GLM 5.3 FlashX vs Grok 4.3
Updated October 21, 2026. No benchmark has tested both models yet. Coding is ranked on the Vibe Coding Index; every other board is shown as published.
- Coding
- No data
- Overall
- No data
- Output $/M
- $1.25
- Coding
- 37.4
- Overall
- 24.9
- Output $/M
- $2.50
Decision reading
Only Grok 4.3 has a coding score, 37.4 on the Vibe Coding Index; GLM 5.3 FlashX has none, so the two cannot be ranked on coding.
GLM 5.3 FlashX has the edge where output tokens cost 2.0x less, and where the context window is larger, 1.05M against 1M tokens.
No benchmark has tested both yet. GLM 5.3 FlashX has none yet; Grok 4.3 on LMArena WebDev, AA Coding Index and LiveCodeBench (Vals AI). Compare them on price and context instead.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Only Grok 4.3 has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
No call
Only Grok 4.3 has a AA Intelligence Index result, 24.9.
Directional only
Agentic work
AA Agentic Index
No call
Only Grok 4.3 has a AA Agentic Index result, 15.5.
Directional only
Reasoning
GPQA Diamond
No call
Only Grok 4.3 has a GPQA Diamond result, 91.4%.
Directional only
Knowledge
MMLU Pro
No call
Only Grok 4.3 has a MMLU Pro result, 85.8%.
Directional only
Web design
Design Arena: websites
No call
Only Grok 4.3 has a Design Arena: websites result, 1196.
Directional only
Long documents
Listed context window
GLM 5.3 FlashX
GLM 5.3 FlashX takes 1.05M tokens against 1M.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GLM 5.3 FlashX
GLM 5.3 FlashX $0.0010, Grok 4.3 $0.0025 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
No call
Only Grok 4.3 has the number, $0.31.
Directional only
At a glance
- Coding index
- GLM 5.3 FlashX not benchmarked, Grok 4.3 37.4 from 3 benchmarks.
- Widest category
- None yet: no category has been tested on both models.
- Widest single gap
- None yet: no benchmark has tested both models.
- Output price
- GLM 5.3 FlashX $1.25 against Grok 4.3 $2.50 per million output tokens, 2.0x apart.
- Context window
- GLM 5.3 FlashX takes 1.05M tokens, Grok 4.3 1M.
Benchmark by benchmark
Every board either model has a result on, a category to a fold; bars are each result on a 0 to 100 scale. Only one model is measured on each, so no row names a leader.
CodingDirectional onlySix of these boards feed the Vibe Coding Index18 boards measured
| Benchmark | GLM 5.3 FlashX | Grok 4.3 | Leader |
|---|---|---|---|
| LMArena WebDev | Not measured | 1358 | Only Grok 4.3 measured |
| AA Coding Index | Not measured | 42.2 | Only Grok 4.3 measured |
| LiveCodeBench (Vals AI) | Not measured | 84.5% | Only Grok 4.3 measured |
| SWE-bench Verified (Vals AI) | Not measured | 71.4% | Only Grok 4.3 measured |
| Vibe Code Bench (Vals AI) | Not measured | 19.4% | Only Grok 4.3 measured |
| Code migration (Vals AI) | Not measured | 6.8% | Only Grok 4.3 measured |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only Grok 4.3 measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 42.0% | Only Grok 4.3 measured |
| SkillsBench (Vals AI) | Not measured | 40.6% | Only Grok 4.3 measured |
| SciCode | Not measured | 48.3% | Only Grok 4.3 measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 37.9% | Only Grok 4.3 measured |
| WeirdML | Not measured | 49.9% | Only Grok 4.3 measured |
| ALE-Bench | Not measured | 944.2 | Only Grok 4.3 measured |
| LMArena Text: coding | Not measured | 1415 | Only Grok 4.3 measured |
| LMArena Text: software and IT | Not measured | 1416 | Only Grok 4.3 measured |
| LMArena WebDev: React | Not measured | 1353 | Only Grok 4.3 measured |
| LMArena WebDev: HTML | Not measured | 1367 | Only Grok 4.3 measured |
| LMArena WebDev: from an image | Not measured | 1375 | Only Grok 4.3 measured |
| Neither model has a result on the other 20 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | GLM 5.3 FlashX | Grok 4.3 | Leader |
|---|---|---|---|
| AA Intelligence Index | Not measured | 24.9 | Only Grok 4.3 measured |
| Neither model has a result on the other 1 board here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index16 boards measured
| Benchmark | GLM 5.3 FlashX | Grok 4.3 | Leader |
|---|---|---|---|
| AA Agentic Index | Not measured | 15.5 | Only Grok 4.3 measured |
| Design Arena: agents building web apps | Not measured | 1126 | Only Grok 4.3 measured |
| Design Arena: agents building full-stack apps | Not measured | 1006 | Only Grok 4.3 measured |
