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AI Desk · AI FingerprintingNew arrival

DeepSeek: DeepSeek V4.1 Flash 1017

deepseek/deepseek-v4.1-flash-1017 · DeepSeekDeclared and measured agree
Tokenizer group (measured)
DeepSeek
Declared tokenizer tag
DeepSeek
Entered catalogue
17 October 2026
Last tested
17 October 2026
Evidence confidence
High

Why high: an exact fingerprint shared with 14 models that declare the same family, without a second signal of a different kind yet.

Evidence
  • ✓ exact tokenizer signature shared with 14 models
Compare with DeepSeek: DeepSeek V4.1 Flash

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Identity statement

DeepSeek: DeepSeek V4.1 Flash 1017 is DeepSeek's model, and its measured tokenizer sits in DeepSeek's own signature group alongside its sibling models. Measured models from StepFun carry the same vocabulary, which reads as reuse of DeepSeek's tokenizer line and questions nobody's authorship; they are listed under "Shares this fingerprint" below.

What we checked

Four different kinds of evidence, and what each one showed
We checkedWhat we foundWhere it came from
How it counts tokensCounts every one of the 50 test strings exactly like 14 other modelstk_73c4f0dc
How its API is set upA combination of settings no other listing in the catalogue usesapi_a2acb797
How much it can read and writeReads up to 1,048,576 tokens at once, writes up to 393,216its own listing
Whether it thinks before answeringReasons when asked to, at max, high, low, none, high by defaultits own listing
Who served our requestsInferenceNetwe measured it, 17 October 2026

Shares this fingerprint

Exact signature first; template-boundary shifts of the same signature beneath
DeepSeek: DeepSeek V3 0324deepseek/deepseek-chat-v3-0324exact · 50/50DeepSeek: R1 0528deepseek/deepseek-r1-0528exact · 50/50DeepSeek: DeepSeek V3.1 Terminusdeepseek/deepseek-v3.1-terminusexact · 50/50DeepSeek: DeepSeek V3.2deepseek/deepseek-v3.2exact · 50/50DeepSeek: DeepSeek V3.2 Expdeepseek/deepseek-v3.2-expexact · 50/50DeepSeek: DeepSeek V4 Flash 0423deepseek/deepseek-v4-flashexact · 50/50DeepSeek: DeepSeek V4 Flash 0731deepseek/deepseek-v4-flash-0731exact · 50/50DeepSeek: DeepSeek V4 Flash Vision Expdeepseek/deepseek-v4-flash-vision-expexact · 50/50DeepSeek: DeepSeek V4 Pro 0423deepseek/deepseek-v4-proexact · 50/50DeepSeek: DeepSeek V4 Pro 0813deepseek/deepseek-v4-pro-0813exact · 50/50DeepSeek: DeepSeek V4.1 Flashdeepseek/deepseek-v4.1-flashexact · 50/50StepFun: Step 3.5 Flashstepfun/step-3.5-flashexact · 50/50StepFun: Step 3.7 Flashstepfun/step-3.7-flashexact · 50/50StepFun: Step 5 Previewstepfun/step-5-previewexact · 50/50DeepSeek: DeepSeek V3deepseek/deepseek-chatsame tokenizer · template shiftDeepSeek: DeepSeek V3.1deepseek/deepseek-chat-v3.1same tokenizer · template shiftDeepSeek: R1 Distill Llama 70Bdeepseek/deepseek-r1-distill-llama-70bsame tokenizer · template shift

Closest measured models

Agreement across the mutually clean test strings
DeepSeek: DeepSeek V4 Pro 0813deepseek/deepseek-v4-pro-081350/50 · 100%DeepSeek: DeepSeek V4 Flash Vision Expdeepseek/deepseek-v4-flash-vision-exp50/50 · 100%DeepSeek: DeepSeek V4 Flash 0731deepseek/deepseek-v4-flash-073150/50 · 100%DeepSeek: DeepSeek V4 Flash 0423deepseek/deepseek-v4-flash50/50 · 100%StepFun: Step 3.5 Flashstepfun/step-3.5-flash50/50 · 100%StepFun: Step 3.7 Flashstepfun/step-3.7-flash50/50 · 100%

Click a row to open the full comparison.

The measured fingerprint

What each test string cost this model, in tokens

We sent DeepSeek: DeepSeek V4.1 Flash 1017 fifty short pieces of text and recorded what each one cost it in tokens. The bars below are those costs. Two models built on the same tokenizer produce the same bars; a model built on a different one produces a different set, which is what makes this a fingerprint.

All 50 rows

English and whitespace

en-prose14
en-long16
spaces-203
spaces-603
tabs-204
newlines-204
mixed-ws7

Digits

digits-93
digits-124
digits-3010
digits-sep7
float-long9

CJK

zh-common9
zh-long10
zh-rare18
ja-kana9
ja-kanji11
ko13

Other scripts

ru13
ar10
he14
hi18
th11
el16

Emoji

emoji-basic10
emoji-skin14
emoji-zwj-family11
emoji-zwj-x333
emoji-flags16
emoji-prof19

Rare Unicode

math22
boxdraw27
combining10
cjk-ext-b16
surrogates33
zalgo36
rtl-mix6

Code

py-code25
py-indent15
json20
html16
regex47
camel7
snake8

Repetition and encodings

rare-word-x526
repeat-tok41
base6434
hex12
url17
uuid27

Overhead subtracted: 30 prompt tokens.

Declared record

What the catalogue claims about this model

DeepSeek V4.1 Flash 1017 is the October 17, 2026 snapshot of DeepSeek V4.1 Flash, served by DeepSeek under the `deepseek-flash` API model name. V4.1 Flash is a sparse mixture-of-experts model...

Modalities
text+image->text
Declared tokenizer
DeepSeek
Prompt price
$0.15 / M tokens
Completion price
$0.60 / M tokens

Supported parameters

frequency_penaltyinclude_reasoninglogit_biaslogprobsmax_tokensmin_ppresence_penaltyreasoningreasoning_effortrepetition_penaltyresponse_formatseedstopstructured_outputstemperaturetool_choicetoolstop_ktop_logprobstop_p

Default settings

No values declared

Catalogue entryWeights on Hugging Face

History

Every observation, kept as taken
  • 17 October 2026Enters the OpenRouter catalogue declared as DeepSeek.
  • 17 October 2026Fingerprinted in the YFarmX catalogue sweep · 50 of 50 strings measured clean.
  • 17 October 2026YFarmX assessment: consistent with the DeepSeek family, high confidence.