Claude Opus 5.5 vs DeepSeek V4 Flash 0731

rates, context and capabilities side by side on the impossibl api, and what the same workload costs on each.

the models at a glance: base rates, context window and modalities
specificationClaude Opus 5.5

anthropic/claude-opus-5-5

DeepSeek V4 Flash 0731

deepseek/deepseek-v4-flash-0731

input · usd / 1m tok$4.00$0.14
output · usd / 1m tok$20.00$0.28
context window1mtokens1.05mtokens
modalities · in → out

takes text and image in, gives text out

takes text in, gives text out

pricing

base api rates by model
base api rates · usd per 1m tokensClaude Opus 5.5

anthropic/claude-opus-5-5

DeepSeek V4 Flash 0731

deepseek/deepseek-v4-flash-0731

input$4.00$0.14
output$20.00$0.28
cache read$0.20$0.028
cache write · default ttl$5.00not published
cache write · 1h ttl$8.00not published

the estimate below prices one workload at these rates on every model.

specifications

published specifications by model
as publishedClaude Opus 5.5

anthropic/claude-opus-5-5

DeepSeek V4 Flash 0731

deepseek/deepseek-v4-flash-0731

creatorAnthropicDeepSeek
model typeText generationText generation
context window1,000,000tokens1,048,576tokens
input

takes text and image in, gives text out

takes text in, gives text out

outputtexttext
tool callingnot verifiednot verified
releasedsep 22, 2026jul 31, 2026
endpoint/v1/chat/completions/v1/chat/completions

unknown means the public catalog does not establish that fact. a model's documented capabilities can differ from what a particular api supports. see the model documentation for integration details.

benchmarks

benchmark scores by model, primary tested configuration
primary configurationClaude Opus 5.5

anthropic/claude-opus-5-5

no benchmarks yet

DeepSeek V4 Flash 0731

deepseek/deepseek-v4-flash-0731

max effort

intelligence index · gateway ranknot measured34.5#27 of 90
coding indexnot measured69.1#25 of 60
agentic indexnot measured41.7#21 of 49
omnisciencenot measured-14.3#55 of 86
gpqanot measured90.8%#31 of 88
humanity’s last examnot measured38.6%#33 of 89
terminal-bench v2.1not measured78.7%#23 of 57
aa-lcrnot measured79.7%
automationbench partialnot measured54.0%
scicodenot measured50.3%
tau bankingnot measured39.4%
critptnot measured16.6%
multilingual lcrnot measured13.3%
terminal-bench v4.0not measured12.1%
gdp.pdf all-passnot measured11.0%

DeepSeek V4 Flash 0731 source ↗

each column describes the tested configuration named under the model; performance and costs can differ on impossibl. a score one model was not measured on is left blank rather than scored zero. indices are ranked against every model on the gateway with one. last checked 2026-09-11.

estimate your cost

one token workload, priced on every model at the published rates, in usd. change the numbers to match yours.

token workload

total input, including cached tokens

include billable reasoning tokens

the same token usage in each request

a subset of total input, never additional tokens

Claude Opus 5.5

anthropic/claude-opus-5-5

estimated usage cost

$14.00

1,000 requests × (1,000 uncached input × $4.00 + 500 output × $20.00) / 1,000,000 = $14.00

base rates; no context pricing tiers are published.

DeepSeek V4 Flash 0731

deepseek/deepseek-v4-flash-0731

estimated usage cost

$0.28

1,000 requests × (1,000 uncached input × $0.14 + 500 output × $0.28) / 1,000,000 = $0.28

base rates; no context pricing tiers are published.

estimates use published impossibl api usage rates. configured billing adjustments, funding fees, taxes, and custom workspace rates are excluded and may change the final amount.

image and audio usage, cache creation, and additional tool charges are excluded. reasoning tokens count as billable output, even when they are not visible in the response.

summary

Claude Opus 5.5 and DeepSeek V4 Flash 0731 are available through the Impossibl API. they share the /v1/chat/completions endpoint; the model identifier selects the model for a request.

Claude Opus 5.5 is created by Anthropic. It has a 1,000,000-token context window. Base API pricing (USD): $4.00 per million input tokens; $20.00 per million output tokens.

DeepSeek V4 Flash 0731 is created by DeepSeek. It has a 1,048,576-token context window. Base API pricing (USD): $0.14 per million input tokens; $0.28 per million output tokens.

Claude Opus 5.5DeepSeek V4 Flash 0731

this page compares Claude Opus 5.5 vs DeepSeek V4 Flash 0731 as listed by the impossibl public api. prices and availability come from that catalog, refreshed here every five minutes. this is an impossibl offering, not a comparison of independent hosting-provider quotes.

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