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Qwen: Qwen3.8 27B

qwen/qwen3.8-27b · Alibaba (Qwen)Declared and measured agree
Tokenizer lineage (measured)
Qwen
Declared tokenizer tag
Qwen
Entered catalogue
14 August 2026
Last tested
5 October 2026
Evidence confidence
High

Why high: an exact fingerprint shared with 5 models that declare the same family, without a second signal of a different kind yet.

Evidence
  • ✓ exact tokenizer signature shared with 5 models

Identity statement

Qwen: Qwen3.8 27B is Alibaba (Qwen)'s model. Its measured tokenizer sits with the Qwen group, which is evidence that it builds on the Qwen tokenizer. Tokenizer reuse is normal engineering, open vocabularies travel between labs, and this says nothing against Alibaba (Qwen)'s authorship of the model itself.

Verification note

Checked against the primary artefacts, 5 October 2026

Re-measured on 5 October 2026 on four providers one at a time: Reka, CoreWeave, Parasail and Chutes. The 21 August reading was taken while OpenRouter spread the calls across eight providers, and five of its rows (English prose, Hindi, the emoji sequence, the mathematical-alphabet string and the UUID) came back four or five tokens below what every provider reports on its own. The four single-provider readings agree with each other, and the corrected record matches Qwen 3.6 27B and Qwen 3.6 35B exactly on all 50 strings: Qwen 3.8 27B ships the Qwen 3.6 vocabulary. The record counts that as a changed fingerprint because the August numbers were published; the vocabulary behind the name did not move.

Qwen 3.8 27B on OpenRouter

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 5 other modelstk_06ffa14a
How its API is set upA combination of settings no other listing in the catalogue usesapi_e620ed95
How much it can read and writeReads up to 1,000,000 tokens at once, writes up to 131,072its own listing
Whether it thinks before answeringReasons when asked to, at xhigh, medium, low, xhigh by defaultits own listing
Who served our requestsRekawe measured it, 5 October 2026
Measured twiceBetween 21 August 2026 and 5 October 2026, 5 of 50 strings changed count in a pattern no template explains: a different tokenizer now answers under this name.45/50 agree

Shares this fingerprint

Exact signature first; template-boundary shifts of the same signature beneath

Closest measured models

Agreement across the mutually clean test strings

Click a row to open the full comparison.

The measured fingerprint

What each test string cost this model, in tokens

We sent Qwen: Qwen3.8 27B 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-203
newlines-204
mixed-ws5

Digits

digits-99
digits-1212
digits-3030
digits-sep12
float-long22

CJK

zh-common9
zh-long10
zh-rare18
ja-kana7
ja-kanji10
ko13

Other scripts

ru12
ar10
he14
hi20
th12
el13

Emoji

emoji-basic9
emoji-skin30
emoji-zwj-family18
emoji-zwj-x354
emoji-flags24
emoji-prof29

Rare Unicode

math29
boxdraw28
combining5
cjk-ext-b13
surrogates40
zalgo36
rtl-mix6

Code

py-code26
py-indent18
json25
html16
regex44
camel5
snake6

Repetition and encodings

rare-word-x530
repeat-tok21
base6436
hex17
url19
uuid36

Overhead subtracted: 52 prompt tokens.

Declared record

What the catalogue claims about this model

Qwen3.8 27B is an open-weight dense vision-language model from Qwen. It is suited for coding, professional workflows, research, multimodal interaction, and long-running agent tasks, with flexible thinking that can be...

Modalities
text+image+video->text
Declared tokenizer
Qwen
Prompt price
$0.42 / M tokens
Completion price
$2.55 / M tokens

Supported parameters

frequency_penaltyinclude_reasoninglogit_biaslogprobsmax_tokensmin_ppresence_penaltyreasoningreasoning_effortrepetition_penaltyresponse_formatseedstopstructured_outputstemperaturetool_choicetoolstop_atop_ktop_logprobstop_p

defaults: {"temperature":1,"top_p":0.95,"top_k":20}

Catalogue entryWeights on Hugging Face

History

Every observation, kept as taken
  • 14 August 2026Enters the OpenRouter catalogue declared as Qwen.
  • 21 August 2026Fingerprinted in the YFarmX catalogue sweep · 50 of 50 strings measured clean.
  • 5 October 2026Fingerprinted again, to check the reading held · 50 of 50 strings measured clean.
  • 5 October 2026Fingerprinted again, to check the reading held · 50 of 50 strings measured clean.
  • 5 October 2026Fingerprinted again, to check the reading held · 50 of 50 strings measured clean.
  • 5 October 2026Fingerprinted again, to check the reading held · 50 of 50 strings measured clean.
  • 5 October 2026Fingerprinted again, to check the reading held · 50 of 50 strings measured clean.
  • 5 October 2026YFarmX assessment: consistent with the Qwen family, high confidence.