GLM 5.3 FlashX vs GPT-4o
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
- No data
- Overall
- No data
- Output $/M
- $10.00
Decision reading
Neither model has a coding score yet, so the two cannot be ranked on coding.
GLM 5.3 FlashX has the edge where output tokens cost 8.0x less, and where the context window is larger, 1.05M against 128K tokens.
No benchmark has tested both yet. GLM 5.3 FlashX has none yet; GPT-4o on SWE-bench Verified, SWE-bench Lite and SWE-bench (full test set). 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
Neither has a coding score yet.
One side not measured
Web design
Design Arena: websites
No call
Only GPT-4o has a Design Arena: websites result, 831.
Directional only
Long documents
Listed context window
GLM 5.3 FlashX
GLM 5.3 FlashX takes 1.05M tokens against 128K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
GLM 5.3 FlashX
GLM 5.3 FlashX $0.0010, GPT-4o $0.0075 per turn.
List prices
At a glance
- Coding index
- GLM 5.3 FlashX not benchmarked, GPT-4o not benchmarked.
- 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 GPT-4o $10.00 per million output tokens, 8.0x apart.
- Context window
- GLM 5.3 FlashX takes 1.05M tokens, GPT-4o 128K.
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 Index6 boards measured
| Benchmark | GLM 5.3 FlashX | GPT-4o | Leader |
|---|---|---|---|
| SWE-bench Verified | Not measured | 38.8% | Only GPT-4o measured |
| SWE-bench Lite | Not measured | 38.0% | Only GPT-4o measured |
| SWE-bench (full test set) | Not measured | 18.8% | Only GPT-4o measured |
| SWE-bench Multimodal | Not measured | 30.4% | Only GPT-4o measured |
| LiveCodeBench (Artificial Analysis run) | Not measured | 30.9% | Only GPT-4o measured |
| Terminal-Bench Hard (Artificial Analysis run) | Not measured | 8.3% | Only GPT-4o measured |
| Neither model has a result on the other 32 boards here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | GLM 5.3 FlashX | GPT-4o | Leader |
|---|---|---|---|
| τ²-Bench Telecom | Not measured | 25.1% | Only GPT-4o measured |
| GDPval | Not measured | 9.9% | Only GPT-4o measured |
| Neither model has a result on the other 37 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index4 boards measured
| Benchmark | GLM 5.3 FlashX | GPT-4o | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | Not measured | 54.3% | Only GPT-4o measured |
| Humanity's Last Exam (Artificial Analysis run) | Not measured | 2.4% | Only GPT-4o measured |
| ARC-AGI | Not measured | 4.5% | Only GPT-4o measured |
| ARC-AGI-2 | Not measured | 0.0% | Only GPT-4o measured |
| Neither model has a result on the other 17 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | GLM 5.3 FlashX | GPT-4o | Leader |
|---|---|---|---|
| AA Math Index | Not measured | 6.0 | Only GPT-4o measured |
| AIME 2025 (Artificial Analysis run) | Not measured | 6.0% | Only GPT-4o measured |
| Neither model has a result on the other 11 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | GLM 5.3 FlashX | GPT-4o | Leader |
|---|---|---|---|
| MMLU Pro (Artificial Analysis run) | Not measured | 74.8% | Only GPT-4o measured |
| MMLU | Not measured | 88.1% | Only GPT-4o measured |
| Neither model has a result on the other 15 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index6 boards measured
| Benchmark | GLM 5.3 FlashX | GPT-4o | Leader |
|---|---|---|---|
| Design Arena: websites | Not measured | 831 | Only GPT-4o measured |
| Design Arena: UI components | Not measured | 885 | Only GPT-4o measured |
| Design Arena: game dev | Not measured | 906 | Only GPT-4o measured |
| Design Arena: data viz | Not measured | 858 | Only GPT-4o measured |
| Design Arena: 3D | Not measured | 869 | Only GPT-4o measured |
| Design Arena: all code categories | Not measured | 861 | Only GPT-4o measured |
| Neither model has a result on the other 3 boards here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index4 boards measured
| Benchmark | GLM 5.3 FlashX | GPT-4o | Leader |
|---|---|---|---|
| IFBench | Not measured | 34.3% | Only GPT-4o measured |
| Long context reasoning (AA-LCR) | Not measured | 49.3% | Only GPT-4o measured |
| DTBench | Not measured | 64.5% | Only GPT-4o measured |
| LMCA | Not measured | 16.6% | Only GPT-4o measured |
| Neither model has a result on the other 42 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 | OpenAI GPT-4o |
|---|---|---|
| Maker | Z.ai | OpenAI |
| Weights | No public weights listed | No public weights listed |
| Released | September 18, 2026 | May 13, 2024 |
| Context window | 1.05M | 128K |
| Input $/Mtok | $0.37 | $2.50 |
| Output $/Mtok | $1.25 | $10.00 |
| Coding index | Not benchmarked | Not benchmarked |
| Independent measurements behind it | 0 | 0 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is GLM 5.3 FlashX better than GPT-4o for coding?
Neither model has a coding score yet, so the two cannot be ranked on coding. GLM 5.3 FlashX has the edge where output tokens cost 8.0x less, and where the context window is larger, 1.05M against 128K tokens.
Which is cheaper, GLM 5.3 FlashX or GPT-4o?
GLM 5.3 FlashX costs $0.37 per million input tokens and $1.25 per million output tokens; GPT-4o costs $2.50 and $10.00. Cost per solved task is known for neither of them.
Which has the bigger context window, GLM 5.3 FlashX or GPT-4o?
GLM 5.3 FlashX, with 1.05M tokens against 128K.
Has any benchmark tested both GLM 5.3 FlashX and GPT-4o?
No benchmark has tested both yet. GLM 5.3 FlashX has none yet; GPT-4o on SWE-bench Verified, SWE-bench Lite and SWE-bench (full test set). Compare them on price and context instead. Data as of October 21, 2026.