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FLUX.2 Flexvs.Seedream 4.5

Which one is better?

In our own test, FLUX.2 Flex leads. Seedream 4.5 has no arena rating yet. Seedream 4.5 has no API price.

Test images

Same task, the first image of each. The task with the biggest difference is preselected.

FLUX.2 Flex: Character and detail, first image from the fixed test run
FLUX.2 Flex75 out of 100
Seedream 4.5: Character and detail, first image from the fixed test run
Seedream 4.537 out of 100

Result for “Character and detail”:FLUX.2 Flex ahead

Prompt given to both modelsCreate a square cinematic full-body portrait of a fictional bicycle courier waiting under a transparent umbrella at a rainy tram stop in Hamburg at blue hour. She wears a mustard raincoat, navy trousers, red sneakers, a silver helmet, and carries a teal messenger bag. Keep both hands visible, render the bicycle correctly, use realistic wet-street reflections, and include no readable brand names.

What the rating looks at: Anatomy, clothing, and spatial consistency.

“Ahead”: better in all three rating rounds. “Slightly ahead”: a higher value, but not in every round.

Test protocol of the images

Each test attempt uses the same archived prompt and one request. The first output of that attempt counts. Repeats after technical test failures are disclosed for the affected images. Files are normalized to 1,024 × 1,024 pixels without cropping. Provider resolution, randomness, quality tier and prompt processing can still differ. The images are a practical visual test, not a reconstruction of the arena configuration.

Character and detail

FLUX.2 Flex: together, 1024x1024, n=1, seed=provider random, provider default steps, generated Aug 14, 2026, 12:25 PM. Source

Seedream 4.5: fal, requested native 2048x2048 square, n=1, seed=607017308, estimated cost $0.040000, source 2048x2048, stored 1024x1024 (Lanczos3 downscale), generated Nov 2, 2026, 2:50 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: 985a75b38642a9f0e5e0c0e0c67f1b7f67780d42bd2168fa24e9a7a7a94b0da6

FLUX.2 Flex image SHA 256: 43b43d5782192d7284de2b824dd1caaaa6b25032d22fc3f8565d438b137089f3

Seedream 4.5 image SHA 256: 614d5b810be9f7cc54c999fb930e5bb1a7a5b58f7211a3b71aa92e83a360cf78

Infographic

FLUX.2 Flex: together, 1024x1024, n=1, seed=provider random, provider default steps, generated Aug 14, 2026, 12:25 PM. Source

Seedream 4.5: fal, requested native 2048x2048 square, n=1, seed=467481828, estimated cost $0.040000, source 2048x2048, stored 1024x1024 (Lanczos3 downscale), generated Nov 2, 2026, 2:51 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: ed65cb4e6a51e2336f8b149ad4cbb16e020f07d527ad94362e719d2dcf91d94f

FLUX.2 Flex image SHA 256: 105f60cdeb71a27021ffff1ad3c0ad919df4e5c74ad83b4628fbd64a8d795a09

Seedream 4.5 image SHA 256: ec1e2be1080670edf050cff00a094ff471c1b480a11a3922cf8c25f0ef0f6a5e

Product photography

FLUX.2 Flex: together, 1024x1024, n=1, seed=provider random, provider default steps, generated Aug 14, 2026, 12:25 PM. Source

Seedream 4.5: fal, requested native 2048x2048 square, n=1, seed=1880157282, estimated cost $0.040000, source 2048x2048, stored 1024x1024 (Lanczos3 downscale), generated Nov 2, 2026, 2:50 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: c67fd71e91304458a2feef5c91efa8677260fab0c0099a29a2c52cb579f5b2f3

FLUX.2 Flex image SHA 256: 9fef39b1500635ddbf78bcb8d3d9a68463ce952aa1fab89d12f6efe023907de7

Seedream 4.5 image SHA 256: 48a36dede8c680fa8e2231ac33a95b1417dcded96ad753c98218cc78ed96a65b

