# Nexus

> Nexus is a full-stack blockchain data and transaction API for UTXO chains (Cardano, Bitcoin, Midnight), built by A.D. Labs LTD, the team behind GeroWallet. One account and one base URL cover chain data, DEX market data, wallet analytics, transaction building, and WebSocket streaming, with multi-provider failover for Cardano chain data.

## Key facts

- Base URL: https://nexus.gerowallet.io/api
- Auth: X-Api-Key header. API keys use the nxs_ prefix. Each key is scoped to one chain and one network.
- Cardano networks: mainnet, preprod, and preview on the same endpoints, selected with the ?network= query parameter.
- Machine-readable OpenAPI 3.1 spec: https://nexus.gerowallet.io/v3/api-docs
- Cardano failover upstreams: Nexus-operated indexers, Yaci, Koios, and Blockfrost, with per-provider health checks.
- Cardano chain data endpoint groups: accounts, addresses, assets and holders, blocks, epochs and protocol parameters, enriched stake pools, DReps and governance (Conway: proposals, votes, committee, constitution), scripts and datums, transactions, submit and evaluate.
- Market Data add-on: prices, OHLCV candles, pools, TVL and reserves, order books, swaps, top traders, NFT collections and sales across 11 indexed Cardano DEXes, plus ADA/USD candles.
- Wallet Analytics add-on: holdings, transaction history, and FIFO cost-basis P&L per wallet.
- Transaction Builder add-on: server-side UTXO selection and fee calculation for transfers, staking, and Conway governance actions. Returns unsigned CBOR; users sign with their own keys, so Nexus never holds private keys.
- WebSocket streaming: market-data topics on a 10-second cadence, plus Blueprints, self-serve on-chain event streams with UTXO or TRANSACTION granularity and REST backfill for replaying missed events.
- DEX aggregator: best-price swap routing across verified venues Minswap V1 and V2, WingRiders V1 and V2, Splash, and SaturnSwap. Non-custodial.
- MCP Server add-on: hosted Model Context Protocol endpoint so Claude and other AI agents can query Nexus data and tools with an API key.
- IPFS add-on: resolve, inspect, and pin content through a Nexus-hosted node.
- Bitcoin: chain data including ordinals, runes, and mempool. Midnight: network info, unshielded transaction build and submit, and DUST registration.
- Over-quota behavior: HTTP 429 with X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, and Retry-After headers. No auto-ban.

## Pricing (flat monthly, USD)

- Starter: $9/mo, 3M requests/month, 10 req/s, 2 API keys. Core API only: no add-ons, bundles, or WebSocket packages.
- Builder: $29/mo, 10M requests/month, 25 req/s, 4 API keys. Comes with a 7-day trial.
- Growth: $79/mo, 30M requests/month, 50 req/s, 7 API keys.
- Scale: $199/mo, 50M requests/month, 100 req/s, 13 API keys.
- Enterprise: $499/mo, 200M requests/month, 500 req/s, unlimited API keys, all add-ons and WS Unlimited included.
- Dedicated: from $2,000/mo, isolated infrastructure and a contractual SLA, via sales.
- Add-ons (Builder, Growth, Scale): Market Data $19/mo, Wallet Analytics $15/mo, Transaction Builder $19/mo, MCP Server $19/mo, IPFS $5/mo.
- Bundles (Builder, Growth, Scale; one per plan): Data $19/mo (Market Data + Wallet Analytics, $34 separately), Build + AI $19/mo (Transaction Builder + MCP Server, $38 separately), Complete $29/mo (all four, $72 separately). IPFS and WebSocket packages are not bundled.
- WebSocket packages (Builder, Growth, Scale): WS Starter $29/mo (2 connections, 100k messages), WS Pro $59/mo (10 connections, 2M messages), WS Unlimited $99/mo.
- There is no free tier. The trial is 7 days on the Builder plan.

## Pages

- [Home](https://nexus.gerowallet.io/): product overview and full pricing
- [Cardano API](https://nexus.gerowallet.io/cardano/): the Cardano hub, endpoint groups, streaming, market data, transaction builder, governance, FAQ
- [Blockfrost alternative](https://nexus.gerowallet.io/alternatives/blockfrost/): fact-checked Blockfrost vs Nexus comparison
- [API documentation](https://nexus.gerowallet.io/docs): full endpoint reference with request and response shapes
- [Blog](https://nexus.gerowallet.io/blog/)

## Full corpus

- Marketing site, full text of every indexable page: https://nexus.gerowallet.io/llms-full.txt (generated from the site at build time)
- API reference, every endpoint with request and response shapes: https://nexus.gerowallet.io/docs/llms-full.txt
- [Status](https://status.gerowallet.io): public live health for core subsystems
- [Get started](https://nexus.gerowallet.io/get-started/)

## Contact

- Sales: nexus@gerowallet.io
- Support: support@nexus.gerowallet.io