| Design Arena: agents building mobile apps | Not measured | 1059 | Only Grok 4.3 measured |
| Design Arena: agents building Android apps | Not measured | 968 | Only Grok 4.3 measured |
| Design Arena: agents building Godot games | Not measured | 914 | Only Grok 4.3 measured |
| Design Arena: agents building games | Not measured | 1007 | Only Grok 4.3 measured |
| Design Arena: HTML slides | Not measured | 1008 | Only Grok 4.3 measured |
| Design Arena: PowerPoint slides | Not measured | 1013 | Only Grok 4.3 measured |
| Finance Agent (Vals AI) | Not measured | 37.7% | Only Grok 4.3 measured |
| Tax Agent Bench (Vals AI) | Not measured | 6.2% | Only Grok 4.3 measured |
| Legal Research Bench (Vals AI) | Not measured | 15.4% | Only Grok 4.3 measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 18.4% | Only Grok 4.3 measured |
| τ²-Bench Telecom | Not measured | 97.7% | Only Grok 4.3 measured |
| Vending-Bench 2 | Not measured | $35 | Only Grok 4.3 measured |
| LMArena Search | Not measured | 1166 | Only Grok 4.3 measured |
| Neither model has a result on the other 23 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index11 boards measured
| Benchmark | GLM 5.3 FlashX | Grok 4.3 | Leader |
|---|---|---|---|
| GPQA Diamond | Not measured | 91.4% | Only Grok 4.3 measured |
| MMMU Pro (Vals AI) | Not measured | 83.1% | Only Grok 4.3 measured |
| GPQA Diamond (Artificial Analysis run) | Not measured | 90.1% | Only Grok 4.3 measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 37.2% | Only Grok 4.3 measured |
| GPQA Diamond (Epoch AI run) | Not measured | 88.8% | Only Grok 4.3 measured |
| Chess puzzles | Not measured | 18.0% | Only Grok 4.3 measured |
| LMArena Text: hard prompts | Not measured | 1396 | Only Grok 4.3 measured |
| LMArena Text: expert | Not measured | 1384 | Only Grok 4.3 measured |
| LMArena Text: hard prompts in English | Not measured | 1402 | Only Grok 4.3 measured |
| LMArena Vision: diagrams | Not measured | 1241 | Only Grok 4.3 measured |
| LMArena Vision: homework | Not measured | 1241 | Only Grok 4.3 measured |
| Neither model has a result on the other 10 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index6 boards measured
| Benchmark | GLM 5.3 FlashX | Grok 4.3 | Leader |
|---|---|---|---|
| OTIS Mock AIME | Not measured | 93.3% | Only Grok 4.3 measured |
| FrontierMath, tiers 1 to 3 | Not measured | 42.8% | Only Grok 4.3 measured |
| FrontierMath, tier 4 | Not measured | 14.6% | Only Grok 4.3 measured |
| ProofBench | Not measured | 11.0% | Only Grok 4.3 measured |
| LMArena Text: math | Not measured | 1387 | Only Grok 4.3 measured |
| LMArena Text: mathematical work | Not measured | 1396 | Only Grok 4.3 measured |
| Neither model has a result on the other 7 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index12 boards measured
| Benchmark | GLM 5.3 FlashX | Grok 4.3 | Leader |
|---|---|---|---|
| MMLU Pro | Not measured | 85.8% | Only Grok 4.3 measured |
| LegalBench (Vals AI) | Not measured | 84.5% | Only Grok 4.3 measured |
| CaseLaw (Vals AI) | Not measured | 79.3% | Only Grok 4.3 measured |
| CorpFin (Vals AI) | Not measured | 68.5% | Only Grok 4.3 measured |
| TaxEval (Vals AI) | Not measured | 70.8% | Only Grok 4.3 measured |
| MortgageTax (Vals AI) | Not measured | 48.3% | Only Grok 4.3 measured |
| MedCode (Vals AI) | Not measured | 38.1% | Only Grok 4.3 measured |
| SimpleQA Verified | Not measured | 33.2% | Only Grok 4.3 measured |
| LMArena Text: science | Not measured | 1399 | Only Grok 4.3 measured |
| LMArena Text: medicine and healthcare | Not measured | 1384 | Only Grok 4.3 measured |
| LMArena Text: legal and government | Not measured | 1386 | Only Grok 4.3 measured |
| LMArena Text: business and finance | Not measured | 1381 | Only Grok 4.3 measured |
| Neither model has a result on the other 5 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards measured
| Benchmark | GLM 5.3 FlashX | Grok 4.3 | Leader |
|---|---|---|---|
| Design Arena: websites | Not measured | 1196 | Only Grok 4.3 measured |
| Design Arena: UI components | Not measured | 1192 | Only Grok 4.3 measured |
| Design Arena: game dev | Not measured | 1174 | Only Grok 4.3 measured |
| Design Arena: data viz | Not measured | 1180 | Only Grok 4.3 measured |
| Design Arena: 3D | Not measured | 1125 | Only Grok 4.3 measured |
| Design Arena: all code categories | Not measured | 1187 | Only Grok 4.3 measured |
