Model comparison
GLM 5.3 Flash vs GPT-5.6 Terra
Z.ai against OpenAI, compared on context, price, and verified benchmark results.
Catalog record checked September 3, 2026Individual provider fields may changeEvidence confidence: High — see receipts below
Z.ai
GLM 5.3 Flash
Balanced · Open weights
OpenAI
GPT-5.6 Terra
Balanced
| Specification | GLM 5.3 Flash | GPT-5.6 Terra |
|---|---|---|
| Provider | Z.ai | OpenAI |
| Tier | Balanced | Balanced |
| Context window | 1.05M | Winner: 1.05M |
| Max output | Winner: 131K | 128K |
| Input / 1M tokens | Winner: $0.15 | $2 |
| Output / 1M tokens | Winner: $0.50 | $12 |
| Weights | Open | Closed |
| Parameters | 320B total / 18B active (MoE) | mid-tier reasoning model |
| Reasoning levels | Not verifiedUnverified | none, low, medium, high, xhigh, max |
| Modalities | text, image, video | text, image |
| License | MIT | Not disclosedUnverified |
| API model id | Not publishedUnverified | gpt-5.6-terra |
| Released | August 26, 2026 | July 9, 2026 |
| Artificial Analysis Intelligence Index (2026-08-26) | 57 | Not verifiedUnverified |
| Artificial Analysis Intelligence Index [high] (2026-08-14) | Not verifiedUnverified | 50 |
| SWE-bench Verified (2026-09-01) | 92 | Winner: 95.4 |
| Terminal-Bench 2.1 (2026-08) | 84.3 | Winner: 87.4 |
| DeepSWE 1.1 (2026-08) | 63.4 | Not verifiedUnverified |
| Humanity's Last Exam (2026-08) | 55.3 | Not verifiedUnverified |
| LiveBench (2026-09-05) | Not verifiedUnverified | 77.9 |
Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.
Benchmark receipts
- 2026-09-05: LiveBench official leaderboard (benchmark-owned), max effortContamination-resistant general capability across reasoning, coding, math, data analysis, and language, with monthly question refreshes. Comparability: comparable with caveat — Rolling question set: observations months apart measure different question mixes. Record the measurement date and compare within ~1 month windows.
- 2026-09-01: vals.ai SWE-bench Verified leaderboard (independent, mini-swe-agent bash-only) (independent; official SWE-bench not published)Real GitHub issue resolution: does the model's patch pass the hidden tests. Comparability: comparable with caveat — Post-audit vendor claims and pre-audit scores sit on different task trust levels; scaffolding (agent harness, compute budget) also dominates results. Never aggregate across scaffolds.
- 2026-08-14: Artificial AnalysisComposite index blending reasoning, knowledge, and coding evals into one 0–100 score. Comparability: directly comparable — AA occasionally rebaselines the index scale between snapshots — a score captured on one date is only comparable to same-snapshot scores (check measuredAt).
- 2026-08: Z.ai GLM-5.3-Flash blog (vendor, mini-swe-agent, 400K context)Agentic software engineering: pass@1 on real repo tasks with reported cost per completed task. Comparability: directly comparable
- 2026-08: GLM-5.3-Flash HF model card (vendor, with tools, full set)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.
- 2026-07-09: OpenAI GPT-5.6 announcement (vendor; chart transcribed by Vellum)Agentic terminal work: multi-step tasks executed in a sandboxed shell environment. Comparability: comparable with caveat — Scores across Terminal-Bench major versions (v1 vs v2) are NOT comparable; harness configuration (container, time limits) also shifts results.
Pricing tiers: GLM 5.3 Flash: $0.15/$0.50 per MTok is the standard first-party and third-party rate (Z.ai docs; GMI, Novita, Together). A 50% promo tier runs $0.075/$0.25 — confirm which rate your account quotes. · GPT-5.6 Terra: Launch list was $2.50/$15; cut to $2/$12 on 2026-07-30. Cached input $0.20/MTok; batch $1/$6.
GLM 5.3 Flash
GLM 5.3 Flash is Z.ai's natively multimodal open-weight workhorse — 1M context, hybrid sparse/linear attention, near-flagship Intelligence Index at a fraction of the cost.
Best for
- Cost-efficient long-context
- Multimodal input
- Coding agents
Watch out
Self-hosting needs ~186GB GPU memory at 4-bit (multi-GPU). Third-party hosts charge more than Z.ai's own API.
GPT-5.6 Terra
GPT-5.6 Terra delivers roughly GPT-5.5-class quality at about half the cost, with the full 1.05M-token context.
Best for
- Cost-sensitive production
- Mixed reasoning workloads
- High-volume agents
Watch out
Quality trails Sol on the hardest tasks; route frontier work to Sol when it matters.
