Nano Banana 2.1vs.Seedream 5.0 Flash

Which one is better?

In our own test both are on par. Neither is in the arena. Neither has an API price.

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

Nano Banana 2.1: Character and detail, first image from the fixed test run — Nano Banana 2.167 out of 100

Seedream 5.0 Flash: Character and detail, first image from the fixed test run — Seedream 5.0 Flash34 out of 100

Result for “Character and detail”:Nano Banana 2.1 slightly 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

Both models receive the same archived prompt in exactly one request, and the first result counts. 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

Nano Banana 2.1: openrouter, aspect ratio 1:1, resolution 1K, n=1, seed=provider random, actual cost $0.036408, generated Nov 1, 2026, 9:40 PM. Source

Seedream 5.0 Flash: openrouter, aspect ratio 1:1, resolution 1K, n=1, seed=provider random, actual cost $0.018000, generated Nov 1, 2026, 8:29 PM. Source

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

Nano Banana 2.1 image SHA 256: f89e3f52678670058ce0e1e9b0b5b6ec084e25a212491b5025e76d7525fb8707

Seedream 5.0 Flash image SHA 256: ffb32d701168dd57095e39252aba67b191c008c7b9393ae22acf1e1b1caba9b9

Infographic

Nano Banana 2.1: openrouter, aspect ratio 1:1, resolution 1K, n=1, seed=provider random, actual cost $0.036560, generated Nov 1, 2026, 9:40 PM. Source

Seedream 5.0 Flash: openrouter, aspect ratio 1:1, resolution 1K, n=1, seed=provider random, actual cost $0.018000, generated Nov 1, 2026, 8:30 PM. Source

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

Nano Banana 2.1 image SHA 256: ce5c4b7af2575ccf9964cfeea2e4f0bb75cdad21aea29c4201e693fa307e435b

Seedream 5.0 Flash image SHA 256: 0758d1251491a26b5d7736c16597318e5807a92c30db03d9431d8584652aae3e

Product photography

Nano Banana 2.1: openrouter, aspect ratio 1:1, resolution 1K, n=1, seed=provider random, actual cost $0.036546, generated Nov 1, 2026, 9:39 PM. Source

Seedream 5.0 Flash: openrouter, aspect ratio 1:1, resolution 1K, n=1, seed=provider random, actual cost $0.018000, generated Nov 1, 2026, 8:29 PM. Source

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

Nano Banana 2.1 image SHA 256: 289b144f7d5348e9324d229e5508d5698c09035f2cbdea474845a84b852e859e

Seedream 5.0 Flash image SHA 256: 3ea7343b12d253b6b0e090054c1e494f5a005632cc263a9b2df4d866ba6b02d0

Typography and layout

Nano Banana 2.1: openrouter, aspect ratio 1:1, resolution 1K, n=1, seed=provider random, actual cost $0.036497, generated Nov 1, 2026, 9:39 PM. Source

Seedream 5.0 Flash: openrouter, aspect ratio 1:1, resolution 1K, n=1, seed=provider random, actual cost $0.018000, generated Nov 1, 2026, 8:29 PM. Source

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

Nano Banana 2.1 image SHA 256: d27b58baa4115177a46fae2d71e258c5f4de9243fc66df93983ef6127df2f320

Seedream 5.0 Flash image SHA 256: b9739c9a9ab67183f268f41b7ff62a9151cef9d0c8c168eba332a2b6af057426

The numbers at a glance

Arena ratingfrom votes by users · higher is better

n/a

Nano Banana 2.1

not in the arena

n/a

Seedream 5.0 Flash

not in the arena

GraduallyBenchour own rating, 0 to 100 · higher is better

Nano Banana 2.1

Rank 11 of 74

Seedream 5.0 Flash

Rank 39 of 74

Price per imagedollars through the API · lower is better

n/a

Nano Banana 2.1

no API price

n/a

Seedream 5.0 Flash

no API price

Ranks among the 22 image models with an arena rating and the 74 with a GraduallyBench run; prices compared with 28 models with an API price.

Nano Banana 2.1

Subscription: At Google from €4.99 a month (Google AI Plus, with limited credits). Through other providers from €6.83 a month (Poe Basic, with limited points). 42 plans in Germany.
Via API: No API price known. Access: API, Web app.
Weights: unknown.

Seedream 5.0 Flash

Subscription: No ByteDance subscription includes this model. Through other providers from €6.83 a month (Poe Basic, with limited points). 18 plans in Germany.
Via API: No API price known. Access: API.
Weights: unknown.

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

GraduallyBench from Nov 1, 2026 · Subscription database from Sep 29, 2026 (34 days old)

All data side by side

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

Kennzahl	Nano Banana 2.1	Seedream 5.0 Flash
Ratings
Arena ratingfrom votes by users, higher is better	n/a	n/a
Arena rank	n/a	n/a
Arena votesmore votes, a safer rating	n/a	n/a
GraduallyBenchour own rating, 0 to 100	69	56
GraduallyBench by task
Typography and layoutLegible text, hierarchy, and composition	60	61
Product photographyMaterials, reflections, and fine details	80	49
Character and detailAnatomy, clothing, and spatial consistency	67	34
InfographicNumbers, labels, and visual organization	71	79
API price
Per imagelower is better	n/a	n/a
100 images	n/a	n/a
Profile
Released	Oct 6, 2026	n/a
Weightsopen means: runs locally	unknown	unknown
Access	API, Web app	API
Parameters	not published	not published
Largest output	not consistently published	not consistently published
Plans in Germanynaming exactly this model	42	18

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

Sources: Nano Banana 2.1 model source (verified Nov 1, 2026) · Seedream 5.0 Flash model 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 Nano Banana 2.1 and Seedream 5.0 Flash from the same arena and category. Older model versions are not used as substitutes.

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First image modelSecond image model

More matchups

Compare Nano Banana 2.1 and Seedream 5.0 Flash with other important image models.

View the complete image model comparison

Same prompt, two images

The numbers at a glance

Nano Banana 2.1

Seedream 5.0 Flash

All data side by side

Arena ratings by category

No shared arena score in the stored snapshot

Compare another matchup

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