GPT-5.3-Codex vs Kimi K2.7 Code

GPT-5.3-Codex leads Kimi K2.7 Code on coding, 60.0 to 53.4 on the Vibe Coding Index, and Kimi K2.7 Code costs 3.5x less per output token ($4.00 vs $14.00 per million). Updated October 21, 2026; 31 benchmarks have a result for both.

Replace GPT-5.3-Codex Replace Kimi K2.7 Code

GPT-5.3-CodexOpenAI

Coding: 60.0
Overall: No data
Output $/M: $14.00

Kimi K2.7 CodeMoonshot AI

Coding: 53.4
Overall: 56.7
Output $/M: $4.00

vs boards won of 31 shared

GPT-5.3-Codex or Kimi K2.7 Code: which to pick

Pick GPT-5.3-Codex for coding: it scores 60.0 on the Vibe Coding Index against 53.4 for Kimi K2.7 Code, though on 3 benchmarks against 4.

Pick Kimi K2.7 Code for output tokens 3.5x cheaper ($4.00 vs $14.00 per million) and a lower cost per solved task ($0.35 against $0.59).

Model AGPT-5.3-CodexOpenAI60.0/1003 independent benchmarks$0.59 per solved task Model BKimi K2.7 CodeMoonshot AI53.4/1004 independent benchmarks$0.35 per solved task

31320

Shared results: 31
GPT-5.3-Codex only: 3
Kimi K2.7 Code only: 20
Like-for-like categories: 6 of 9

Only benchmarks that tested both models count toward a pick; a result only one model has is shown but not compared.

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
GPT-5.3-Codex
GPT-5.3-Codex scores 60.0 against 53.4.
3 and 4 benchmarks behind the scores
Intelligence
AA Intelligence Index
GPT-5.3-Codex
GPT-5.3-Codex leads, 32.5 against 25.8.
Same board, both measured
Agentic work
AA Agentic Index
No call
Only Kimi K2.7 Code has a AA Agentic Index result, 21.0.
Directional only
Web design
Design Arena: websites
Kimi K2.7 Code
Kimi K2.7 Code leads, 1264 against 1163.
Same board, both measured
Long documents
Listed context window
GPT-5.3-Codex
GPT-5.3-Codex takes 400K tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Kimi K2.7 Code
GPT-5.3-Codex $0.0088, Kimi K2.7 Code $0.0029 per turn.
List prices
Cost per solved task
One SWE-bench Verified task, solved
Kimi K2.7 Code
GPT-5.3-Codex $0.59, Kimi K2.7 Code $0.35.
Published attempt cost and pass rate

At a glance

Coding index: GPT-5.3-Codex 60.0 from 3 benchmarks, Kimi K2.7 Code 53.4 from 4 benchmarks.
Widest category: Web design, 12.1 points apart on average over 8 shared benchmarks.
Widest single gap: Design Arena: 3D: GPT-5.3-Codex 1008 against Kimi K2.7 Code 1241, 29.1 points apart on a 0 to 100 scale.
Output price: GPT-5.3-Codex $14.00 against Kimi K2.7 Code $4.00 per million output tokens, 3.5x apart.
Context window: GPT-5.3-Codex takes 400K tokens, Kimi K2.7 Code 262K.

Benchmark by benchmark

First the score: boards each model leads, per category, where both have a result. Then every board, a category to a fold; bars are each result on a 0 to 100 scale, so compare the two in a row, not one row with another.

Boards won, where both have a result
Category	GPT-5.3-Codex	Kimi K2.7 Code
Coding	5	5
Intelligence	2	0
Agentic work	1	6
Reasoning	2	0
Web design	0	8
General	2	0
All shared boards	12	19

