Bytedance Seed 1.8
Bytedance Seed 1.8 is ByteDance's generalized agentic model. It combines a Search Agent, Code Agent, and GUI Agent in one multimodal system with token-efficient visual encoding and three adaptive thinking modes. 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-1.8', prompt: 'Why is the sky blue?'})Copy link to headingPlayground
Try out Bytedance Seed 1.8 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.
Bytedance Seed 1.8
Bytedance Seed 1.8
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 Bytedance Seed 1.8 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-1.8', prompt: 'Why is the sky blue?', });
console.log(result.text);}
main().catch(console.error);Top-level parameters
The same Bytedance Seed 1.8 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-1.8', 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-1.8. AI Gateway routes the request to an available provider. |
maxOutputTokens | number | No | Hard cap on generated tokens. Bytedance Seed 1.8 supports up to 64,000 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-1.8', 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-1.8', 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-1.8', 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-1.8', 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 | 1.6 s | 106 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 | 1.2 s | 73 tps | $0.25/M+1 more | $2/M+1 more | Read$0.05/M | — | | 09/01/2025 |
Copy link to headingAbout Bytedance Seed 1.8
Bytedance Seed 1.8 integrates three agent functions into one system. The Search Agent handles information retrieval across web and document sources. The Code Agent writes, debugs, and runs code. The GUI Agent interacts with graphical interfaces on desktop, web, and mobile using native vision rather than scripted automation, and operates software the way a human would.
Visual token efficiency is a core engineering focus. Bytedance Seed 1.8 reduces image encoding token requirements without sacrificing reasoning quality. This matters for GUI-heavy workloads where dozens of screenshots may pass through a single session. Three adaptive thinking modes calibrate processing depth to task complexity. They skip unnecessary compute on straightforward steps and use deeper reflection on ambiguous decisions.
In ByteDance's published benchmarks, Bytedance Seed 1.8 reaches 67.6 on BrowseComp-en, 87.8 on VideoMME (long-form video understanding), and 11.0 on ZeroBench (multimodal reasoning). It scores 62.0 on VLMsAreBiased and 47.2 on WorldTravel, up from its predecessor Seed 1.5-VL in those tables. Evaluations cover simulated workflows including travel planning, financial analysis, and software engineering. See https://docs.byteplus.com/en/docs/ModelArk/2123228 for methodology, tables, and comparisons.
Copy link to headingWhat To Consider When Choosing a Provider
- Configuration: For agentic pipelines with repeated GUI observation steps, confirm that your provider supports streaming for incremental processing of long action sequences. 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 Bytedance Seed 1.8
Best for
- Browser and desktop automation: The GUI Agent observes, clicks, types, and navigates interfaces without custom scripting
- Research workflows: Combine live information retrieval with synthesis and code execution in a single agent loop
- Agentic programming: The model writes, tests, and iterates on code autonomously
- Long-form video understanding: Supported by an 87.8 VideoMME score in ByteDance's published results
- Business process automation: Financial analysis, itinerary generation, and document-heavy enterprise workflows
Consider alternatives when
- Single-turn generation: A lighter model would cost less when no agentic component is needed
- Strict JSON validation: Deterministic tool-call schemas require verification of multi-step function calling before production
- Pure text workloads: The model's image encoding overhead wastes compute when no visual inputs are involved
- Formal reasoning specialists: A model optimized for mathematics or formal logic may suit better than a generalized agent
Copy link to headingConclusion
Bytedance Seed 1.8 consolidates search, code, and GUI agency into one model. You don't need separate specialized systems for each capability. Token-efficient visual encoding and adaptive thinking depth make it practical for multi-step pipelines where input modality and task type vary across turns.
Copy link to headingFrequently Asked Questions
What does "generalized agentic model" mean for Bytedance Seed 1.8?
It completes multi-step tasks autonomously across search, code, and graphical interfaces. It covers all three instead of specializing in one capability.
How does the GUI Agent in Bytedance Seed 1.8 work without traditional scripted automation?
It uses native vision to interpret screenshots and decide which actions to take: clicks, keystrokes, and form entries. It adapts to any UI layout without pre-defined selectors or automation scripts.
What is the BrowseComp-en benchmark and why is Bytedance Seed 1.8's score notable?
BrowseComp-en tests retrieval and synthesis through web browsing in English. Bytedance Seed 1.8 scores 67.6 in ByteDance's published table. See https://docs.byteplus.com/en/docs/ModelArk/2123228 for the full benchmark context.
How does token-efficient visual encoding benefit agentic applications?
Each GUI observation step sends one or more screenshots to the model. Fewer tokens per image means more steps fit within the context window at lower cost. This is especially important for long automation sessions with many intermediate observations.
Does Bytedance Seed 1.8 support video understanding in addition to image inputs?
Yes. Bytedance Seed 1.8 scores 87.8 on VideoMME (long-form video understanding) in ByteDance's published results. It processes temporal sequences of visual content alongside text instructions.
What kinds of real-world workflows was Bytedance Seed 1.8 evaluated on?
Evaluations cover simulated practical scenarios including travel planning, financial and business analysis, software engineering tasks, and multi-step information retrieval.
Is Bytedance Seed 1.8 accessible without setting up a Volcano Engine account?
Yes. Through AI Gateway, you authenticate with an API key or OIDC token and route requests to Bytedance Seed 1.8. You don't need a separate Volcano Engine account.