Doubleword
    Reasoning
    Structured Generation
    1.0M Context
    FP8
    Z.ai
    Open Weights

    GLM 5.3

    A 1M-context reasoning model built for complex coding and long-running agentic tasks.

    Quantization

    FP8

    Open weights

    Context Window

    1.0M

    Tokens

    Intelligence

    59.5

    AA Index

    Released

    Aug 2026

    25 Aug 2026

    About

    Frontier reasoning, open weights

    GLM 5.3 is Z.ai's open-weight reasoning model for complex coding, long-horizon agentic work, tool use, cybersecurity analysis and repository-scale engineering.

    It provides a 1M-token context window and configurable reasoning effort, so you can dial thinking budget up for hard planning problems and down for high-volume throughput — at a fraction of closed frontier pricing.

    SWE
    Agent
    Tools
    Sec
    Plan
    Long

    1M context · configurable reasoning effort

    Use Cases

    Best for repository-scale engineering

    Complex Coding

    Repository-scale engineering: multi-file edits, large refactors and iterative debugging across long sessions.

    Agentic Workflows

    Configurable reasoning effort for long-horizon planning, tool orchestration and recovery across many steps.

    Cybersecurity Analysis

    Reasoning over codebases, logs and configurations to surface vulnerabilities and explain exploit paths.

    Long-Context Research

    A 1M-token window keeps entire repositories, specs and document sets in a single request.

    Also strong on research synthesis and enhanced structured generation.

    Pricing

    Flexible Pricing Tiers

    Choose the optimal balance of speed and cost for your workflow. Prices are per 1M tokens.

    Tier Input / 1M tokens Output / 1M tokens
    Batch $0.70 $2.20
    Async $1.05 $3.30
    Realtime $1.40 $4.40

    Context window natively supported up to 1,048,576 tokens. We can offer custom pricing for bulk discounts, large workloads, and dedicated deployments — reach out to hello@doubleword.ai.

    Quickstart

    Start Building in Minutes

    GLM 5.3 is accessible via OpenAI-compatible endpoints. Default sampling: temperature=1.0, top_p=0.95.

    Python
    from openai import OpenAI
    
    client = OpenAI(
        api_key="your-api-key-here",
        base_url="https://api.doubleword.ai/v1"
    )
    
    # Long-horizon agentic coding task
    response = client.chat.completions.create(
        model="zai-org/GLM-5.3",
        messages=[
            {"role": "user", "content": "Audit this repository for unsafe deserialization and open a patch plan."}
        ],
        temperature=1.0,
        top_p=0.95,
    )
    
    print(response.choices[0].message.content)

    💡 Pro Tip

    Route long-running agent steps through the async tier and bulk evals through batch — same model, same API, at half the realtime rate. See the docs for the batch job format.