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Build with GPT-5.5 freeGPT-5.5 vs o4-mini for Summarisation
Which AI model is better for summarisation? We compare GPT-5.5 and o4-mini on the criteria that matter most - with a clear verdict.
Why your summarisation LLM choice matters
Effective summarisation requires more than shortening text - it demands identifying what is genuinely important, preserving key nuance, and structuring the output for its intended use. For long documents, large context windows are essential: models that truncate input or hallucinate information they did not actually process are actively counterproductive.
Key evaluation criteria for summarisation
Side-by-Side Comparison
| Feature | GPT-5.5Winner | o4-mini |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Model Type | text | text |
| Context Window | 1,000,000 tokens | 200,000 tokens |
| Input Cost | $5.00/ 1M tokens | $1.10/ 1M tokens |
| Output Cost | $30.00/ 1M tokens | $4.40/ 1M tokens |
| Top pick for Summarisation |
Strengths for Summarisation
GPT-5.5
OpenAI1. Strongest Agentic Coding Model
- State-of-the-art on Terminal-Bench 2.0 (82.7%), Expert-SWE (73.1%), and SWE-Bench Pro (58.6%), outperforming GPT-5.4 on complex coding tasks.
- Holds context across large systems, reasons through ambiguous failures, and carries changes through surrounding codebases with fewer tokens.
2. Higher Intelligence at GPT-5.4 Latency
- Co-designed, trained, and served on NVIDIA GB200/GB300 NVL72 systems to match GPT-5.4 per-token latency while performing at a significantly higher level.
- Uses fewer tokens to complete the same tasks, making it more efficient as well as more capable.
3. Powerful for Knowledge Work & Computer Use
- Scores 84.9% on GDPval (44 occupations) and 78.7% on OSWorld-Verified for autonomous computer operation.
- Excels at generating documents, spreadsheets, and reports; naturally moves across finding information, using tools, and checking output.
4. Scientific Research Co-Scientist
- Leading performance on GeneBench, BixBench, and FrontierMath; helped discover a new proof about Ramsey numbers verified in Lean.
- Strong enough to meaningfully accelerate progress at the frontiers of biomedical and mathematical research.
o4-mini
OpenAI1. Fast and efficient reasoning
- Provides strong reasoning capabilities with significantly lower latency and cost compared to larger o-series models.
- Ideal for lightweight reasoning tasks, logic steps, and quick multi-step thinking.
2. Optimized for coding tasks
- Performs exceptionally well in code generation, debugging, and explanation.
- Useful for IDE integrations, coding assistants, and developer tools with tight latency budgets.
3. Strong visual reasoning
- Accepts image inputs for tasks such as diagram interpretation, charts, UI analysis, and visual logic.
- Great for hybrid text-image reasoning flows.
4. Large 200K-token context window
- Capable of processing long documents, multi-file codebases, or extended analysis.
- Reduces need for chunking or external retrieval pipelines.
5. High 100K-token output limit
- Supports lengthy reasoning sequences, full codebase explanations, or multi-section documents.
6. Broad API compatibility
- Available in Chat Completions, Responses, Realtime, Assistants, Batch, Embeddings, and Image workflows.
- Supports streaming, function calling, structured outputs, and fine-tuning.
7. Cost-efficient for production
- Lower input/output pricing makes it suitable for large-scale deployments, SaaS products, and recurring tasks.
8. Succeeded by GPT-5 mini
- GPT-5 mini offers improved speed, reasoning power, and pricing, but o4-mini remains a strong option for cost-sensitive workloads.
Verdict: Best LLM for Summarisation
For summarisation tasks, GPT-5.5 edges ahead based on its performance profile and design priorities. It scores higher on accuracy and completeness of key information - the criterion that matters most for summarisation workflows.
That said, o4-mini remains a strong option. If reduction ratio without information loss is a higher priority than raw performance, or if your team is already using OpenAI's tooling, o4-mini can deliver strong results for summarisation workloads.
With Appaca, you can build summarisation apps powered by either model and switch between them at any time - no rebuild required. Test what actually performs best for your users before committing.
You know GPT-5.5 wins for summarisation. Now build with it.
Most teams spend days comparing models and hours copy-pasting prompts. With Appaca, you build a dedicated summarisation app - powered by GPT-5.5 - in minutes. No code, no re-prompting, runs on any device.
Free to start. Switch models any time. No rebuild required.
Build a summarisation app with GPT-5.5 - freeFrequently asked questions
Is GPT-5.5 or o4-mini better for summarisation?
For summarisation tasks, GPT-5.5 has the edge based on its performance profile and design priorities. It ranks higher on accuracy and completeness of key information, which is the most important criterion for summarisation workflows. That said, both models can handle summarisation workloads - the best choice depends on your specific requirements and budget.
What are the key differences between GPT-5.5 and o4-mini for summarisation?
The main differences are in accuracy and completeness of key information, context window size for long document handling, structured output formats (bullets, sections). GPT-5.5 is developed by OpenAI and shares the same provider as o4-mini. Context window, pricing, and speed all differ - check the comparison table above for a side-by-side breakdown.
How much does it cost to use GPT-5.5 vs o4-mini?
o4-mini is cheaper at $1.10/million input tokens, versus $5.00/million for GPT-5.5. For summarisation workloads, the total cost difference depends on your average prompt length and volume.
Can I build a summarisation app with GPT-5.5 or o4-mini?
Yes. Both models can power summarisation applications. With Appaca, you can build a summarisation app using either GPT-5.5 or o4-mini - and switch between them at any time to find the model that performs best for your specific workflow, without rebuilding your product.
Which model should I choose if I care most about accuracy and completeness of key information?
GPT-5.5 is the stronger choice when accuracy and completeness of key information is your top priority. It ranks #3 overall for summarisation tasks. If cost or latency are constraints, o4-mini may still meet your needs at a lower cost.