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DeepSeek V4 Flash 0423 vs gpt-oss-20b

Updated October 21, 2026. 35 benchmarks have a result for both. Coding is ranked on the Vibe Coding Index; every other board is shown as published.

Replace DeepSeek V4 Flash 0423 Replace gpt-oss-20b
DeepSeek V4 Flash 0423DeepSeek
Coding
No data
Overall
24.4
Output $/M
$0.28
35
gpt-oss-20bOpenAI
Coding
No data
Overall
10.0
Output $/M
$0.15
0
vs boards won of 35 shared

Decision reading

Neither model has a coding score yet, so the two cannot be ranked on coding.

DeepSeek V4 Flash 0423 has the edge where the context window is larger, 1.05M against 131K tokens.

Model ADeepSeek V4 Flash 0423DeepSeekNot benchmarked1 independent benchmarkNo cost per solved taskModel Bgpt-oss-20bOpenAINot benchmarkedNo coding benchmarkNo cost per solved task
Shared results
35
DeepSeek V4 Flash 0423 only
13
gpt-oss-20b only
25
Like-for-like categories
7 of 9

Shared results can support a head-to-head reading. Results only one model has describe coverage, not superiority.

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.

At a glance

Coding index
DeepSeek V4 Flash 0423 not benchmarked, gpt-oss-20b not benchmarked.
Widest category
Web design, 34.3 points apart on average over 2 shared benchmarks.
Widest single gap
Design Arena: websites: DeepSeek V4 Flash 0423 1208 against gpt-oss-20b 853, 44.4 points apart on a 0 to 100 scale.
Output price
DeepSeek V4 Flash 0423 $0.28 against gpt-oss-20b $0.15 per million output tokens, 1.9x apart.
Context window
DeepSeek V4 Flash 0423 takes 1.05M tokens, gpt-oss-20b 131K.

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
CategoryDeepSeek V4 Flash 0423Barsgpt-oss-20bTies
Coding40
Intelligence20
Reasoning30
Math20
Knowledge40
Web design20
General180
All shared boards350
CodingLike-for-likeSix of these boards feed the Vibe Coding Index40
Coding benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
LMArena WebDev1582Not measuredOnly DeepSeek V4 Flash 0423 measured
AA Coding Index52.0Not measuredOnly DeepSeek V4 Flash 0423 measured
LiveCodeBench (Vals AI)Not measured80.4%Only gpt-oss-20b measured
LiveCodeBench (Artificial Analysis run)Not measured77.7%Only gpt-oss-20b measured
SciCodeNot measured38.9%Only gpt-oss-20b measured
Terminal-Bench Hard (Artificial Analysis run)Not measured10.6%Only gpt-oss-20b measured
Terminal-BenchNot measured3.4%Only gpt-oss-20b measured
WeirdML45.6%40.9%DeepSeek V4 Flash 0423
ALE-Bench678.2566.0DeepSeek V4 Flash 0423
LMArena Text: coding14571307DeepSeek V4 Flash 0423
LMArena Text: software and IT14531311DeepSeek V4 Flash 0423
LMArena WebDev: React1585Not measuredOnly DeepSeek V4 Flash 0423 measured
LMArena WebDev: HTML1558Not measuredOnly DeepSeek V4 Flash 0423 measured
Neither model has a result on the other 25 boards here
IntelligenceLike-for-likePublic boards, shown as published, kept out of the index20
Intelligence benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
AA Intelligence Index24.410.0DeepSeek V4 Flash 0423
Epoch Capabilities Index146.1137.7DeepSeek V4 Flash 0423
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index2 boards, none shared
Agentic work benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
AA Agentic Index26.3Not measuredOnly DeepSeek V4 Flash 0423 measured
τ²-Bench TelecomNot measured60.2%Only gpt-oss-20b measured
Neither model has a result on the other 37 boards here
ReasoningLike-for-likePublic boards, shown as published, kept out of the index30
Reasoning benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
GPQA DiamondNot measured68.9%Only gpt-oss-20b measured
GPQA Diamond (Artificial Analysis run)Not measured68.8%Only gpt-oss-20b measured
Humanity's Last Exam (Artificial Analysis run)Not measured11.0%Only gpt-oss-20b measured
GPQA Diamond (Epoch AI run)Not measured60.8%Only gpt-oss-20b measured
SimpleBench46.3%Not measuredOnly DeepSeek V4 Flash 0423 measured
LMArena Text: hard prompts14441274DeepSeek V4 Flash 0423
LMArena Text: expert14411258DeepSeek V4 Flash 0423
LMArena Text: hard prompts in English14491292DeepSeek V4 Flash 0423
Neither model has a result on the other 13 boards here
MathLike-for-likePublic boards, shown as published, kept out of the index20
Math benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
AIMENot measured86.0%Only gpt-oss-20b measured
MATH 500 (Vals AI)Not measured94.2%Only gpt-oss-20b measured
MGSM (Vals AI)Not measured89.0%Only gpt-oss-20b measured
AA Math IndexNot measured89.3Only gpt-oss-20b measured
AIME 2025 (Artificial Analysis run)Not measured89.3%Only gpt-oss-20b measured
OTIS Mock AIMENot measured65.3%Only gpt-oss-20b measured
LMArena Text: math14261317DeepSeek V4 Flash 0423
LMArena Text: mathematical work14321305DeepSeek V4 Flash 0423
Neither model has a result on the other 5 boards here
KnowledgeLike-for-likePublic boards, shown as published, kept out of the index40
Knowledge benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
MMLU ProNot measured71.6%Only gpt-oss-20b measured
LegalBench (Vals AI)Not measured70.8%Only gpt-oss-20b measured
CaseLaw (Vals AI)Not measured43.8%Only gpt-oss-20b measured
CorpFin (Vals AI)Not measured53.1%Only gpt-oss-20b measured
TaxEval (Vals AI)Not measured63.7%Only gpt-oss-20b measured
MedQA (Vals AI)Not measured82.9%Only gpt-oss-20b measured
MMLU Pro (Artificial Analysis run)Not measured74.8%Only gpt-oss-20b measured
LMArena Text: science14461296DeepSeek V4 Flash 0423
LMArena Text: medicine and healthcare14481310DeepSeek V4 Flash 0423
LMArena Text: legal and government14391280DeepSeek V4 Flash 0423
LMArena Text: business and finance14251284DeepSeek V4 Flash 0423
Neither model has a result on the other 6 boards here
Web designLike-for-likePublic boards, shown as published, kept out of the index20
Web design benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
Design Arena: websites1208853DeepSeek V4 Flash 0423
Design Arena: UI components1165Not measuredOnly DeepSeek V4 Flash 0423 measured
Design Arena: game dev1197Not measuredOnly DeepSeek V4 Flash 0423 measured
Design Arena: data viz1127933DeepSeek V4 Flash 0423
Design Arena: 3D1189Not measuredOnly DeepSeek V4 Flash 0423 measured
Design Arena: all code categories1205Not measuredOnly DeepSeek V4 Flash 0423 measured
Design Arena: SVG1155Not measuredOnly DeepSeek V4 Flash 0423 measured
Design Arena: ASCII art1109Not measuredOnly DeepSeek V4 Flash 0423 measured
Neither model has a result on the other 1 board here
GeneralLike-for-likePublic boards, shown as published, kept out of the index180
General benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
IFBenchNot measured65.1%Only gpt-oss-20b measured
Long context reasoning (AA-LCR)Not measured34.7%Only gpt-oss-20b measured
DTBench86.4%68.0%DeepSeek V4 Flash 0423
LMCA35.9%14.5%DeepSeek V4 Flash 0423
LMArena Text14321288DeepSeek V4 Flash 0423
LMArena Text: instruction following14211236DeepSeek V4 Flash 0423
LMArena Text: creative writing14031201DeepSeek V4 Flash 0423
LMArena Text: English14411303DeepSeek V4 Flash 0423
LMArena Text: non-English14191269DeepSeek V4 Flash 0423
LMArena Text: Chinese14631315DeepSeek V4 Flash 0423
LMArena Text: German14191255DeepSeek V4 Flash 0423
LMArena Text: Japanese13891244DeepSeek V4 Flash 0423
LMArena Text: Korean13831236DeepSeek V4 Flash 0423
LMArena Text: French1439Not measuredOnly DeepSeek V4 Flash 0423 measured
LMArena Text: Spanish14361267DeepSeek V4 Flash 0423
LMArena Text: Russian14271278DeepSeek V4 Flash 0423
LMArena Text: Polish14361252DeepSeek V4 Flash 0423
LMArena Text: multi-turn14491268DeepSeek V4 Flash 0423
LMArena Text: longer queries14341250DeepSeek V4 Flash 0423
LMArena Text: writing and language14101238DeepSeek V4 Flash 0423
LMArena Text: entertainment and media14001216DeepSeek V4 Flash 0423
Neither model has a result on the other 25 boards here
Image generationNot comparablePublic boards, shown as published, kept out of the index0 boards, none shared
Image generation benchmarks for DeepSeek V4 Flash 0423 and gpt-oss-20b
BenchmarkDeepSeek V4 Flash 0423gpt-oss-20bLeader
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

