Seed 1.6
Seed 1.6 is a sparse Mixture-of-Experts (MoE) model with 23B active parameters out of 230B total, a context window of 256K tokens, and three reasoning modes including adaptive chain-of-thought (CoT) that calibrates thinking depth to question complexity. Your use is subject to ByteDance's Terms & Privacy Policies.
View API reference- Input and output price
- Input $0.25, Output $2, Per 1M tokens
- 24h uptime
- Loading AI Gateway uptime
import { streamText } from 'ai'
const result = streamText({ model: 'bytedance/seed-1.6', prompt: 'Why is the sky blue?'})Copy link to headingPlayground
Try out Seed 1.6 by ByteDance. Usage is billed to your team at API rates. Free users (those who haven't made a payment) get $5 of credits every 30 days.
Seed 1.6
Seed 1.6
Copy link to headingProviders
Route requests across multiple providers. Copy a provider slug to set your preference. Visit the docs for more info. Using a provider means you agree to their terms, listed under Legal.
Copy link to headingUptime24 hours
Direct request success rate on AI Gateway and per-provider. Visit the docs for more info.
Copy link to headingThroughput24 hours
P50 throughput on live AI Gateway traffic, in tokens per second (TPS). Visit the docs for more info.
Copy link to headingLatency24 hours
P50 time to first token (TTFT) on live AI Gateway traffic, in milliseconds. View the docs for more info.
Getting started
Call Seed 1.6 through AI Gateway with the AI SDK generateText and streamText functions, or through the OpenAI Chat Completions, OpenAI Responses, and Anthropic Messages APIs by changing the base URL. AI Gateway authenticates the request and routes it to an available provider.
Install the AI SDK (pnpm add ai dotenv), create an API key from the API Keys page, and set it as AI_GATEWAY_API_KEY in your environment. Full setup is covered in the text generation quickstart.
import { generateText } from 'ai';import 'dotenv/config';
async function main() { const result = await generateText({ model: 'bytedance/seed-1.6', prompt: 'Why is the sky blue?', });
console.log(result.text);}
main().catch(console.error);Top-level parameters
The same Seed 1.6 request in each API format AI Gateway supports.
import { generateText } from 'ai';import 'dotenv/config';
async function main() { const result = await generateText({ model: 'bytedance/seed-1.6', system: 'You are a concise technical assistant.', prompt: 'Summarize the tradeoffs between static generation and SSR.', maxOutputTokens: 1024, });
console.log(result.text);}
main().catch(console.error);Standard parameters like prompt, messages, temperature, and tools work as documented in the AI SDK docs. These are the parameters with model-specific behavior.
| Parameter | Type | Required | Description |
|---|---|---|---|
model | string | Yes | Model ID in the form creator/model, e.g. bytedance/seed-1.6. AI Gateway routes the request to an available provider. |
maxOutputTokens | number | No | Hard cap on generated tokens. Seed 1.6 supports up to 32,000 output tokens. Reasoning tokens count toward this limit. |
reasoning | 'provider-default' | 'none' | 'minimal' | 'low' | 'medium' | 'high' | 'xhigh' | No | Provider-agnostic reasoning effort, available in AI SDK 7 or later. Maps to the provider’s native reasoning configuration; reasoning settings under providerOptions take precedence when both are set. See the Reasoning section below. |
providerOptions | Record<string, JSONValue> | No | AI Gateway routing options under gateway, plus any provider-native options under the provider’s own namespace — see the table below. |
Input limits
| Input | Formats | Sources | Max count | Max size | Limits |
|---|---|---|---|---|---|
| Text | — | — | — | — | Prompt and response share the 256K-token context window |
| Image | — | URL, base64, Uint8Array | — | — | Sent as image parts in messages; counts as input tokens |
Provider options
Set AI Gateway routing options under providerOptions.gateway. For provider-specific options, pass them under the provider’s namespace as documented by the AI SDK.