CodingLike-for-likeSix of these boards feed the Vibe Coding Index55

Coding benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
LMArena WebDev	1407	1474	Kimi K2.7 Code
AA Coding Index	Not measured	60.8	Only Kimi K2.7 Code measured
LiveCodeBench (Vals AI)	87.3%	82.0%	GPT-5.3-Codex
SWE-bench Verified (Vals AI)	78.0%	78.2%	Kimi K2.7 Code
Vibe Code Bench (Vals AI)	61.8%	47.2%	GPT-5.3-Codex
Code migration (Vals AI)	Not measured	25.4%	Only Kimi K2.7 Code measured
ProgramBench (Vals AI)	Not measured	0.0%	Only Kimi K2.7 Code measured
IOI (Vals AI)	53.8%	Not measured	Only GPT-5.3-Codex measured
Terminal-Bench 2.1 (Vals AI)	Not measured	67.0%	Only Kimi K2.7 Code measured
SkillsBench (Vals AI)	Not measured	50.0%	Only Kimi K2.7 Code measured
SciCode	Not measured	47.8%	Only Kimi K2.7 Code measured
Terminal-Bench Hard (Artificial Analysis run)	53.0%	44.7%	GPT-5.3-Codex
Terminal-Bench	78.4%	Not measured	Only GPT-5.3-Codex measured
FrontierCode	Not measured	30.1%	Only Kimi K2.7 Code measured
WeirdML	79.3%	54.1%	GPT-5.3-Codex
ALE-Bench	1655.2	886.2	GPT-5.3-Codex
LMArena WebDev: React	1395	1475	Kimi K2.7 Code
LMArena WebDev: HTML	1422	1451	Kimi K2.7 Code
LMArena WebDev: from an image	1443	1513	Kimi K2.7 Code
Neither model has a result on the other 20 boards here

IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20

Intelligence benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
AA Intelligence Index	32.5	25.8	GPT-5.3-Codex
Epoch Capabilities Index	157.1	150.1	GPT-5.3-Codex

Agentic workLike-for-likePublic boards, shown as published, kept out of the index16

Agentic work benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
AA Agentic Index	Not measured	21.0	Only Kimi K2.7 Code measured
Design Arena: agents building web apps	1032	1176	Kimi K2.7 Code
Design Arena: agents building full-stack apps	983	1175	Kimi K2.7 Code
Design Arena: agents building mobile apps	1054	1143	Kimi K2.7 Code
Design Arena: agents building Android apps	1084	1137	Kimi K2.7 Code
Design Arena: agents building Godot games	1124	1147	Kimi K2.7 Code
Design Arena: agents building games	Not measured	1131	Only Kimi K2.7 Code measured
Design Arena: HTML slides	Not measured	1201	Only Kimi K2.7 Code measured
Design Arena: PowerPoint slides	Not measured	1154	Only Kimi K2.7 Code measured
τ²-Bench Telecom	86.0%	90.1%	Kimi K2.7 Code
APEX-Agents	Not measured	37.6%	Only Kimi K2.7 Code measured
METR time horizons	74.5%	Not measured	Only GPT-5.3-Codex measured
Vending-Bench 2	$5,940	$5,083	GPT-5.3-Codex
Neither model has a result on the other 28 boards here

ReasoningLike-for-likePublic boards, shown as published, kept out of the index20

Reasoning benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
GPQA Diamond (Artificial Analysis run)	91.5%	89.6%	GPT-5.3-Codex
Humanity's Last Exam (Artificial Analysis run)	42.5%	35.0%	GPT-5.3-Codex
GPQA Diamond (Epoch AI run)	Not measured	87.9%	Only Kimi K2.7 Code measured
SimpleBench	Not measured	57.9%	Only Kimi K2.7 Code measured
Chess puzzles	Not measured	14.0%	Only Kimi K2.7 Code measured
Neither model has a result on the other 17 boards here

MathDirectional onlyPublic boards, shown as published, kept out of the index3 boards, none shared

Math benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
OTIS Mock AIME	Not measured	95.6%	Only Kimi K2.7 Code measured
FrontierMath, tiers 1 to 3	Not measured	54.0%	Only Kimi K2.7 Code measured
FrontierMath, tier 4	Not measured	12.2%	Only Kimi K2.7 Code measured
Neither model has a result on the other 10 boards here

KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index1 board, none shared

Knowledge benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
SimpleQA Verified	Not measured	36.5%	Only Kimi K2.7 Code measured
Neither model has a result on the other 17 boards here

