GPT-5.5 Instant

Tool callingStructured outputReasoningImage inputFile input

Launch post Website

Compact GPT model for low-latency assistance and high-volume workloads

Context: 400K
Released: 5mo ago

Sources:models.dev

Benchmarks

DeepSWE is the primary coding benchmark where an exact model evaluation exists. Other sourced evaluations appear below; missing scores are not zero.

Not evaluated in DeepSWE 1.1 as of 2026-09-22. Results are only shown for exact model versions in the official dataset. Official leaderboard.

Other published benchmarks

Evaluation	Reported score and source
FrontierMath-Tier-4-v2-Private	2.4% Epoch AI · gpt-5.5-instant Epoch AI evaluation
FrontierMath-Tiers-1-3-v2-Private	26.3% Epoch AI · gpt-5.5-instant Epoch AI evaluation
GPQA diamond	82.5% Epoch AI · gpt-5.5-instant Epoch AI evaluation
OTIS Mock AIME 2024-2025	68.1% Epoch AI · gpt-5.5-instant Epoch AI evaluation

Benchmark compilation: Epoch AI, Capabilities & benchmarking (CC BY attribution). Scores are converted to percentages and model names matched to the Vertical Tabs catalog. Individual evaluations are credited to their original sources. External results may carry separate licences and evaluation configurations; do not interpret scores from different harnesses as directly comparable.

Specifications

Developer: OpenAI
Model family: GPT
Type: Language model
Predecessor: —
Successor: —
Released: May 5, 2026
Model ID: openai/gpt-5.5-instant
Openness: Closed
License: —
Input modalities: text, image, file
Output modalities: text
Modality: text+image+file->text
Max output tokens: 128K
Knowledge cutoff: 2025-12-01
Hugging Face: —
Source freshness: Metadata synced Oct 8, 2026, 10:17 PM UTC

Additional source evidence

Source model: openai/gpt-5.5-instant
Last updated: 2026-05-28
Knowledge cutoff: 2025-12-01
Model context: 400K
Maximum input: 272K
Model output limit: 128K
Open weights: No
File attachments: Yes
Reasoning: Yes
Tool calling: Yes
Structured output: Yes
Temperature control: Yes

Complete source record (JSON)

{
  "id": "openai/gpt-5.5-instant",
  "name": "GPT-5.5 Instant",
  "description": "Compact GPT model for low-latency assistance and high-volume workloads",
  "last_updated": "2026-05-28",
  "knowledge": "2025-12-01",
  "attachment": true,
  "reasoning": true,
  "tool_call": true,
  "structured_output": true,
  "temperature": true,
  "modalities": {
    "input": [
      "text",
      "image",
      "pdf"
    ],
    "output": [
      "text"
    ]
  },
  "limit": {
    "context": 400000,
    "input": 272000,
    "output": 128000
  },
  "release_date": "2026-05-05",
  "open_weights": false
}

Infrastructure

Provider availability

All providers

Provider endpoint data will appear after this model's first OpenRouter endpoint sync.

Text provenance

EU · product-scoped

OpenAI textGrain watermarking

In the EU, ChatGPT-generated text uses textGrain. OpenAI says API customers can opt in globally for select models, so watermarking depends on the product surface and configuration.

Official explanation