# GPT-5.3 Codex vs Beam

> Side-by-side benchmark comparison for GPT-5.3 Codex and Beam across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-3-codex-vs-reflection-beam
- Last updated: October 5, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: GPT-5.3 Codex and Beam share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Beam has the lower published output-token price.
- GPT-5.3 Codex has the larger published context window at 400K.

## Model Snapshot

| Property | GPT-5.3 Codex | Beam |
|----------|----------|----------|
| Creator | OpenAI | Reflection AI |
| Type | Proprietary | Pending |
| Reasoning | Reasoning | Reasoning |
| Context | 400K | null |
| Independent public score (not head-to-head) | 60.79 | null |
| Benchmarks Covered | 10 | 16 |
| Pricing (input/output) | $1.75 / $14.00 | Pricing unavailable / Pricing unavailable |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 54.9 (Estimated · #35/119)
- Beam public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Beam | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 77.3% | Coming soon | Coming soon |
| OSWorld-Verified | 64.7% | Coming soon | Coming soon |
| Gert Labs | 57.47% | Coming soon | Coming soon |
| JobBench | 33.7% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 80.1% | Coming soon |
| MCP Atlas | Coming soon | 78.7% | Coming soon |
| BrowseComp | Coming soon | 77.4% | Coming soon |
| DeepSearchQA | Coming soon | 80.1% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 55.6 (Supported · #28/144)
- Beam public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Beam | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85% | 80.9% | GPT-5.3 Codex |
| SWE-bench Pro | 56.8% | 65.5% | Beam |
| SWE-Rebench | 58.2% | Coming soon | Coming soon |
| Vibe Code Bench | 61.77% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 87.3% | Coming soon | Coming soon |
| SWE-bench (Vals) | 78.0% | Coming soon | Coming soon |
| DeepSWE | Coming soon | 44.4% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 80.1% | Coming soon |
| SWE-Atlas Codebase QnA | Coming soon | 34.6% | Coming soon |
| SWE Multilingual | Coming soon | 78% | Coming soon |
| SciCode | Coming soon | 49.7% | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 79.6 (Unranked · 2 rankable rows)
- Beam public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Beam | Winner |
|-----------|-----------|-----------|--------|
| LongBench v2 | Coming soon | 65.5% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 76.7 (Unranked · 1 rankable row)
- Beam public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 64.4 (Estimated · #27/171)
- Beam public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Beam | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | Coming soon | 90.5% | Coming soon |
| HLE w/o tools | Coming soon | 36.2% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: 91.2 (#14/125)
- Beam public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Beam | Winner |
|-----------|-----------|-----------|--------|
| IFBench | Coming soon | 79.7% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- GPT-5.3 Codex public-lane score: Coming soon
- Beam public-lane score: Coming soon

| Benchmark | GPT-5.3 Codex | Beam | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | Coming soon | 97.8% | Coming soon |

## FAQ

### Is there enough evidence to pick between GPT-5.3 Codex and Beam?

Not yet. The models share only 2 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [GPT-5.3 Codex vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-vs-gpt-5-3-codex-spark)
- [Beam vs GPT-5.3-Codex-Spark](/compare/gpt-5-3-codex-spark-vs-reflection-beam)
- [GPT-5.3 Codex vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gpt-5-3-codex)
- [Beam vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-reflection-beam)

## Explore More

- [GPT-5.3 Codex profile](/models/gpt-5-3-codex)
- [Beam profile](/models/reflection-beam)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)