Context Window

Compare

Seed 2.1 Turbo vs Step 3.5 Flash

This page is context-first: how much text each model can take in one request. Full specs adds capabilities and limits; the pricing matrix below is only about $/million tokens from hosts that list both models.

Bytedance

Model

Seed 2.1 Turbo

Image inputTool calling

Context window

262K

262,144 tokens · ~197K words

Model page
Stepfun

Model

Step 3.5 Flash

Tool calling

Context window

262K

262,144 tokens · ~197K words

Model page

Context window · side by side

Bar length is relative to the larger of the two windows (100% = max of this pair). This is not pricing.

Seed 2.1 Turbo262K
Step 3.5 Flash262K

Same context window size for both models.

Token calculator →Memory savings →

Seed 2.1 Turbo and Step 3.5 Flash have identical context windows (262K tokens). Step 3.5 Flash is 80% cheaper on input.

Quick verdicts

Short takeaways — validate with your own workloads.

  • RAG / high-volume retrieval

    Use Step 3.5 Flash. Input tokens are 80% cheaper — critical when sending large retrieved contexts.

  • Long output (reports, code files)

    Use Seed 2.1 Turbo. Its 235K max output lets you generate complete artifacts in one request.

Full specs

Context, output, capabilities, and dates. Green highlights the favorable value where we compute a winner.

SpecSeed 2.1 TurboStep 3.5 Flash
Context window262,144 tokens (262K)262,144 tokens (262K)
Max output tokens235,929 tokens (235K)65,536 tokens (65K)
Speed tierBalancedFast
VisionYesNo
Function callingYesYes
Extended thinkingYesYes
Prompt cachingNoNo
Batch APINoNo
Release dateAug 2026Jan 2026

Pricing matrix

Dollar rates only: hosts that list both models, per 1M tokens. For how much text fits, use the context section above — not this table.

ProviderSeed 2.1 Turbo inSeed 2.1 Turbo outStep 3.5 Flash inStep 3.5 Flash out
Openrouter$0.500/M$2.50/M$0.100/M$0.300/M

Frequently asked questions

Step 3.5 Flash has a larger context window: 262K tokens vs 262K. For long documents, large codebases, or extended agent sessions, the larger context window reduces the need to chunk inputs or summarize history.

Powered by Mem0

Use a smaller model.
Get better results.

Mem0 gives your AI long-term memory so you stop re-sending context on every call. That means you can use a smaller, faster, cheaper model — and still get better answers.

Calculate your savingsLearn about Mem0

Example: a multi-turn chat session

Without Mem0~128K tokens sent
Full history
Repeated info
Old context
With Mem0~20K tokens sent
Key memories
Current turn

80% less to send — works with any model