Google: Gemini 2.5 Flash

google/gemini-2.5-flash · GoogleUnmeasurable
Declared family
Gemini
Evidence confidence
Unknown
Declared tokenizer tag
Gemini
Entered catalogue
17 June 2025
Last tested
21 August 2026
Measurement
Unmeasurable: prompt caching corrupts its token accounting

Evidence stack

Signals of different kinds, weighed together
SignalResultReference
Tokenizer signatureNot measured
API surfaceIdentical contract to 1 other entryapi_742308b0
Context and output1,048,576 context · 65,535 max outputdeclared
Reasoning contractOptionaldeclared
Serving providers observedGooglemeasured 21 August 2026

Closest measured models

Agreement across the mutually clean test strings

Click a row to open the full comparison.

The measured fingerprint

Marginal prompt-token cost of each test string, grouped by script
All 50 rows, 24 excluded as corrupt

English and whitespace

en-prose14
en-long16
spaces-203
spaces-604
tabs-203
newlines-203
mixed-ws9

Digits

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

CJK

zh-common10
zh-long12
zh-rare25
ja-kana7
ja-kanji9
ko11

Other scripts

ru12
ar10
he13
hi8
th10
el13

Emoji

emoji-basic5
emoji-skin10
emoji-zwj-familyx
emoji-zwj-x3x
emoji-flagsx
emoji-profx

Rare Unicode

mathx
boxdrawx
combiningx
cjk-ext-bx
surrogatesx
zalgox
rtl-mixx

Code

py-codex
py-indentx
jsonx
htmlx
regexx
camelx
snakex

Repetition and encodings

rare-word-x5x
repeat-tokx
base64x
hexx
urlx
uuidx

An x marks a row excluded as corrupt (caching or provider interference detected during measurement). Overhead subtracted: 0 prompt tokens.

Declared record

What the catalogue claims about this model

Gemini 2.5 Flash is Google's state-of-the-art workhorse model, specifically designed for advanced reasoning, coding, mathematics, and scientific tasks. It includes built-in "thinking" capabilities, enabling it to provide responses with greater...

Modalities
text+image+file+audio+video->text
Declared tokenizer
Gemini
Prompt price
$0.30 / M tokens
Completion price
$2.50 / M tokens

Supported parameters

include_reasoningmax_tokensreasoningresponse_formatseedstopstructured_outputstemperaturetool_choicetoolstop_p

defaults: {"temperature":null,"top_p":null,"top_k":null,"frequency_penalty":null,"presence_penalty":null,"repetition_penalty":null}

Catalogue entry

History

Every observation, kept as taken
  • 17 June 2025Enters the OpenRouter catalogue declared as Gemini.
  • 21 August 2026Fingerprinted in the YFarmX catalogue sweep · 26 of 50 strings measured clean.

Cite this page as the evidence record for Google: Gemini 2.5 Flash: the URL is stable, measurements are dated, and revisions append to the history above. Method: tokenizer fingerprinting, v1, 50 strings. The raw data behind every figure is on the data page.