Learn more in the AI SDK provider docs.
import { generateText } from 'ai';import 'dotenv/config';
async function main() { const result = await generateText({ model: 'bytedance/seed-1.6', prompt: 'Why is the sky blue?', providerOptions: { gateway: { only: ['bytedance'], }, }, });
console.log(result.text);}
main().catch(console.error);These AI Gateway routing options apply to every model. Provider-specific options pass through under the provider’s own namespace (for example providerOptions.anthropic) exactly as documented by the AI SDK.
| Parameter | Type | Required | Description |
|---|---|---|---|
providerOptions.gateway.only | string[] | No | Restrict routing to these provider slugs. Requests fail over only within the listed providers. |
providerOptions.gateway.order | string[] | No | Preferred provider order. Listed providers are tried first; unlisted providers remain available as fallbacks. |
providerOptions.gateway.sort | 'cost' | 'ttft' | 'tps' | No | Rank candidate providers by price, time to first token, or tokens per second instead of the default routing order. |
providerOptions.gateway.zeroDataRetention | boolean | No | Route only to providers with a zero-data-retention policy for this model. |
Routing across providers
AI Gateway serves the same model through multiple providers and fails over automatically. order expresses a preference while keeping every provider eligible; only is a hard allowlist — if none of the listed providers are available the request fails instead of falling back.
Options under a provider's own namespace (for example providerOptions.anthropic) are forwarded to that provider with the request. Providers ignore option namespaces that don't apply to them, so it is safe to set provider options alongside gateway routing options.
Reasoning
AI Gateway bridges reasoning across every API format. The AI SDK exposes a provider-agnostic top-level reasoning level (none, minimal, low, medium, high, or xhigh); the Chat Completions and Responses formats take the same effort under reasoning.effort; and the Anthropic Messages format uses a native thinking token budget. Whichever you send, the gateway maps it to the target model’s native configuration, converting between effort levels and token budgets as needed. Reasoning-related settings under providerOptions take full precedence over the top-level reasoning value and are never merged. Reasoning tokens typically count toward your output-token usage, though how they’re reported and billed varies by provider.
Learn more in the AI Gateway reasoning guide.
import { generateText } from 'ai';import 'dotenv/config';
async function main() { const result = await generateText({ model: 'bytedance/seed-1.6', prompt: 'Explain the Monty Hall problem step by step.', reasoning: 'high', });
console.log(result.text);}
main().catch(console.error);Image input
Send images alongside text as message parts. Images count as input tokens.
import { generateText } from 'ai';import 'dotenv/config';
async function main() { const result = await generateText({ model: 'bytedance/seed-1.6', messages: [ { role: 'user', content: [ { type: 'text', text: 'Describe this image.' }, { type: 'image', image: 'https://example.com/photo.jpg' }, ], }, ], });
console.log(result.text);}
main().catch(console.error);Tool calling
Expose tools the model can call. Define each tool’s inputs with a Zod schema.
import { generateText, tool } from 'ai';import { z } from 'zod';import 'dotenv/config';
async function main() { const result = await generateText({ model: 'bytedance/seed-1.6', prompt: 'What is the weather in San Francisco?', tools: { getWeather: tool({ description: 'Get the current weather for a location', inputSchema: z.object({ location: z.string() }), execute: async ({ location }) => ({ location, temperatureC: 18 }), }), }, });
console.log(result.text);}
main().catch(console.error);Copy link to headingMore models by ByteDance
| Model |
|---|
| — | $0.003/M | $0.04/img | — | | 07/11/2026 | |||||||||
| 262K | 1.4 s | 122 tps | $0.50/M | $2.50/M | Read$0.10/M | — | | 06/23/2026 | ||||||
| — | $0.04/img | — | | 02/13/2026 | ||||||||||
| — | $0.04/img | — | | 12/03/2025 | ||||||||||
| — | $0.03/img | — | | 09/09/2025 | ||||||||||
| 256K | 1.1 s | 141 tps | $0.25/M+1 more | $2/M+1 more | Read$0.05/M | — | | 09/01/2025 |
Copy link to headingAbout Seed 1.6
Seed 1.6 uses a sparse Mixture-of-Experts (MoE) architecture with 23B active parameters drawn from 230B total. It builds on MoE design principles from ByteDance's Seed 1.5 research. Only the parameter subset most relevant to each token activates during inference, which keeps costs closer to a 23B dense model than a 230B one.