DeepSeek V4 Flash 0423$0.0003Fits in one request
gpt-oss-20b$0.0001Fits in one request

gpt-oss-20b costs less

Repository review

50K input + 3K output tokens

DeepSeek V4 Flash 0423$0.0078Fits in one request
gpt-oss-20b$0.0019Fits in one request

gpt-oss-20b costs less

Agent loop

200K input + 10K output tokens

DeepSeek V4 Flash 0423$0.031Fits in one request
gpt-oss-20b$0.0075Exceeds the context window

gpt-oss-20b 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 DeepSeek V4 Flash 0423 and gpt-oss-20b
SpecificationDeepSeek V4 Flash 0423OpenAI gpt-oss-20b
MakerDeepSeekOpenAI
WeightsOpen weightsOpen weights
ReleasedApril 24, 2026August 5, 2025
Context window1.05M131K
Input $/Mtok$0.14$0.03
Output $/Mtok$0.28$0.15
Coding indexNot benchmarkedNot benchmarked
Independent measurements behind it10
Cost per solved taskNot computableNot computable
SourceOpenRouter listingOpenRouter listing

Questions

Is DeepSeek V4 Flash 0423 better than gpt-oss-20b for coding?

Neither model has a coding score yet, so the two cannot be ranked on coding. DeepSeek V4 Flash 0423 has the edge where the context window is larger, 1.05M against 131K tokens.

Which is cheaper, DeepSeek V4 Flash 0423 or gpt-oss-20b?

DeepSeek V4 Flash 0423 costs $0.14 per million input tokens and $0.28 per million output tokens; gpt-oss-20b costs $0.03 and $0.15. Cost per solved task is known for neither of them.

Which has the bigger context window, DeepSeek V4 Flash 0423 or gpt-oss-20b?

DeepSeek V4 Flash 0423, with 1.05M tokens against 131K.

How many benchmarks is the DeepSeek V4 Flash 0423 vs gpt-oss-20b comparison based on?

35 benchmarks have a result for both models as of October 21, 2026. DeepSeek V4 Flash 0423's coding index rests on 1 independent benchmark and gpt-oss-20b's on 0. Where only one model has a result, the page says so instead of naming a winner.

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