Typography and layout

FLUX.2 Flex: together, 1024x1024, n=1, seed=provider random, provider default steps, generated Aug 14, 2026, 2:01 PM. Source

Seedream 4.5: fal, requested native 2048x2048 square, n=1, seed=775629027, estimated cost $0.040000, source 2048x2048, stored 1024x1024 (Lanczos3 downscale), generated Nov 2, 2026, 2:50 PM. Source

Protocol gradually-image-comparison-v1. Prompt SHA 256: 2e012c3d14ee5dd02203a94f394ca80a5038cdebd6032b25a8b8a221f2255419

FLUX.2 Flex image SHA 256: 324f87bf898593446a400abb43bd00eee015fa0a1dc160db0f864402fc0b38af

Seedream 4.5 image SHA 256: 62d4e5b0b3c9ca5a55952dc2c5aca878ed687c76f302ad632136bd3e6bee3872

The numbers at a glance

Arena ratingfrom votes by users · higher is better
1,156

FLUX.2 Flex

Rank 16 of 21

n/a

Seedream 4.5

not in the arena

GraduallyBenchour own rating, 0 to 100 · higher is better
73

FLUX.2 Flex

Rank 11 of 108

48

Seedream 4.5

Rank 64 of 108

Price per imagedollars through the API · lower is better
$0.06

FLUX.2 Flex

fairly cheap

n/a

Seedream 4.5

no API price

Ranks among the 21 image models with an arena rating and the 108 with a GraduallyBench run; prices compared with 28 models with an API price.

FLUX.2 Flex

Subscription
No Black Forest Labs subscription includes this model. Through other providers from €6.83 a month (Poe Basic, with limited points). 26 plans in Germany.
Via API
$0.06 per image, 100 images $6.

Seedream 4.5

Subscription
No ByteDance / Volcengine subscription includes this model. Through other providers from ≈ €6.36 a month (ElevenLabs Starter, with limited credits). 39 plans in Germany.
Via API
No API price known. Access: API, Web app.
Weights
unknown.

Subscriptions only count plans that name exactly this model. Subscription prices include VAT, API prices are in dollars.

Arena rating (LMArena) from Nov 6, 2026 · GraduallyBench from Nov 3, 2026 · API prices from Nov 6, 2026 · Subscription database from Sep 29, 2026 (38 days old)

All data side by side

The better value is bold. For ratings only when the gap is clear.

KennzahlFLUX.2 FlexSeedream 4.5
Ratings
Arena ratingfrom votes by users, higher is better1,156n/a
Arena rankRank 16 of 21n/a
Arena votesmore votes, a safer rating156,849n/a
GraduallyBenchour own rating, 0 to 1007348
GraduallyBench by task
Typography and layoutLegible text, hierarchy, and composition9884
Product photographyMaterials, reflections, and fine details6344
Character and detailAnatomy, clothing, and spatial consistency7537
InfographicNumbers, labels, and visual organization5727
API price
Per imagelower is better$0.06n/a
100 images$6n/a
Profile
ReleasedNovember 2025n/a
Weightsopen means: runs locallyproprietaryunknown
Lifecycleno noticeStill-listed T2I/I2I model ID; Ark marks it as pending shutdown without giving a date in the reviewed source
AccessAPI, Web appAPI, Web app
Parametersnot publishednot published
Largest output4 Megapixelnot consistently published
Plans in Germanynaming exactly this model2639

API prices for one image at 1,024 × 1,024 pixels according to Artificial Analysis.

Sources: FLUX.2 Flex model source (verified Sep 24, 2026) · Seedream 4.5 model source, status source (verified Nov 1, 2026)

Arena ratings by category

From blind votes on LMArena. “Ahead” means the lead is clear.

No shared arena score in the stored snapshot

The stored benchmark database contains no measurement for FLUX.2 Flex and Seedream 4.5 from the same arena and category. Older model versions are not used as substitutes.

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