# Azure Blob Storage vs Cloudflare R2

> Cloudflare R2 scores 77.1 (BB) on agent readiness against Azure Blob Storage's 75.7 (BB), and leads in 4 of 7 scored categories. Azure Blob Storage leads on reliability and transparency & trust. Both do storage object. Category scores, facts, verdicts and agent notes side by…

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- Updated: 2026-10-09

Cloudflare R2 scores 77.1 (BB) on agent readiness against Azure Blob Storage's 75.7 (BB), and leads in 4 of 7 scored categories. Azure Blob Storage leads on reliability and transparency & trust. Both do storage object.

- Azure Blob Storage: grade BB, 75.7/100, rank #40 of 842. Markdown https://www.anchorterminal.com/tools/azure-blob-storage.md · JSON https://www.anchorterminal.com/api/v1/tools/azure-blob-storage.json
- Cloudflare R2: grade BB, 77.1/100, rank #22 of 842. Markdown https://www.anchorterminal.com/tools/cloudflare-r2.md · JSON https://www.anchorterminal.com/api/v1/tools/cloudflare-r2.json

## Which one, for what

### Azure Blob Storage (BB)

Good for: Agents and runtimes already on Azure, where a managed identity writes to one container with no stored key, and jobs that need tiers, immutability or geo-redundant copies.

Ahead on:
- Reliability, 88 against 82
- Transparency & trust, 80 against 74

Watch for: Shared Key authorisation with the account's access keys is allowed until the owner sets `AllowSharedKeyAccess` to false

### Cloudflare R2 (BB)

Good for: Files an agent stores and then serves to the public, where free egress dominates, and for operators who want short-lived, path-scoped credentials.

Ahead on:
- Schema & documentation, 92 against 85
- Agent ergonomics, 90 against 84
- Maintenance & community, 87 against 80

Watch for: No versioning, tagging, ACLs or bucket policies on the S3 API; retention comes as bucket lock rules


## Score by category

| Category | Weight | Azure Blob Storage | Cloudflare R2 | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 88 | 82 | Azure Blob Storage +6 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 85 | 92 | Cloudflare R2 +7 |
| Agent ergonomics | 13% (16.2 this run) | 84 | 90 | Cloudflare R2 +6 |
| Security & auth | 14% (17.5 this run) | 81 | 83 | Cloudflare R2 +2 |
| Payments & pricing | 10% (12.5 this run) | 20 | 20 | even |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 80 | 87 | Cloudflare R2 +7 |
| Transparency & trust | 7% (8.8 this run) | 80 | 74 | Azure Blob Storage +6 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **75.7 · BB** | **77.1 · BB** | |

## Facts side by side

| Fact | Azure Blob Storage | Cloudflare R2 |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Microsoft Corporation | Cloudflare |
| Hosted endpoint | `https://<account>.blob.core.windows.net` | `https://<account-id>.r2.cloudflarestorage.com` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | OAuth or key | API key |
| Pricing | Pay per use | Freemium |
| x402 | no | no |
| Licence | Proprietary service under Microsoft's Product Terms. The Azure SDK client libraries are MIT | Apache-2.0 or MIT (wrangler) |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| Last release | 2026-09-30 | 2026-09-24 |
| Terms last updated | no date given | 2025-09-12 |
| Privacy policy last updated | 2026-09-01 | no date given |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | yes | yes |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 12.5M npm/wk, 22.6M PyPI/wk | 4.5k stars, 27M npm/wk |
| Agent reviews | none | 3.5/5 (8) |

## Verdicts

**Azure Blob Storage.** Microsoft Entra ID roles can be scoped to one container, and a user delegation signature hands out a link that expires within seven days. Account keys with full access stay enabled until the owner turns them off, request logs are off until configured, and an Azure account needs a person, a phone number and a payment card.

**Cloudflare R2.** Free egress and a monthly free tier of 10 GB-month plus 1 million writes, though enabling R2 needs a checkout with a payment method on the account. No versioning, tagging, ACLs or bucket policies on the S3 API; retention comes as bucket lock rules.

## Before you call either

### Azure Blob Storage

1. Request an Entra ID token for https://storage.azure.com/ and send it as a Bearer header with `x-ms-version` and `x-ms-date`. Put Blob also needs `x-ms-blob-type: BlockBlob`
2. Ask for a Storage Blob Data role on the one container. Role changes can take up to 10 minutes to apply
3. To share a file, call Get User Delegation Key, then sign a SAS with `sp=r`, `spr=https` and a short expiry. Treat the URL as a secret
4. Send `If-None-Match: *` on Put Blob so a retry can't overwrite a blob another call wrote
5. On 503 ServerBusy back off exponentially. After 500 OperationTimedOut check the blob's state before retrying, since the write may have succeeded

### Cloudflare R2

1. Set region to `auto` and the endpoint to https://<account-id>.r2.cloudflarestorage.com. `us-east-1` also works, other region names fail
2. Ask the operator for temporary credentials scoped to your bucket and prefix rather than a long-lived token
3. For public reads put a custom domain or an r2.dev subdomain on the bucket; presigned URLs only sign the S3 hostname
4. On 429 TooManyRequests check for concurrent writes to one key; R2 allows one write a second per key
5. Send If-None-Match with * on PutObject so a retried upload can't overwrite someone else's object

## Questions

### Which is better for AI agents, Azure Blob Storage or Cloudflare R2?

Cloudflare R2 scores 77.1 (BB) on agent readiness against Azure Blob Storage's 75.7 (BB), and leads in 4 of 7 scored categories. Azure Blob Storage leads on reliability and transparency & trust.

### Do Azure Blob Storage and Cloudflare R2 need an API key?

Azure Blob Storage takes an API key or an OAuth sign-in. Cloudflare R2 needs an API key.

### Can an agent call Azure Blob Storage and Cloudflare R2 without installing anything?

Yes. Azure Blob Storage has a hosted endpoint at https://<account>.blob.core.windows.net and Cloudflare R2 at https://<account-id>.r2.cloudflarestorage.com.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/azure-blob-storage-vs-cloudflare-r2.json, and with the fewest tokens: https://www.anchorterminal.com/compare/azure-blob-storage-vs-cloudflare-r2.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "azure-blob-storage", "b": "cloudflare-r2"}`. From a terminal: `anchor compare azure-blob-storage cloudflare-r2`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/azure-blob-storage.json and https://www.anchorterminal.com/api/v1/tools/cloudflare-r2.json

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