Seed 1.8 API

ByteDance Seed 1.8 is a large language model with a 256K context window optimized for long-context reasoning and generation.

Modalities
Image, TextText
In / Out price
$0.25/$2per 1M
Context window
250K tokens
Released
Jan 12, 2026

Seed 1.8 overview

The pelican test: one prompt, every text model, unedited SVG output from Nov 3, 2026.

SVG of a pelican riding a bicycle, written by Seed 1.8 through AI/ML API

Seed 1.8 specs

Model ID
bytedance/seed-1-8
Developer
ByteDance
Context window
256,000 tokens
Max output
224,000 tokens
Input
Image, Text
Output
Text
API
OpenAI-compatible, base URL https://api.aimlapi.com/v1

ByteDance Seed 1.8 is a large language model with a 256K context window optimized for long-context reasoning and generation.

Coding and code review
Generate, debug, and review code across languages, reading whole files or repos in a single prompt.

Agentic and multi-step workflows
Reliable tool-calling and instruction-following suit agent loops that plan, call tools, and iterate.

Long-document analysis
Summarize and extract from contracts, papers, and reports without aggressive chunking.

Use cases

Seed 1.8 is documented as suited to information retrieval, where it can gather and reconcile information across several steps. It is also suited to code generation and execution, including tasks where a coding agent generates a script, checks execution results, and revises the code after an error.

It is documented as suited to GUI interaction, where it can interpret screenshots or software interfaces and determine the next permitted action. It is also suited to complex workflows and multi-step task execution, including internal automation systems that coordinate several controlled tools and document workflows that combine long context, visual pages, and follow-up actions.

Capabilities

  • Function calling
  • Streaming
  • Structured outputs

Seed 1.8 API pricing

Seed 1.8 pricing in US dollars
UsagePriceUnit
Input$0.251M tokens
Output$21M tokens

Prices from the AI/ML API price list, checked on Nov 4, 2026.

Seed 1.8 vs other models: token prices

AI/ML API input and output rates for 5 models, per million tokens.

AI/ML API model prices in USD per million tokens
ModelInputOutput
Seed 1.8$0.25$2
Dola-Seed 2.0 Mini$0.1$0.4
Dola-Seed 2.0 Lite$0.25$2
Seed 2.1 Turbo$0.529$2.65
Seed 2.0 Code$0.529$3.17

How to use the Seed 1.8 API

View docs

Build with your agent

Give your agent the model details, code and documentation.

1Get your API key

Create API key
export AIMLAPI_KEY="8f2b4c7d9a1e6b3f…"

2Make your first request

curl 'https://api.aimlapi.com/v1/chat/completions' \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "bytedance/seed-1-8",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about the ocean."
    }
  ]
}'

Seed 1.8 FAQ

What is the context window of Seed 1.8?

Seed 1.8 has a 256,000 tokens context window and can return up to 224,000 tokens.

What inputs and outputs does Seed 1.8 support?

Seed 1.8 takes image, text as input and returns text.

What is the model ID for Seed 1.8?

Use bytedance/seed-1-8 as the model id. Requests go to https://api.aimlapi.com/v1/chat/completions.

How much does Seed 1.8 cost?

Seed 1.8 costs $0.25 input and $2 output per 1M tokens on AI/ML API, billed as you go with no subscription.

Does Seed 1.8 support streaming?

Yes, Seed 1.8 can stream responses as they are generated.

Can Seed 1.8 read images?

Yes, Seed 1.8 accepts image input alongside text.

Who created Seed 1.8?

Seed 1.8 was built by ByteDance.

What capabilities does Seed 1.8 offer?

It supports function calling, streaming, structured outputs, parallel tool calls, and vision input alongside text.

Start building with Seed 1.8

Seed 1.8 API

bytedance/seed-1-8

Build with your agent

Give your agent the model details, code and documentation.

1Get your API key

Create API key
export AIMLAPI_KEY="8f2b4c7d9a1e6b3f…"

2Make your first request

curl 'https://api.aimlapi.com/v1/chat/completions' \
  -H "Authorization: Bearer $AIMLAPI_KEY" \
  -H 'Content-Type: application/json' \
  -d '{
  "model": "bytedance/seed-1-8",
  "messages": [
    {
      "role": "user",
      "content": "Write a haiku about the ocean."
    }
  ]
}'