 } }

# rules.yaml - the cheaper model by default, the stronger one when the request is hard
rules:
  - name: simple-requests-stay-cheap
    when: { max_complexity: 0.45 }
    prefer: [glm-5.3-flash]
    weight: 0.8
  - name: hard-requests-escalate
    when: { min_complexity: 0.45 }
    prefer: [claude-opus-4.8]
    weight: 0.8

Frequently asked

Is Claude Opus 4.8 cheaper than GLM 5.3 Flash?: No. Claude Opus 4.8 lists at $5.00 in / $25.0 out per million tokens, GLM 5.3 Flash at $0.15 in / $0.50 out; blended, GLM 5.3 Flash is the cheaper one.
Which is better, Claude Opus 4.8 or GLM 5.3 Flash?: The two measure the same on the intelligence index, so the task, the price and the abilities decide.
Which has the longer context window?: GLM 5.3 Flash - 1.0M tokens against 1M.
Can I use Claude Opus 4.8 and GLM 5.3 Flash together?: Yes. Declare both as targets and OpenSmartRoute picks one per request on quality for the task, price and your rules - the cheaper model for the requests it can answer, the stronger one for the rest - and records why in the trace.

Also compared

Every Anthropic and Z.ai model, with prices, is on the vendor pages; the rankings show what the router actually picks.

For the business

What it means for which models you pay for.

Catalogue of every vendor
The right model, not the famous one
Price, context, abilities and benchmark indexes side by side, with the model that fits each task named.
The rankings
89% less
Lower cost per request
On the 150-prompt benchmark the router spent 89% less than sending every prompt to the reference model, and the judged quality went up, not down.
Read the benchmark
Per million tokens, every model
Prices you can compare
The catalogue prints input and output prices and what three typical monthly workloads cost on each.
The model catalogue

Which LLM is the cheapest for our workload?: The best-for pages rank the live catalogue per task by the index that measures it, and the router picks the cheapest model that meets your quality rule for each request.
How much can we save on our LLM bill?: On the public benchmark the router saved 89% against sending everything to the reference model. Import last month's provider bill on the bill page and the estimate is computed on your own traffic before you change a line of code.
How often do model prices change?: The catalogue is refreshed from the vendors' price lists; each model page shows the date of its data.

Stop choosing between Claude Opus 4.8 and GLM 5.3 Flash. Route to both.

Declare the pair as targets and OpenSmartRoute picks per request - the cheaper one where it holds up, the stronger one where it matters - with the comparison in every trace.

Create a free account Try a request

Free plan, no card. Fifteen thousand decisions a month with the full trace.

Specification

Claude Opus 4.8

GLM 5.3 Flash

Input price / 1M tokens

$5.00

$0.15

Output price / 1M tokens

$25.0

$0.50

Blended (3 in : 1 out)

$10.0

$0.24

Cached input / 1M

$0.50

$0.03

Context window

1.0M

Max output

128K

944K

Input

text, image, file

text, image, video

Output

text

Tool calls

Structured output

Reasoning

Open weights

Intelligence index

Coding index

Agentic index

Released

May 27, 2026

Aug 26, 2026

Available on this deployment

Workload

Claude Opus 4.8

GLM 5.3 Flash

Difference

Support chat20M tokens in, 5M out a month - a help desk answering a few thousand conversations.

$225

$5.50

$220 less on GLM 5.3 Flash

Document summaries100M in, 5M out - long inputs, short answers.

$625

$17.50

$608 less on GLM 5.3 Flash

Coding assistant60M in, 20M out - a team's editor assistant, output-heavy.

$800

$19.00

$781 less on GLM 5.3 Flash

# targets.yaml - both models as routing targets (metadata.model links each to the catalogue entry) targets: - { id: glm-5.3-flash, kind: llm, metadata: { model: z-ai/glm-5.3-flash } } - { id: claude-opus-4.8, kind: llm, metadata: { model: anthropic/claude-opus-4.8 } } # rules.yaml - the cheaper model by default, the stronger one when the request is hard rules: - name: simple-requests-stay-cheap when: { max_complexity: 0.45 } prefer: [glm-5.3-flash] weight: 0.8 - name: hard-requests-escalate when: { min_complexity: 0.45 } prefer: [claude-opus-4.8] weight: 0.8

Frequently asked

Is Claude Opus 4.8 cheaper than GLM 5.3 Flash?

No. Claude Opus 4.8 lists at $5.00 in / $25.0 out per million tokens, GLM 5.3 Flash at $0.15 in / $0.50 out; blended, GLM 5.3 Flash is the cheaper one.

Which is better, Claude Opus 4.8 or GLM 5.3 Flash?

The two measure the same on the intelligence index, so the task, the price and the abilities decide.

Which has the longer context window?

GLM 5.3 Flash - 1.0M tokens against 1M.

Can I use Claude Opus 4.8 and GLM 5.3 Flash together?

Yes. Declare both as targets and OpenSmartRoute picks one per request on quality for the task, price and your rules - the cheaper model for the requests it can answer, the stronger one for the rest - and records why in the trace.

Claude Opus 4.8 vs GLM 5.3 Flash

Side by side

What a month costs

What the router does with the pair

Frequently asked

Also compared

What it means for which models you pay for.

The right model, not the famous one

Lower cost per request

Prices you can compare

Stop choosing between Claude Opus 4.8 and GLM 5.3 Flash. Route to both.

Claude Opus 4.8 vs GLM 5.3 Flash

Side by side

What a month costs

What the router does with the pair

Frequently asked

Also compared

What it means for which models you pay for.

The right model, not the famous one

Lower cost per request

Prices you can compare

Stop choosing between Claude Opus 4.8 and GLM 5.3 Flash. Route to both.