GPT-5.2 API
GPT-5.2 by OpenAI is a powerful LLM supporting text and image input/output, enhanced reasoning, and up to 400,000 tokens context for complex tasks.
GPT-5.2 API - Background
Overview
GPT-5.2 is OpenAI's latest large language model, released in December 2025, offering advanced natural language understanding, long-context processing, and powerful multimodal capabilities. Designed to improve reasoning, coding, and reliability, GPT-5.2 is accessible via the GPT-5.2 API for a wide range of professional and enterprise applications, supporting both text and image input/output.
Development History
GPT-5.2 was announced and made available on December 11, 2025, building upon the advances of the GPT-5 series. The model introduced significant upgrades in context window size, reasoning abilities, and multimodal functionality. Following its release, legacy models such as GPT-5.1 are scheduled for gradual phase-out, while business, enterprise, and developer users are encouraged to migrate to the enhanced GPT-5.2 API.
Key Innovations
- Support for up to 400,000 input tokens enabling efficient long-context comprehension
- State-of-the-art multimodal capabilities allowing both text and image input/output
- Substantial reduction in hallucination rates, increasing model reliability by approximately 30% over previous versions
GPT-5.2 API - Technical Specifications
Architecture
GPT-5.2 is part of the Generative Pre-trained Transformer 5 series, featuring transformer-based architecture optimized for complex reasoning, long-context understanding, and multimodal tasks. Three primary API model variants are available: Instant for speed, Thinking for constrained deep reasoning, and Pro for top-tier accuracy.
Parameters
OpenAI has not disclosed the exact number of parameters, but GPT-5.2 represents a scale and complexity significantly larger than its predecessors, tailored for high-demand professional AI workloads.
Capabilities
- Processes up to 400,000 input tokens per request for extended and complex documents
- Generates up to 128,000 output tokens per API call, suitable for lengthy reports or projects
- Delivers advanced text and image understanding through multimodal support
Limitations
- May still face challenges processing extremely specialized or niche professional content
- Currently does not support audio or video input/output modalities via the GPT-5.2 API
GPT-5.2 API - Performance
Strengths
- Outstanding performance in multilingual and long-context reasoning tasks
- Best-in-class coding and mathematics proficiency, evidenced by top scores in industry benchmarks
Real-world Effectiveness
In practical deployments, the GPT-5.2 API consistently demonstrates elevated reliability, reduced hallucination rates, and superior handling of long documents. For coding, it achieves a record 55.6% on the SWE-Bench Pro benchmark, and for mathematical reasoning, it scores 100% on the AIME 2025 competition without tools. These improvements translate to measurable business value for applications requiring precision, scalability, and contextual retention.
GPT-5.2 API - When to Use
Scenarios
- You have a need to generate comprehensive reports or analyze complex, lengthy documents. The GPT-5.2 API excels at managing up to 400,000 input tokens, making it ideal for legal reviews, research synthesis, or compliance audits. This enables efficient handling of otherwise time-consuming manual work, reducing turnaround time and improving accuracy for enterprise workflows.
- You are tackling code generation, refactoring, or technical documentation tasks. With its advanced reasoning and top-tier coding abilities, the GPT-5.2 API (especially the Thinking and Pro variants) allows for reliable automation of challenging software engineering chores. This not only boosts productivity for developer teams but also minimizes code errors, as validated by its SWE-Bench Pro benchmark scores.
- You run business-critical operations requiring reliable language model outputs integrated into customer-facing platforms. The enhanced reliability and low hallucination rate of the GPT-5.2 API ensure trustworthy answers and smooth user experiences, which is vital for sectors such as healthcare, finance, or customer service, where precision is non-negotiable.
Best Practices
- Choose the GPT-5.2 API variant that fits your workload—use Instant for high-throughput tasks, Thinking for deep reasoning, and Pro for maximum accuracy.
- Leverage the multimodal input/output features of the GPT-5.2 API to optimize applications that combine text and image analysis.