GPT-5.5 Pro
April 2026 professional reasoning summit, combining 1-million-token context with 89.5% SWE-bench Verified and 93.8% GPQA Diamond scores.
1,000k
~750k words input
$10 / $40
Prompt / Completion per 1M
89.5 % resolved
SWE-bench Verified
Cloud Managed
Zero local VRAM
Holistic Capability Distribution
Normalized 0-100 rating vectors balanced across intelligence, throughput, and economics.
Verified LLM Benchmarks
Empirical evaluations across academic reasoning, software engineering, agentic execution, and human preference.
Inference Latency & Generation Throughput
Empirical telemetry benchmarking generation throughput (Tokens/Second) and Time to First Token (TTFT).
Measured under concurrent production load
p95 latency: 1180 ms
Across 2,900 monitored requests
Architectural Strengths vs. Operational Considerations
An objective technical balance sheet analyzing deployment advantages and production constraints.
Key Architectural Strengths
- Unrivaled 89.5% SWE-bench Verified and 93.8% GPQA Diamond precision.
- Massive 128,000 max output token budget for end-to-end system generation.
- Full 1M token context window.
Operational Considerations
- Higher compute latency on deeply branching test-time proof paths.
Hardware & Execution Parameters
Genealogical Provenance
Apex reasoning milestone of the GPT-5.5 release.
openai gpt 5 4 pro
GPT-5.5 Pro
Architecture Engineering & Capability Deep-Dive
Topology & Attention Mechanics
Unified reasoning architecture with multi-agent internal verification routines over 1M context.
Evaluation Profile & Reasoning Capabilities
Formal software specification synthesis, multi-theorem mathematical proof discovery.
Inference Economics & Cost Optimization
$10 / $40 per 1M tokens.
Primary Production Workloads & Suitability
Cloud Deployment Architecture & Hardware Sizing
Cloud Deployment Architecture
Distributed enterprise serving infrastructure, autoscaling semantics, and runtime execution profile.
Proprietary commercial model hosted on managed multi-region clusters with automatic autoscaling, high availability, and prompt prefix caching.
Multi-Tenant Cloud API
Continuous autoscaling with regional failover
0 GB Local VRAM
Inference executed on hyperscaler accelerator clusters
1,000k tokens
Supported with automated KV cache prefix compression
SDK Installation
Official Repositories & Papers
Compare Showdowns
GPT-5.5 Pro vs Claude Opus 4.8
Compare GPT-5.5 Pro against Claude Opus 4.8's verified benchmarks, context window, and pricing.
GPT-5.5 Pro vs GPT-5.5
Compare GPT-5.5 Pro against GPT-5.5's verified benchmarks, context window, and pricing.
GPT-5.5 Pro vs OpenAI Decisions
Compare GPT-5.5 Pro against OpenAI Decisions's verified benchmarks, context window, and pricing.
GPT-5.5 Pro vs GPT-3.5 Turbo
Compare GPT-5.5 Pro against GPT-3.5 Turbo's verified benchmarks, context window, and pricing.
Commercial Token Rates & Cost Estimator
$10.00 / 1M
Standard prompt context ingestion
$40.00 / 1M
Generated completion & thinking tokens
$1.00 / 1M
Re-used prompt prefix context
Monthly Production Cost Simulator
$2,160.00
Includes prompt caching
-$540.00
Saved via prefix context caching
Comparable Foundation Architectures
Alternative foundation models with comparable intelligence benchmarks, context windows, and deployment profiles.
Claude Opus 4.8
The peak culmination of Anthropic's Claude 4 architecture, featuring half-million-token context, 87.5% SWE-bench Verified, and lowered flagship pricing ($10/$50).
GPT-5.5
April 2026 breakthrough expanding context to 1-million tokens natively while achieving 86.5% on SWE-bench Verified at affordable $3/$12 economics.
OpenAI Decisions
OpenAI Decisions is OpenAI's dedicated high-throughput decision-making API powered by GPT-6 Luna, accessed via the POST /v1/decisions endpoint. Designed for agent routing, automated content moderation, and classification, it processes typed questions (predicates, categorical choices, and rubric scores) roughly 10x faster than standard generation, billed at $0.10 per million input tokens with zero output-token fees.
GPT-3.5 Turbo
OpenAI's foundational conversational model that launched the ChatGPT era, optimized for fast dialogue, summary generation, and lightweight JSON tasks.
SDK Installation & API Integration
import OpenAI from 'openai';
const client = new OpenAI();
const completion = await client.chat.completions.create({
model: 'gpt-5.5-pro',
messages: [{ role: 'user', content: 'Design a distributed fault-tolerant database architecture from first principles.' }],
});
console.log(completion.choices[0].message.content);Frequently Asked Questions about GPT-5.5 Pro
Engineering specifications, VRAM sizing, commercial licensing terms, token economics, and empirical benchmark evaluations.
GPT-5.5 Pro supports up to 128,000 output tokens in a single completion.