| Design Arena: SVG | Not measured | 1082 | Only Grok 4.3 measured |
| Design Arena: ASCII art | Not measured | 1125 | Only Grok 4.3 measured |
| Neither model has a result on the other 1 board here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index32 boards measured
| Benchmark | GLM 5.3 FlashX | Grok 4.3 | Leader |
|---|---|---|---|
| Public Benefits Bench (Vals AI) | Not measured | 51.7% | Only Grok 4.3 measured |
| SAGE (Vals AI) | Not measured | 19.7% | Only Grok 4.3 measured |
| MedScribe (Vals AI) | Not measured | 74.4% | Only Grok 4.3 measured |
| Vals Multimodal Index | Not measured | 43.3% | Only Grok 4.3 measured |
| IFBench | Not measured | 83.3% | Only Grok 4.3 measured |
| Long context reasoning (AA-LCR) | Not measured | 75.0% | Only Grok 4.3 measured |
| DTBench | Not measured | 90.7% | Only Grok 4.3 measured |
| LMCA | Not measured | 38.3% | Only Grok 4.3 measured |
| LMArena Text | Not measured | 1397 | Only Grok 4.3 measured |
| LMArena Text: instruction following | Not measured | 1366 | Only Grok 4.3 measured |
| LMArena Text: creative writing | Not measured | 1380 | Only Grok 4.3 measured |
| LMArena Vision | Not measured | 1229 | Only Grok 4.3 measured |
| LMArena Text: English | Not measured | 1404 | Only Grok 4.3 measured |
| LMArena Text: non-English | Not measured | 1385 | Only Grok 4.3 measured |
| LMArena Text: Chinese | Not measured | 1422 | Only Grok 4.3 measured |
| LMArena Text: German | Not measured | 1395 | Only Grok 4.3 measured |
| LMArena Text: Japanese | Not measured | 1379 | Only Grok 4.3 measured |
| LMArena Text: Korean | Not measured | 1354 | Only Grok 4.3 measured |
| LMArena Text: French | Not measured | 1411 | Only Grok 4.3 measured |
| LMArena Text: Spanish | Not measured | 1399 | Only Grok 4.3 measured |
| LMArena Text: Russian | Not measured | 1399 | Only Grok 4.3 measured |
| LMArena Text: Polish | Not measured | 1398 | Only Grok 4.3 measured |
| LMArena Text: multi-turn | Not measured | 1406 | Only Grok 4.3 measured |
| LMArena Text: longer queries | Not measured | 1393 | Only Grok 4.3 measured |
| LMArena Text: writing and language | Not measured | 1385 | Only Grok 4.3 measured |
| LMArena Text: entertainment and media | Not measured | 1370 | Only Grok 4.3 measured |
| LMArena Vision: English | Not measured | 1235 | Only Grok 4.3 measured |
| LMArena Vision: Chinese | Not measured | 1257 | Only Grok 4.3 measured |
| LMArena Vision: reading text | Not measured | 1235 | Only Grok 4.3 measured |
| LMArena Vision: humor | Not measured | 1222 | Only Grok 4.3 measured |
| LMArena Vision: recognizing things | Not measured | 1217 | Only Grok 4.3 measured |
| LMArena Vision: creative writing | Not measured | 1237 | Only Grok 4.3 measured |
| Neither model has a result on the other 14 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
GLM 5.3 FlashX costs less
Repository review
50K input + 3K output tokens
GLM 5.3 FlashX costs less
Agent loop
200K input + 10K output tokens
GLM 5.3 FlashX costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | Z.ai GLM 5.3 FlashX | SpaceXAI Grok 4.3 |
|---|---|---|
| Maker | Z.ai | xAI |
| Weights | No public weights listed | No public weights listed |
| Released | September 18, 2026 | April 30, 2026 |
| Context window | 1.05M | 1M |
| Input $/Mtok | $0.37 | $1.25 |
| Output $/Mtok | $1.25 | $2.50 |
| Coding index | Not benchmarked | 37.4 |
| Independent measurements behind it | 0 | 3 |
| Cost per solved task | Not computable | $0.31 |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GLM 5.3 FlashX better than Grok 4.3 for coding?
Only Grok 4.3 has a coding score, 37.4 on the Vibe Coding Index; GLM 5.3 FlashX has none, so the two cannot be ranked on coding. GLM 5.3 FlashX has the edge where output tokens cost 2.0x less, and where the context window is larger, 1.05M against 1M tokens.
Which is cheaper, GLM 5.3 FlashX or Grok 4.3?
GLM 5.3 FlashX costs $0.37 per million input tokens and $1.25 per million output tokens; Grok 4.3 costs $1.25 and $2.50. Cost per solved task is known for Grok 4.3 only.
Which has the bigger context window, GLM 5.3 FlashX or Grok 4.3?
GLM 5.3 FlashX, with 1.05M tokens against 1M.
Has any benchmark tested both GLM 5.3 FlashX and Grok 4.3?
No benchmark has tested both yet. GLM 5.3 FlashX has none yet; Grok 4.3 on LMArena WebDev, AA Coding Index and LiveCodeBench (Vals AI). Compare them on price and context instead. Data as of October 21, 2026.