Data points: 64
The readout for GPT-5.3 Codex and Seed 1.6 Flash, before the detailed comparison sheet.
Decision read
GPT-5.3 Codex
GPT-5.3 Codex currently has the stronger profile, with verified wins split 3 to 1.
Evidence depth
64 data points
Includes 1 benchmark rows, 0 audit samples, and 5 provider examples.
Selection signal
Start with GPT-5.3 Codex
The charts below split 6 high-signal samples across speed, scores, and audit health.
Switch either side of this report to compare another model with the same LMSpeed data pipeline.
Select a different model to open a new comparison URL.
Model compare GPT-5.3 Codex vs Seed 1.6 Flashgpt-5-3-codex-vs-seed-1-6-flash | Model A GPT-5.3 Codex | Model B Seed 1.6 Flash |
|---|---|---|
| Overall leader | Leading | Contender |
| Verified metric wins | 3 wins | 1 wins |
| Where it leads | Free providers, Provider coverage, Recent tests | Cheapest input price |
Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.
Compare benchmark category scores on a 0-100 scale. Select a category to inspect the gap.
Avg. score
GPT-5.3 Codex
58.2
Avg. score
Seed 1.6 Flash
-
Selected category
Agents
GPT-5.3 Codex
Metric-level scores with benchmark source, rank depth, confidence, error, and evaluation date where available.
GPT-5.3 Codex
winner82.0
Rank #11/127 · confidence 1 · eval date 2026-02-05
Seed 1.6 Flash
4.0
Rank #125/127 · confidence 1 · eval date 2025-06-01
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | GPT-5.3 Codex | Seed 1.6 Flash |
|---|---|---|
| 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 | Seed 1.6 Flash |
|---|---|---|
0 tests | GPT-5.3 Codex speed / latency N/A / N/A input / output No data | Seed 1.6 Flash |
This report only uses LMSpeed data for GPT-5.3 Codex and Seed 1.6 Flash: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Guidance | GPT-5.3 Codex | Seed 1.6 Flash |
|---|---|---|
| When to choose each model | GPT-5.3 Codex GPT-5.3 Codex is stronger when you prioritize Free providers, Provider coverage, Recent tests. | Seed 1.6 Flash Seed 1.6 Flash is stronger when you prioritize Cheapest input price. |
TL;DR: GPT-5.3 Codex leads across 64 verifiable data points, including pricing, speed, latency, benchmarks, and provider examples.
Continue from GPT-5.3 Codex vs Seed 1.6 Flash into nearby model comparisons with enough verified LMSpeed data.
| Model metadata | GPT-5.3 Codex exposes 400K tokens; notable signals: Text input, Image input, File input, Text output. | Seed 1.6 Flash exposes 262.1K tokens; notable signals: Text input, Image input, Text output, Tool calling. |
|---|---|---|
| Developer | OpenAI | ByteDance Seed |
| Context window | 400K tokens | 262.1K tokens |
| Max output | 128K tokens | 32.8K tokens |
| Released | Feb 2026 | Dec 2025 |
| Modalities | Input TextImageFile Output Text | Input ImageTextvideo Output Text |
| Features | Text inputImage inputFile inputText outputTool callingStructured outputsJSON modeReasoning | Text inputImage inputText outputTool callingStructured outputsJSON modeReasoning |
| Parameters | No data | No data |
| Tokenizer | GPT | Other |
| Knowledge cutoff | No data | No data |
| OpenRouter ID | openai/gpt-5.3-codex | bytedance-seed/seed-1.6-flash |
| References | No data | No data |
speed / latency
N/A / N/A
input / output
No data
AIsa0 tests | GPT-5.3 Codex speed / latency N/A / N/A input / output No data | Seed 1.6 Flash speed / latency N/A / N/A input / output No data |
|---|
Dext API0 tests | GPT-5.3 Codex openai/gpt-5.3-codex speed / latency N/A / N/A input / output $0.144/M/$1.15/M | Seed 1.6 Flash bytedance-seed/seed-1.6-flash speed / latency N/A / N/A input / output $0.0062/M/$0.025/M |
|---|
OpenRouter0 tests | GPT-5.3 Codex speed / latency N/A / N/A input / output No data | Seed 1.6 Flash speed / latency N/A / N/A input / output No data |
|---|
OpenRouter Fans0 tests | GPT-5.3 Codex speed / latency N/A / N/A input / output No data | Seed 1.6 Flash speed / latency N/A / N/A input / output No data |
|---|
Rankings are based on community-submitted tests and periodic health probes. Advisory only, not official data.