Seed 1.6 offers three reasoning modes. FullCoT enables extended chain-of-thought for demanding analytical problems. NoCoT produces direct completions without a visible reasoning trace, suited to latency-sensitive applications. AdaCoT, the adaptive mode, decides whether reasoning tokens are warranted based on inferred question difficulty. It saves compute on simple queries while engaging deeper reflection when the problem demands it. A parallel decoding enhancement also generates additional thinking tokens without retraining, yielding eight-point improvements on the BeyondAIME benchmark.
The context window of 256K tokens supports long-document processing and multimodal input. On China's 2025 Gaokao, Seed 1.6 scored 683/750 in humanities (ranked first) and 648/750 in science (ranked second), rising to 676/750 with higher-resolution images. On India's JEE Advanced entrance exam, the model placed in the top 10 with 100% accuracy in math across all five sampling rounds.
See https://console.byteplus.com/ark/region:ark+ap-southeast-1/model/detail?Id=seed-1-6 for the full write-up, tables, and methodology.
Copy link to headingWhat To Consider When Choosing a Provider
- Configuration: If your workload relies on extended thinking, confirm that your chosen provider exposes the full reasoning token budget without truncation. Compare token pricing ($0.25 in, $2 out per million tokens when listed).
- Zero Data Retention: Zero Data Retention is offered on a per-provider and model basis. See the documentation for details.
- Authentication: AI Gateway authenticates requests using an API key or OIDC token. You do not need to manage provider credentials directly.
Copy link to headingWhen to Use Seed 1.6
Best for
- Long-document analysis: The context window of 256K tokens lets you ingest entire contracts, research papers, or codebases in one prompt
- Mixed-difficulty workloads:
AdaCoTcalibrates compute spend automatically, routing complex queries to full reasoning and simple ones to direct response - Multimodal pipelines: Integrated VLM capability combines text and visual data in the same request
- GUI-based interaction: Tasks that require understanding screenshots or interface layouts alongside natural language instructions
- Competitive academic domains: Mathematics, science, and humanities workloads where benchmark results confirm consistent performance
Consider alternatives when
- Pure text generation: A dense model may offer more predictable routing behavior when no visual input is involved
- Output length limits: Requests needing more than 32K tokens in a single response exceed capacity
- Deterministic latency: Pipelines can't tolerate variable thinking token overhead from
FullCoTorAdaCoT - Cost-sensitive workloads: A smaller distilled model may meet your quality bar at lower cost per token
Copy link to headingConclusion
Seed 1.6 combines a context window of 256K tokens, sparse MoE efficiency, and three reasoning modes in one deployment. If you previously needed separate fast and slow models, you can consolidate onto a single endpoint and let AdaCoT manage the tradeoff at inference time.
Copy link to headingFrequently Asked Questions
What are the three reasoning modes in Seed 1.6 and when should I use each?
The three modes are
FullCoT,NoCoT, andAdaCoT.FullCoTgenerates an extended chain-of-thought trace before answering, best for complex multi-step problems.NoCoTskips the reasoning trace for direct, low-latency responses.AdaCoTselects between the two based on estimated question difficulty, making it the practical default for mixed workloads.Does Seed 1.6 support image inputs?
Yes. Seed 1.6 incorporates Vision-Language Model (VLM) capabilities. You can process both text and visual data in the same request.
What is parallel decoding in the context of Seed 1.6?
It's a training-free inference enhancement that generates additional thinking tokens without changing the base model weights. It deepens reasoning capacity at inference time, yielding eight-point improvements on the BeyondAIME benchmark.
How does the sparse MoE architecture affect cost?
Only 23B of the 230B total parameters activate per forward pass. Inference compute stays closer to a 23B dense model than a 230B one. This lowers per-token cost while retaining the representational capacity of the full parameter count.
What academic benchmarks were used to evaluate Seed 1.6?
ByteDance evaluated Seed 1.6 on China's 2025 Gaokao (683/750 in humanities, ranked first; 648/750 in science, ranked second, rising to 676/750 with higher-resolution images) and India's JEE Advanced entrance exam (top-10 placement, 100% math accuracy across five sampling rounds). See https://console.byteplus.com/ark/region:ark+ap-southeast-1/model/detail?Id=seed-1-6 for the full tables.
Is Seed 1.6 available for commercial use through AI Gateway?
Yes. You can access Seed 1.6 through ByteDance via AI Gateway with an API key or OIDC token. You don't manage upstream provider credentials yourself.