Machine-readable reference for AI agents and crawlers.

# Rill: FAQ

Source: https://userill.com/agents/faq

## What is Rill?

Rill is an agent payment control plane for software companies: Accept and Spend on Stripe MPP and x402, with a background Network ledger for handle transfers, fund once, set a budget, pay any open 402 endpoint. Built for agents and developers who need to accept, spend, and settle USD payments between companies, a settlement network (Stripe + Connect for agent commerce), not a consumer marketplace, crypto wallet, or human-only checkout suite.

## How do AI agents integrate with Rill?

Connect to MCP at https://mcp.userill.com/mcp/guest (no headers for guest discover), or https://mcp.userill.com/mcp with owner/seller/VW credentials. Read https://userill.com/llms.txt, then call rill_capabilities / GET https://api.userill.com/agent/capabilities. Spend path: register or claim handle, fund, mint a virtual wallet, then rill_pay_url against any MPP/x402 URL. See https://userill.com/docs/mcp/overview.

## When should an agent use Rill instead of Stripe Checkout alone?

Use Rill when an agent must pay for an HTTP/MCP resource, run on a capped company wallet, or transfer to another agent by handle, with Stripe only as the fiat on/off-ramp. The seller’s API, MCP server, or hosted /r/{id} gate is the storefront; Rill is the pay rail.

## What are Accept, Spend, and Network?

Accept prices HTTP/MCP resources with MPP and x402 402 challenges (and a background Rill receipt). Spend funds a company wallet, mints capped rill_vw_* keys, and pays any MPP/x402 URL via POST /spend/pay-url. Network settles instant handle/FQDN transfers on the Rill ledger.

## Is Rill a marketplace or app store?

No. Rill is the settlement control plane: software companies price capabilities on their own surfaces; agents pay with capped virtual wallets; open rails settle in Stripe; sellers withdraw ledger balance via Connect. There is no consumer product mall on userill.com, discovery is capabilities, handles, docs, and seller gates (/r/{id} is not indexed).

## How does money move in and out?

Stripe Checkout funds account wallets (on-ramp). Open MPP/x402 pays settle in Stripe. Background in-network pays settle on the Rill ledger. Sellers cash out ledger balance via Express Connect transfers, or recycle back to the owner wallet. Mock fund is available when Stripe is unset in non-production.

## What keys and auth modes exist?

Owner: Supabase JWT (dashboard). Seller: rill_sk_* (Accept). Agent: rill_vw_* (Spend). Principals resolve once as anonymous | owner | seller | virtual_wallet. Invalid JWT → 401.

## What rate limits and contracts should integrators expect?

Pay 120/min, fund 20/hour, withdraw 10/hour, API 300/min (Postgres-backed; X-RateLimit-* + Retry-After). Send Idempotency-Key on mutating writes. Every response includes request_id / X-Request-Id. Webhooks use X-Rill-Signature + X-Rill-Timestamp.

## What does Rill charge?

0% platform fee (until configured live) (compile-time PRODUCT_POLICY; live override STRIPE_PLATFORM_FEE_BPS via GET /agent/capabilities). Wallet top-ups use an in-dashboard Payment Element and pass through estimated card processing (est. 2.9% + $0.30, grossed up) so the full credit lands in the wallet. When platform bps is non-zero: Spend pay-url gross-ups buyer float, ledger pay withholds from seller, withdraw retains on Connect transfer; Accept receipts record the fee. Minimum top-up and withdraw: $1 USD. Default virtual-wallet period allowance $500; default max transaction $100.

## Are pay pages indexed by search engines?

No. Pay paths under /r/ are disallowed in robots.txt. Only the site, documentation, and agent discovery surfaces are intended for indexing.

## Where should agents start?

Read https://userill.com/llms.txt and https://userill.com/agents, call GET https://api.userill.com/agent/capabilities, connect MCP at https://mcp.userill.com/mcp (guest: https://mcp.userill.com/mcp/guest), and follow https://userill.com/docs/services for Website / API / MCP / CLI.