# FlexYield

> One API key and one bill for multi-chain JSON-RPC access, with automatic multi-provider failover — at prices below going direct. No wallet, no crypto required.

FlexYield is a unified RPC gateway: point your application at a single endpoint and every JSON-RPC 2.0 request is routed to the best healthy upstream provider, with automatic failover and per-key usage metering. Accounts are email-based, plans are card-billed, and a live dashboard shows volume, latency, and spend per API key.

## Getting started

1. Sign up (free tier included): https://flexyield.io/registration/new
2. Create an API key in the dashboard — the plaintext token is shown exactly once.
3. Relay JSON-RPC requests:

    curl -X POST https://flexyield.io/rpc/eth_mainnet \
      -H "Authorization: Bearer YOUR_API_KEY" \
      -H "Content-Type: application/json" \
      -d '{"jsonrpc":"2.0","id":1,"method":"eth_blockNumber"}'

## Supported chains

Relay to any of these with POST https://flexyield.io/rpc/{chain}:

- arbitrum_one — Arbitrum One
- base_mainnet — Base Mainnet
- eth_mainnet — Ethereum Mainnet
- optimism_mainnet — OP Mainnet
- polygon_pos — Polygon PoS
- solana_mainnet — Solana Mainnet

## Data API (beyond raw RPC)

Same bearer API key and metering as /rpc. Requires a paid plan (free-tier
keys receive error -32010). Status: premium data upstreams are
onboarding — these endpoints answer 503 until a data-capable provider is live.

- GET https://flexyield.io/data/{chain}/balances/{address} — native balance (all chains); ERC-20 token balances on chains with a data-capable upstream
- GET https://flexyield.io/data/{chain}/history/{address} — recent asset transfers, newest first (chains with a data-capable upstream)

## Pricing

- Free: free — 1,000,000 requests/month included · burst up to 100 requests per 15 minutes
- Builder: $12.00/month — Unlimited requests · fair-use burst up to 1,800 requests/min
- Pro: $99.00/month — 15,000,000 requests/month included · burst up to 3,000 requests/min
- Pro (yearly): $990.00/year — 15,000,000 requests/month included · burst up to 3,000 requests/min
- Enterprise: custom plans with dedicated capacity — hello@flexyield.io

Full pricing: https://flexyield.io/pricing

## MCP (for AI agents)

FlexYield exposes its capabilities as an MCP server at https://flexyield.io/mcp (HTTP+SSE transport). Public tools need no authentication; account tools authenticate with your API key as a bearer token in the Authorization header.

Tools:
- create_api_key: Create a new FlexYield API key for the authenticated account. Returns the plaintext token exactly once — store it securely, it cannot be retrieved again.
- revoke_api_key: Revoke one of the authenticated account's API keys. Requests using the key stop working immediately. Idempotent.
- usage_report: Report the authenticated account's RPC gateway usage: total requests, success rate, latency (avg + p95), per-key volume/latency/errors/last-used, and per-method and per-chain counts.
- list_plans: List FlexYield's public subscription plans: prices in integer USD cents, billing interval, monthly included request quota, and burst rate limits. No authentication required.
- join_waitlist: Join the FlexYield early-access waitlist. Qualifier must be one of: developer, investor, curious. No authentication required.
- get_balances: Native balance (all supported chains) and ERC-20 token balances (chains with a data-capable upstream) for an address. Chains: e.g. eth_mainnet, base_mainnet, arbitrum_one, optimism_mainnet, polygon_pos, solana_mainnet.
- get_history: Recent asset transfers (sent + received, newest first) for an address on chains with a data-capable upstream. EVM chains only in v1.

Resources:
- flexyield://plans: FlexYield subscription plans: prices in integer USD cents, billing interval, and rate limits.
- flexyield://getting-started: How to go from zero to a relayed JSON-RPC request on FlexYield.
- flexyield://reliability: Measured per-chain gateway reliability: uptime over 24h/7d/30d windows and latency percentiles (last 24h), from synthetic probes every 5 minutes.

## Pages

- Home: https://flexyield.io/
- Docs (API reference): https://flexyield.io/docs
- Pricing: https://flexyield.io/pricing
- Status (measured per-chain uptime and latency): https://flexyield.io/status
- Sign up: https://flexyield.io/registration/new