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Head-to-head comparison

Seed 2.1 Turbo vs GLM 5.3

Seed 2.1 Turbo (ByteDance Seed) and GLM 5.3 (Z.ai) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 10 September 2026

As of 10 September 2026, GLM 5.3 holds the stronger ModelCap Index position (#8 vs #18); Seed 2.1 Turbo is 1.8× cheaper per output token ($2.50/1M vs $4.40/1M); and GLM 5.3 offers the longer context window (1.3M vs 262K tokens).

Which should you choose?

Choose Seed 2.1 Turbo if…

  • API cost matters — $2.50/1M output tokens against $4.40/1M, about 1.8× cheaper.
  • your workload is prompt-heavy — input tokens cost $0.50/1M against $1.40/1M.

Choose GLM 5.3 if…

  • you want the stronger overall ModelCap Index position — #8 against #18 (82.3 vs 76.8 points).
  • you need the longer context window — 1.3M tokens against 262K.
  • you want provider choice — 27 listed API providers against 1.
  • you want the more recently listed model — GLM 5.3 was listed 18 August 2026, Seed 2.1 Turbo 12 August 2026.

Seed 2.1 Turbo vs GLM 5.3: specs, pricing and context

Specification comparison of Seed 2.1 Turbo and GLM 5.3
FieldSeed 2.1 TurboByteDance SeedGLM 5.3Z.ai
ModelCap Index position#18#8
Index score76.882.3
EvidenceEstimatedMeasured
Input price / 1M tokens$0.50$1.40
Output price / 1M tokens$2.50$4.40
Context window262K tokens1.3M tokens
Max output tokens236K944K
API providers listed127
Weight accessAPI onlyRestricted license
Input modalitiesText, Image, VideoText
First listed12 August 202618 August 2026
PublisherByteDance SeedZ.ai

Evidence: global-corpus-prior over 185 held-out anchors (12%); launch card against 2 resolved peers on 3 rows (88%); exceeds every named peer on 1 of 3 rows; no cross-lab optimism probe available; shrunk 3.1 toward the measured corpus · 4 public benchmark observations across 4 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Seed 2.1 Turbo vs GLM 5.3

Public benchmark boards where Seed 2.1 Turbo or GLM 5.3 has a published result
BoardSeed 2.1 TurboGLM 5.3Leads
Arena codingArena (LMArena)—15281514–1541MaxOnly one result
LMArena AgentLMArena—2.6%1.9%–3.2%MaxOnly one result
AA Intelligence IndexArtificial Analysis—44.9intelligence-index:v4.3:maxOnly one result
AA Terminal-Bench 2.1Artificial Analysis—83.9%terminal-bench:2.1:terminus-2:e2b:pass-at-1:3-repeats:source-model="GLM-5.3 (max)":reasoning=trueOnly one result
AA Humanity's Last ExamArtificial Analysis—42.3%hle:may-2025:text-only-2158:no-tools:pass-at-1:source-model="GLM-5.3 (max)":reasoning=trueOnly one result
Terminal-Bench 4.0Terminal-Bench (Laude Institute)—41.8%38.6%–45.1%Claude Code · MaxOnly one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Seed 2.1 Turbo vs GLM 5.3: common questions

Is Seed 2.1 Turbo better than GLM 5.3?

GLM 5.3 ranks higher on the ModelCap Index as of 10 September 2026: #8 against #18. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.

Is Seed 2.1 Turbo cheaper than GLM 5.3?

Seed 2.1 Turbo is cheaper on output tokens: $2.50/1M against $4.40/1M. Input tokens are $0.50/1M for Seed 2.1 Turbo and $1.40/1M for GLM 5.3. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $2.25 for Seed 2.1 Turbo versus $5.00 for GLM 5.3. Seed 2.1 Turbo costs 55.0% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

Which has the bigger context window, Seed 2.1 Turbo or GLM 5.3?

GLM 5.3 has the larger context window: 1.3M tokens against 262K.

Which is better for coding, Seed 2.1 Turbo or GLM 5.3?

The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.

Are Seed 2.1 Turbo and GLM 5.3 open-weight models?

Seed 2.1 Turbo: API only. GLM 5.3: Restricted license. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.

Where can I run Seed 2.1 Turbo and GLM 5.3?

ModelCap currently lists 1 API provider for Seed 2.1 Turbo and 27 for GLM 5.3, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Seed 2.1 Turbo vs GLM 5.3 comparison?

Every figure comes from the sealed ModelCap dataset published 10 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.

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