When the cheaper one wins
GLM 5.3 Flash is cheaper on output at $0.50 per million tokens against $12 for GPT-5.6 Terra — about 24×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.
Run the model pickerEvidence confidence: High
How strong and complete the evidence behind this comparison is — not a prediction of which model is better.
- Pricing verified on both sides — Input and output rates are verified for both models.
- 4/5 core specs verified on both sides — Not published for at least one side: reasoning levels.
- 3 shared named benchmarks with differing scores — Measured on: Artificial Analysis Intelligence Index, SWE-bench Verified, Terminal-Bench 2.1.
- Verified within the last 90 days — Newest catalog check was 8 days ago.
- Both models carry source citations — Each side has at least two catalog sources on record.
Source receipts
Each catalog figure was checked against the provider or an independent second source on the date shown.
- GLM 5.3 Flash: Z.ai — GLM-5.3-Flash announcement (accessed 2026-08-29)
- GLM 5.3 Flash: getdeploying — GLM-5.3-Flash reference (accessed 2026-08-29)
- GLM 5.3 Flash: GMI Cloud — GLM-5.3-Flash analysis (accessed 2026-08-29)
- GPT-5.6 Terra: OpenAI — GPT-5.6 (accessed 2026-08-29)
- GPT-5.6 Terra: OpenAI API pricing (gpt-5.6-terra $2/$12) (accessed 2026-08-29)
Related comparisons
- Gemini 3.7 Flash vs GLM 5.3 Flash
- Amazon Nova 2 Pro vs GLM 5.3 Flash
- Amazon Nova 2 Pro vs GPT-5.6 Terra
- Claude Sonnet 5 vs GLM 5.3 Flash
- Claude Sonnet 5 vs GPT-5.6 Terra
- Cohere Command A+ vs GLM 5.3 Flash
Diving deeper on one model? GLM 5.3 Flash · GPT-5.6 Terra
Common questions
GLM 5.3 Flash vs GPT-5.6 Terra
Answered from the verified figures on this page rather than general guidance.
Is GLM 5.3 Flash or GPT-5.6 Terra cheaper for input?
GLM 5.3 Flash is cheaper at $0.15 per million input tokens, against $2 for GPT-5.6 Terra — roughly 13× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; GLM 5.3 Flash has tiered pricing: $0.15/$0.50 per MTok is the standard first-party and third-party rate (Z.ai docs; GMI, Novita, Together). A 50% promo tier runs $0.075/$0.25 — confirm which rate your account quotes. GPT-5.6 Terra has tiered pricing: Launch list was $2.50/$15; cut to $2/$12 on 2026-07-30. Cached input $0.20/MTok; batch $1/$6.
Is GLM 5.3 Flash or GPT-5.6 Terra cheaper for output?
GLM 5.3 Flash is cheaper at $0.50 per million output tokens, against $12 for GPT-5.6 Terra — roughly 24× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; GLM 5.3 Flash has tiered pricing: $0.15/$0.50 per MTok is the standard first-party and third-party rate (Z.ai docs; GMI, Novita, Together). A 50% promo tier runs $0.075/$0.25 — confirm which rate your account quotes. GPT-5.6 Terra has tiered pricing: Launch list was $2.50/$15; cut to $2/$12 on 2026-07-30. Cached input $0.20/MTok; batch $1/$6.
Which has the larger context window, GLM 5.3 Flash or GPT-5.6 Terra?
Both accept about 1.05M tokens of context, so document length will not decide between them.
Should I use GLM 5.3 Flash or GPT-5.6 Terra?
Both sit in the balanced tier, so the choice usually comes down to price and context rather than capability. GLM 5.3 Flash suits cost-efficient long-context; GPT-5.6 Terra suits cost-sensitive production.
Can I self-host GLM 5.3 Flash or GPT-5.6 Terra?
GLM 5.3 Flash publishes open weights, but self-hosting and third-party provider access depend on the licence, hardware, serving support, and availability. GPT-5.6 Terra is a closed model whose supported access paths are controlled by its provider.
Next step
Choosing between them
The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.
- Input price: GLM 5.3 Flash costs $0.15 per 1M tokens versus $2 for GPT-5.6 Terra — a 13.3x difference at the headline tier.
- Context: GPT-5.6 Terra takes 1.05M against 1.05M for GLM 5.3 Flash — only decisive if your prompts approach the smaller window.
- Measured capability: GLM 5.3 Flash leads Artificial Analysis Intelligence Index 57 to 50 (measured 2026-08-26).
- Deployment: GLM 5.3 Flash publishes weights you can self-host; the other is API-only.
Choosing a harness rather than a model — Cursor, Copilot, Claude Code, Windsurf, or Lovable? Compare agentic harnesses · Latest releases.