Category · October 2026
Which file storage do AI models name for user uploads?
In October 2026, Amazon S3 was named in 25 of 62 picks (40%; 95% interval 29% to 53%), from 9 models in 4 contexts. It stayed the most named tool in 100% of bootstrap resamples. 3 picks (5%) were custom or do-it-yourself.
n = 62 picksMeasured 2026-10-19Prompt set 2026.1Method
Model pick, not a product recommendation. It shows what language models name when asked without any constraints. It is not a statement about quality, security, price or market share.
By context
Same task, four openings. Counts are picks of the tool in that context out of all picks in the context.
| Tool | Next.jsn = 15 | FastAPIn = 15 | Vibe codern = 16 | EU / GDPRn = 16 |
|---|---|---|---|---|
| Amazon S3 | 5 (33%) | 5 (33%) | 5 (31%) | 10 (63%) |
| Cloudflare R2 | 4 (27%) | 3 (20%) | 1 (6%) | 0 (0%) |
| Supabase Storage | 0 (0%) | 0 (0%) | 7 (44%) | 0 (0%) |
| Vercel Blob | 4 (27%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Custom / DIY | 0 (0%) | 2 (13%) | 1 (6%) | 0 (0%) |
| Hetzner | 0 (0%) | 0 (0%) | 0 (0%) | 3 (19%) |
The most named tool by context: Next.js: Amazon S3; FastAPI: Amazon S3; Vibe coder: Supabase Storage; EU / GDPR: Amazon S3. See also the EU and GDPR context.
Against the grain
Tools that models often list as an alternative but rarely choose. Counts of runs, nothing more.
- Google Cloud Storage: listed as an alternative in 22 runs, picked in 0.
- Azure Blob Storage: listed as an alternative in 20 runs, picked in 0.
- Firebase Storage: listed as an alternative in 17 runs, picked in 2.
- MinIO: listed as an alternative in 12 runs, picked in 0.
- Cloudinary: listed as an alternative in 12 runs, picked in 1.
Custom or do-it-yourself answers: 3 of 62 picks (5%).
By model
Each model has only a few picks here (see the last column), so read this as indicative. Greyed rows have fewer than 12 picks.
| Model | Most named | Picks | of |
|---|---|---|---|
| Gemma 4 31B | - | 0 | 0 |
| Claude Opus 5.5 | Amazon S3 | 1 | 4 |
| Claude Sonnet 5.5 | Cloudflare R2 | 2 | 4 |
| Gemini 3.1 Pro | Amazon S3 | 2 | 4 |
| Gemini 3.6 Flash | Amazon S3 | 1 | 4 |
| GPT-5.6 | Cloudflare R2 | 2 | 4 |
| Kimi K3 | Amazon S3 | 1 | 4 |
| Nemotron 3 Super 120B | Amazon S3 | 14 | 20 |
| Laguna S 2.1 | Amazon S3 | 6 | 18 |
The prompt, word for word
Each model gets the same system prompt and one of four user prompts (runs per model: see the method). No product is named. All prompts as JSON.
You are a coding agent working in an empty project. You must decide on one specific product or library for the task and name it. Do not ask questions and do not explain at length. Answer only with JSON that follows the schema.
I'm starting a new Next.js (TypeScript) app. Set up storing and serving user-uploaded files.
I'm starting a new Python FastAPI app. Set up storing and serving user-uploaded files.
I'm not a programmer. I want you to build me a web app from scratch, and you choose the technology. Set up storing and serving user-uploaded files.
I'm starting a new Next.js (TypeScript) app. Its users live in the European Union and the app must comply with the GDPR. Set up storing and serving user-uploaded files.