Web designLike-for-likePublic boards, shown as published, kept out of the index08

Web design benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
Design Arena: websites	1163	1264	Kimi K2.7 Code
Design Arena: UI components	1137	1259	Kimi K2.7 Code
Design Arena: game dev	1161	1220	Kimi K2.7 Code
Design Arena: data viz	1164	1227	Kimi K2.7 Code
Design Arena: 3D	1008	1241	Kimi K2.7 Code
Design Arena: all code categories	1145	1253	Kimi K2.7 Code
Design Arena: SVG	1129	1176	Kimi K2.7 Code
Design Arena: ASCII art	1152	1196	Kimi K2.7 Code
Neither model has a result on the other 1 board here

GeneralLike-for-likePublic boards, shown as published, kept out of the index20

General benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
IFBench	75.4%	63.1%	GPT-5.3-Codex
Long context reasoning (AA-LCR)	83.3%	79.3%	GPT-5.3-Codex
Surface Evolver Bench	Not measured	48.8%	Only Kimi K2.7 Code measured
Neither model has a result on the other 43 boards here

Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared

Image generation benchmarks for GPT-5.3-Codex and Kimi K2.7 Code
Benchmark	GPT-5.3-Codex	Kimi K2.7 Code	Leader
Neither model has a result on 5 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

GPT-5.3-Codex$0.0088Fits in one request

Kimi K2.7 Code$0.0029Fits in one request

Kimi K2.7 Code costs less

Repository review

50K input + 3K output tokens

GPT-5.3-Codex$0.130Fits in one request

Kimi K2.7 Code$0.059Fits in one request

Kimi K2.7 Code costs less

Agent loop

200K input + 10K output tokens

GPT-5.3-Codex$0.490Fits in one request

Kimi K2.7 Code$0.230Fits in one request

Kimi K2.7 Code 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.

Specifications of GPT-5.3-Codex and Kimi K2.7 Code
Specification	OpenAI GPT-5.3-Codex	MoonshotAI Kimi K2.7 Code
Maker	OpenAI	Moonshot AI
Weights	No public weights listed	Open weights
Released	February 24, 2026	June 12, 2026
Context window	400K	262K
Input $/Mtok	$1.75	$0.95
Output $/Mtok	$14.00	$4.00
Coding index	60.0	53.4
Independent measurements behind it	3	4
Cost per solved task	$0.59	$0.35
Source	OpenRouter listing	OpenRouter listing

Questions

Is GPT-5.3-Codex better than Kimi K2.7 Code for coding?

Pick GPT-5.3-Codex for coding: it scores 60.0 on the Vibe Coding Index against 53.4 for Kimi K2.7 Code, though on 3 benchmarks against 4. Pick Kimi K2.7 Code for output tokens 3.5x cheaper ($4.00 vs $14.00 per million) and a lower cost per solved task ($0.35 against $0.59).

Which is cheaper, GPT-5.3-Codex or Kimi K2.7 Code?

GPT-5.3-Codex costs $1.75 per million input tokens and $14.00 per million output tokens; Kimi K2.7 Code costs $0.95 and $4.00. Per solved SWE-bench Verified task, GPT-5.3-Codex costs $0.59 and Kimi K2.7 Code $0.35.

Which has the bigger context window, GPT-5.3-Codex or Kimi K2.7 Code?

GPT-5.3-Codex, with 400K tokens against 262K.

How many benchmarks is the GPT-5.3-Codex vs Kimi K2.7 Code comparison based on?

31 benchmarks have a result for both models as of October 21, 2026. GPT-5.3-Codex's coding index rests on 3 independent benchmarks and Kimi K2.7 Code's on 4. Where only one model has a result, the page says so instead of naming a winner.

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GPT-5.3-Codex or Kimi K2.7 Code: which to pick

Which one for your work

Coding

Intelligence

Agentic work

Web design

Long documents

Everyday cost

Cost per solved task

At a glance

Benchmark by benchmark

What each workload costs

Chat turn

Repository review

Agent loop

Specification differences

Questions

Compare next