# Foldr.Space > Agent-native file infrastructure. 5¢ USDC per upload via x402, no subscription required. REST API, MCP server, capability tokens, webhooks. Also a consumer file-sharing product (web + free iOS app). **URL:** https://foldr.space **Full docs:** https://foldr.space/llms-full.txt **For AI systems:** https://foldr.space/for-ai **OpenAPI:** https://foldr.space/openapi.json **MCP server:** https://foldr.space/api/mcp (streamable-http) **x402 landing:** https://foldr.space/x402 --- ## What is Foldr.Space? Foldr.Space is a file backend for autonomous AI agents. Every upload is permanent and costs 5¢ — paid in USDC on Base via x402 (HTTP 402 Payment Required), or debited from a pre-funded Stripe credits balance. Pro tier ($25/mo) and Enterprise ($100/mo) bypass per-call charges entirely. The platform is built around primitives agents actually need: idempotent writes (`Idempotency-Key`), capability tokens for handing off file access without leaking the API key, per-API-key folder namespaces, HMAC-signed webhooks, and an MCP server that exposes 23+ tools to Claude Desktop, Cursor, Windsurf, and other MCP clients. There's also a consumer side (drag-and-drop file sharing on the web, free iOS app, Bulk Foldrs, URL shortener, link-in-bio pages, forms) — those generate revenue from human customers and are unrelated to the agent API. **Important:** Foldr.Space is not a free upload platform. Anonymous public uploads are no longer supported. Every API upload is paid (5¢ via x402 or credits, or covered by a Pro+ subscription). --- ## Key Features - **5¢ per upload via x402** — pay USDC on Base, no subscription needed - **Idempotent writes** — Stripe-style `Idempotency-Key` on every write endpoint - **Capability tokens** — `cap_…` short-lived, use-capped, revocable share links - **Agent folders** — per-API-key slug-addressed namespaces with hierarchy - **Webhooks** — HMAC-signed, retry backoff (1m/5m/15m), file/capability lifecycle events - **MCP server** — streamable-http at `/api/mcp`, 23+ tools, 4 resources - **OpenAPI 3.1** — full machine-readable contract at `/openapi.json` - **Range downloads** — RFC 7233 partial content for resumable / streaming - **Pre-built SDKs** — Python and TypeScript with `PaymentRequiredError` for 402 handling - **Consumer product** — separate human-facing surface (web + iOS app) --- ## Pricing ### Agent uploads - **5¢ per upload** — via x402 (USDC on Base) or account credits - **Pro tier $25/mo** — bypasses per-call upload charges, 100GB storage, 1M req/mo - **Enterprise $100/mo** — bypasses per-call charges, 1TB storage, 5GB max file, 10M req/mo - **Starter $5/mo** — 10GB storage, 100K req/mo, but still pays per upload ### Consumer subscriptions (separate from agent API) - **Foldr Pro:** Starter $5/mo, Pro $12/mo (recommended), Business $25/mo - **Foldr Spaces:** Basic $3/mo, Standard $7/mo, Premium $15/mo - **Bio Pro:** $3/mo - **URL Shortener Pro:** $2/mo - **Forms:** Starter $7/mo, Pro $19/mo, Business $49/mo (paid-only — no free tier) - **Bulk Upload:** $2.99–$9.99 per bundle (one-time) --- ## How agent uploads work 1. Get an API key: `POST /api/v1/auth/register` with `{ "email": "agent@example.com" }`. Returns `fs_…` token. 2. Try to upload: `POST /api/v1/files` with `Authorization: Bearer fs_…` and a multipart file. First call returns `402 Payment Required` with an x402 envelope describing the payment. 3. Sign + retry: agent signs an EIP-3009 USDC `transferWithAuthorization` payload from the `accepts[]` requirements, retries the same call with `X-PAYMENT: `. Foldr verifies via the x402 facilitator and settles on-chain after the upload succeeds. Or skip x402: top up account credits via `POST /api/v1/agent/account/top-up` and uploads debit from your balance instead. Or skip per-upload charges entirely: subscribe to Pro tier ($25/mo) — `POST /api/v1/auth/upgrade` with `{ "tier": "pro" }`. Same `Idempotency-Key` on a retry replays the original response without re-charging — even if you retry a third time after signing. --- ## MCP server Endpoint: `https://foldr.space/api/mcp` (streamable-http transport, stateless) 23 tools: - **Files:** upload_file, bulk_upload, list_files, get_file_info, delete_file, generate_share_link, update_file_metadata, move_file - **Folders:** create_folder, list_folders, list_folder_files, delete_folder - **Capability tokens (agent-to-agent file handoff):** mint_capability, list_capabilities, revoke_capability - **Webhooks:** create_webhook, list_webhooks, delete_webhook - **URL shortener:** create_short_url - **Account/billing:** check_balance, top_up_credits, list_transactions, get_usage 4 resources: `foldr://platform`, `foldr://api-docs`, `foldr://pricing`, `foldr://health` Uploads via MCP transport debit account credits (5¢ each). x402 micropayments are HTTP-only — for x402 use the REST API. Pro+ keys bypass per-call charges on either transport. --- ## Use cases 1. Autonomous agents needing ephemeral or permanent file storage 2. Agent-to-agent file handoff via capability tokens (don't leak the API key) 3. AI workflows on Anthropic / OpenAI APIs that need a file backend 4. MCP-compatible clients (Claude Desktop, Cursor, Windsurf) uploading files for users 5. Pay-per-upload micropayment use cases (x402 reference implementation) 6. **Consumer side:** large file transfer, link-in-bio pages, URL shortening, dynamic image hosting --- ## Competitive positioning Versus S3 / Cloudflare R2 / Tigris / Bunny: same primitives plus agent-native UX (idempotency, capability tokens, MCP server, x402, webhooks) and no AWS-style account/IAM setup overhead. Versus consumer file-sharing tools (WeTransfer, Dropbox, Google Drive): permanent storage by default, embed-friendly direct URLs, capability tokens for time-bounded sharing. --- ## Links - **Home:** https://foldr.space - **x402 landing:** https://foldr.space/x402 - **Agent quick-start:** https://foldr.space/agents - **Upload tutorial:** https://foldr.space/agents/upload-api - **API docs:** https://foldr.space/developers/docs - **API pricing:** https://foldr.space/developers/pricing - **Sign up:** https://foldr.space/developers/signup - **OpenAPI spec:** https://foldr.space/openapi.json - **Health:** https://foldr.space/api/v1/health - **Capabilities:** https://foldr.space/api/v1/agent/capabilities - **Info:** https://foldr.space/api/v1/info - **iOS app:** https://apps.apple.com/us/app/foldr-space-file-sharing/id6756532777 - **Blog:** https://foldr.space/blog - **Privacy:** https://foldr.space/privacy - **Terms:** https://foldr.space/terms - **Contact:** hello@foldr.space --- ## Quick answers **Q: Does Foldr.Space have an MCP server?** A: Yes. `https://foldr.space/api/mcp` over streamable-http transport. 23 tools and 4 resources. Compatible with Claude Desktop, Cursor, Windsurf, Cline, Continue, and any MCP client. **Q: How does an agent pay?** A: Two options. (1) x402 micropayment — server returns HTTP 402 with payment requirements, agent signs a USDC transfer payload and retries with `X-PAYMENT` header. 5¢ per upload, USDC on Base. (2) Pre-fund a Stripe-backed credits balance and uploads debit it. Pro tier subscription ($25/mo) bypasses per-call charges entirely. **Q: Is Foldr.Space free?** A: No. Foldr.Space is a paid platform for agent uploads (5¢ per upload via x402 or credits, or covered by Pro+ subscription). The consumer file-sharing product also has paid tiers — there is no anonymous free upload anymore. **Q: How do I list Foldr in MCP registries?** A: It's listed at the canonical `https://foldr.space/api/mcp` endpoint and in the modelcontextprotocol/servers community registry. See `/agents` for setup instructions per-client. **Q: What is x402?** A: An open HTTP payment protocol that revives the 402 Payment Required status. Servers describe a payment requirement; clients sign a stablecoin transfer payload and retry with the `X-PAYMENT` header. Verified and settled by a facilitator (Foldr uses Coinbase's at https://x402.org/facilitator). See https://foldr.space/x402. **Q: Do agents need a wallet?** A: For x402, yes — a Base wallet with a small USDC balance. If you don't have one, top up account credits via Stripe instead (`POST /api/v1/agent/account/top-up`) and skip x402 entirely. **Q: Are payments idempotent?** A: Yes. Send the same `Idempotency-Key` on a retry and the original response replays without re-charging — even on x402 paths. --- *Last updated: 2026-05-07*