SYSTEM Cited by 7 sources

Cloudflare R2

R2 is Cloudflare's object-storage tier on the Developer Platform — S3-compatible, with zero egress fees, a generous free tier, and first-class integration with Workers and Sandbox SDK.

Filesystem-mount integration

From Sandbox SDK, sandbox.mountBucket() presents an R2 bucket as a filesystem partition inside a Cloudflare Container. This is the platform's standard answer to the problem that Containers are ephemeral by design (concepts/container-ephemerality) — application code sees a local directory that survives container replacement, with zero application changes (patterns/mountable-persistent-storage).

Seen in

• sources/2026-01-29-cloudflare-moltworker-self-hosted-ai-agent — canonical wiki instance. Moltworker mounts an R2 bucket into the Moltbot Sandbox container to host session memory files, conversations, and other agent state that needs to outlive the container lifecycle.
• sources/2026-04-15-cloudflare-project-think-building-the-next-generation-of-ai-agents — R2 pairs with DO SQLite as the Tier 0 substrate of Project Think's execution ladder — the "durable virtual filesystem" an agent sees as its workspace: read, write, edit, search, grep, diff. Powered by @cloudflare/shell. Tier 0 is the "useful at the bottom" rung — the agent is useful with just the workspace, and every higher tier shares its state with Tier 0.
• sources/2026-04-16-cloudflare-ai-search-the-search-primitive-for-your-agents — R2 as managed storage substrate inside every AI Search instance. "Each instance gets its own built-in storage and vector index — powered by R2 and Vectorize." An R2 bucket can also be attached as an external data source on an AI Search instance (sync-on-schedule), which is how the canonical support-agent example backs the shared product-knowledge instance with a customer's product-docs bucket. Same primitive used two ways: bundled-and-invisible (built-in storage) + customer-facing-and-crawled (external source).
• sources/2026-04-16-cloudflare-artifacts-versioned-storage-that-speaks-git — R2 as the pack-file snapshot store behind every Artifacts repo. Each repo's hot Git objects live in its Durable Object's embedded SQLite (chunked across rows — 2 MB row limit); R2 holds durable pack-file snapshots for longer-tail blob storage and efficient multi-GB retrieval. Third substrate role on R2 (Tier 0 workspace for Project Think → managed-storage for AI Search instances → pack-file snapshots for Artifacts repos). Part of patterns/do-backed-git-server.
• sources/2026-04-16-cloudflare-email-service-public-beta-ready-for-agents — R2 as the attachment store for Agentic Inbox. The open-source reference app stitches Email Routing + Email Sending + Workers AI classification + R2 attachments + Agents SDK. Fourth substrate role on R2 (Tier 0 workspace → AI Search managed-storage → Artifacts pack-files → email attachments).
• sources/2026-05-28-cloudflare-how-we-built-cloudflares-data-platform-and-an-ai-agent-on-top-of-it — R2 is the cold/warm storage tier of Town Lake, Cloudflare's unified data platform. R2 Data Catalog — Cloudflare's managed Apache Iceberg service — sits on top of R2 to provide schema evolution, time travel, partition evolution, and recency-tiered recompaction (per-minute usage from last week → hourly from last quarter → daily beyond). Parquet files in R2 are "much cheaper compared to keeping the same data in an OLAP database." Fifth substrate role on R2 (Tier 0 workspace → AI Search managed-storage → Artifacts pack-files → email attachments → managed-Iceberg-catalog tier for Town Lake). The pattern — "single primitive (R2) wrapped in domain-specific managed services" — is now the explicit Cloudflare-Developer-Platform-coherence shape.

Related

• systems/cloudflare-sandbox-sdk — the interface that mounts R2 into containers.
• systems/cloudflare-containers — the ephemeral-by-design compute tier R2 complements.
• systems/cloudflare-workers — the native object-store client tier.
• patterns/mountable-persistent-storage — the pattern R2 + Sandbox SDK realise together.
• concepts/container-ephemerality — the problem shape.
• systems/cloudflare-artifacts — uses R2 as the pack-file snapshot store behind each per-repo DO.
• patterns/do-backed-git-server — the Artifacts substrate pattern.
• systems/cloudflare-r2-data-catalog — Cloudflare's managed Iceberg service on top of R2; the cold/warm tier of Town Lake.
• systems/cloudflare-town-lake — the data platform that consumes R2 as its lakehouse storage substrate.
• companies/cloudflare — operator.

Local-dev parity

R2 is one of the binding types exposed through the Local Explorer local mirror of the Cloudflare API at /cdn-cgi/explorer/api, backed by Miniflare's on-disk object store. Same API shape local and remote — differs only by the --local flag on cf / Wrangler (Source: sources/2026-04-13-cloudflare-building-a-cli-for-all-of-cloudflare).