Data points: 67
The readout for GPT-5.3 Codex and Grok-3, before the detailed comparison sheet.
Decision read
GPT-5.3 Codex
GPT-5.3 Codex currently has the stronger profile, with verified wins split 4 to 1.
Evidence depth
67 data points
Includes 6 benchmark rows, 0 audit samples, and 8 provider examples.
Selection signal
Start with GPT-5.3 Codex
The charts below split 14 high-signal samples across speed, scores, and audit health.
Model compare GPT-5.3 Codex vs Grok-3gpt-5-3-codex-vs-grok-3 | Model A GPT-5.3 Codex | Model B Grok-3 |
|---|---|---|
| Overall leader | Leading | Contender |
| Verified metric wins | 4 wins | 1 wins |
| Where it leads | Cheapest input price, Average speed, Provider coverage, Recent tests |
Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.
| Metric | GPT-5.3 Codex | Grok-3 |
|---|---|---|
| GPQA | 91.5%#4 |
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | GPT-5.3 Codex | Grok-3 |
|---|---|---|
| No completed audits are available from shared providers yet. | ||
Speed aggregates and input/output pricing share each provider row for real API selection and migration cost checks.
| Provider | GPT-5.3 Codex | Grok-3 |
|---|---|---|
35 tests | GPT-5.3 Codex speed / latency 38 tok/s / 4553ms input / output No data |
This report only uses LMSpeed data for GPT-5.3 Codex and Grok-3: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Guidance | GPT-5.3 Codex | Grok-3 |
|---|---|---|
| When to choose each model | GPT-5.3 Codex GPT-5.3 Codex is stronger when you prioritize Cheapest input price, Average speed, Provider coverage, Recent tests. | Grok-3 Grok-3 is stronger when you prioritize First-token latency. |
TL;DR: GPT-5.3 Codex leads across 67 verifiable data points, including pricing, speed, latency, benchmarks, and provider examples.
Continue from GPT-5.3 Codex vs Grok-3 into nearby model comparisons with enough verified LMSpeed data.
| First-token latency |
| Model metadata | GPT-5.3 Codex exposes 400K tokens; notable signals: Text input, Image input, File input, Text output. | No OpenRouter metadata is available yet for this model. |
|---|---|---|
| Developer | OpenAI | No data |
| Context window | 400K tokens | No data |
| Max output | 128K tokens | No data |
| Released | Feb 2026 | No data |
| Modalities | Input TextImageFile Output Text | No data |
| Features | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning | None listed |
| Parameters | No data | No data |
| Tokenizer | GPT | No data |
| Knowledge cutoff | No data | No data |
| OpenRouter ID | openai/gpt-5.3-codex | No data |
| References | No data | No data |
| HLE | 39.9%#5 | 5.1%#86 |
|---|
| SciCode | 53.2%#8 | 36.8%#67 |
|---|
| Input price | $1.75/M#35 | $4.00/M#40 |
|---|
| Output price | $14.00/M#43 | $20.00/M#46 |
|---|
| Blended price | $4.81/M#62 | $8.00/M#67 |
|---|
Grok-3
speed / latency
N/A / N/A
input / output
No data
DuckCoding5 tests | GPT-5.3 Codex speed / latency 21 tok/s / 2445ms input / output No data | Grok-3 speed / latency N/A / N/A input / output No data |
|---|
Seamee API5 tests | GPT-5.3 Codex speed / latency 53 tok/s / 3889ms input / output No data | Grok-3 speed / latency N/A / N/A input / output No data |
|---|
Undy API5 tests | GPT-5.3 Codex speed / latency N/A / N/A input / output No data | Grok-3 speed / latency 19 tok/s / 4518ms input / output No data |
|---|
0CHAT0 tests | GPT-5.3 Codex speed / latency N/A / N/A input / output No data | Grok-3 speed / latency N/A / N/A input / output No data |
|---|
GPT-5.3 Codex gpt-5.3-codex-openai-compact speed / latency No data input / output $75.00/M / $600.00/M | Grok-3 grok-3 speed / latency No data input / output $0/M / $0/M |
GPT-5.3 Codex gpt-5.3-codex-spark speed / latency No data input / output $0.216/M / $1.73/M | Grok-3 grok-3 speed / latency No data input / output $0.0014/M / $0.0014/M |
GPT-5.3 Codex gpt-5.3-codex speed / latency No data input / output $0.010/M / $0.010/M | Grok-3 grok-3-fast speed / latency No data input / output $0.140/M / $0.140/M |
Rankings are based on community-submitted tests and periodic health probes. Advisory only, not official data.
