# Nyx Fund Developer Platform — Full API Reference

> Machine-readable full reference for AI agents and coding assistants. Every fact here
> is generated from the same registries that power https://nyxchain.org/developers and the
> live `/api/v1/*` routes — it cannot drift from what those surfaces actually serve.
> See https://nyxchain.org/llms.txt for the shorter product-level summary.

## Trust Centre
- [Trust Centre](https://nyxchain.org/trust): vendor due-diligence questionnaire, NAV & valuation methodology, business & data continuity statement, and security & compliance roadmap — each document is also a downloadable PDF.

## Fund Data API (read-only — Authorization: Bearer <nyx_dk_ key>)
Base URL: https://nyxchain.org/api/v1. Reflects Nyx's own shadow NAV, reconciled against
your fund administrator — never an official book of record. A published demo key works
against every endpoint below with a synthetic fixture fund, zero signup required.

### GET /api/v1/fund/overview — Fund Overview
The fund's base currency, inception date, AUM target, share classes, and latest NAV summary.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
(no parameters)

Sample response (truncated):
```json
{
  "fund": {
    "baseCurrency": "USD",
    "inceptionDate": "2024-03-01",
    "aumTarget": "25000000.00"
  },
  "shareClasses": [
    {
      "name": "Class A",
      "currency": "USD",
      "mgmtFeeAnnualRate": "0.02",
      "perfFeeRate": "0.20",
      "hurdleAnnualRate": null,
      "crystallizationFrequency": "quarterly",
      "feeExempt": false,
      "status": "open"
    }
  ],
  "latestNav": {
    "valuationDate": "2026-07-20",
    "status": "complete",
    "grossAssetValue": "18624531.12",
    "netAssetValue": "18450210.44"
  }
}
```

### GET /api/v1/fund/positions — Positions
The fund's current row-level live positions (never paper-trading holdings).
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
(no parameters)

Sample response (truncated):
```json
{
  "totalValueUsd": "18450210.44",
  "positionCount": 6,
  "truncated": false,
  "rows": [
    {
      "asset": "BTC",
      "quantity": "112.35000000",
      "priceUsd": "64000.00",
      "valueUsd": "7190400.00",
      "sourceType": "exchange",
      "source": "Binance"
    },
    {
      "asset": "ETH",
      "quantity": "1850.00000000",
      "priceUsd": "3400.00",
      "valueUsd": "6290000.00",
      "sourceType": "exchange",
      "source": "Coinbase"
    },
    {
      "asset": "USDC",
      "quantity": "2650000.00000000",
      "priceUsd": "1.00",
      "valueUsd": "2650000.00",
      "sourceType": "wallet",
      "source": "Ethereum wallet"
    },
    {
… (truncated)
```

### GET /api/v1/fund/breakdown — Portfolio Breakdown
The fund's current portfolio breakdown by asset, source type, and venue.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
(no parameters)

Sample response (truncated):
```json
{
  "total_aum": 18450210.44,
  "rows": [
    {
      "asset": "BTC",
      "quantity": 112.35,
      "price_usd": 64000,
      "value_usd": 7190400,
      "source": "Binance",
      "source_type": "exchange"
    },
    {
      "asset": "ETH",
      "quantity": 1850,
      "price_usd": 3400,
      "value_usd": 6290000,
      "source": "Coinbase",
      "source_type": "exchange"
    },
    {
      "asset": "USDC",
      "quantity": 2650000,
      "price_usd": 1,
      "value_usd": 2650000,
      "source": "Ethereum wallet",
      "source_type": "wallet"
    },
    {
      "asset": "SOL",
      "quantity": 9800,
… (truncated)
```

### GET /api/v1/fund/exposure — Current Exposure
The fund's current gross/net/long/short/cash exposure snapshot.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
(no parameters)

Sample response (truncated):
```json
{
  "totalValueUsd": 18450210.44,
  "cashUsd": 2833810.44,
  "longUsd": 15616400,
  "shortUsd": 0,
  "grossUsd": 15616400,
  "netUsd": 15616400,
  "byAssetClass": [
    {
      "key": "crypto",
      "longUsd": 15616400,
      "shortUsd": 0,
      "grossUsd": 15616400,
      "netUsd": 15616400,
      "pctOfGross": 1
    },
    {
      "key": "stablecoin",
      "longUsd": 2650000,
      "shortUsd": 0,
      "grossUsd": 2650000,
      "netUsd": 2650000,
      "pctOfGross": 0.16969339924694551
    },
    {
      "key": "fiat",
      "longUsd": 183810.44,
      "shortUsd": 0,
      "grossUsd": 183810.44,
      "netUsd": 183810.44,
… (truncated)
```

### GET /api/v1/fund/exposure/series — Exposure Series
The fund's exposure evolution over a trailing window of days.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
  - days (integer, optional): —

Sample response (truncated):
```json
[
  {
    "date": "2026-06-21",
    "navRunId": "demo-nav-run-2026-06-21",
    "runStatus": "complete",
    "grossUsd": 15020000,
    "netUsd": 15020000,
    "longUsd": 15020000,
    "shortUsd": 0,
    "cashUsd": 2500000,
    "unpricedCount": 0
  },
  {
    "date": "2026-07-05",
    "navRunId": "demo-nav-run-2026-07-05",
    "runStatus": "complete",
    "grossUsd": 15340000,
    "netUsd": 15340000,
    "longUsd": 15340000,
    "shortUsd": 0,
    "cashUsd": 2580000,
    "unpricedCount": 0
  },
  {
    "date": "2026-07-20",
    "navRunId": "demo-nav-run-2026-07-20",
    "runStatus": "complete",
    "grossUsd": 15616400,
    "netUsd": 15616400,
    "longUsd": 15616400,
… (truncated)
```

### GET /api/v1/fund/nav/history — NAV History
The fund's daily NAV history with BTC/ETH reference prices.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
  - days (integer, optional): —

Sample response (truncated):
```json
[
  {
    "date": "2026-06-20",
    "nav_usd": 17510230.1,
    "btc_price": 61200,
    "eth_price": 3280
  },
  {
    "date": "2026-07-05",
    "nav_usd": 17960120.55,
    "btc_price": 62850,
    "eth_price": 3340
  },
  {
    "date": "2026-07-20",
    "nav_usd": 18450210.44,
    "btc_price": 64000,
    "eth_price": 3400
  }
]
```

### GET /api/v1/fund/pnl/attribution — P&L Attribution
P&L attribution between the NAV run on a given date and the immediately preceding usable run.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
  - date (string, required): —

Sample response (truncated):
```json
{
  "status": "ok",
  "fromDate": "2026-07-19",
  "toDate": "2026-07-20",
  "fromRunId": "demo-nav-run-2026-07-19",
  "toRunId": "demo-nav-run-2026-07-20",
  "navFromUsd": "18321810.12",
  "navToUsd": "18450210.44",
  "deltaNavUsd": "128400.32",
  "lines": [
    {
      "key": "price_effect",
      "amountUsd": "104200.00",
      "amountNum": 104200
    },
    {
      "key": "fee_effect",
      "amountUsd": "-14200.18",
      "amountNum": -14200.18
    },
    {
      "key": "new_position_effect",
      "amountUsd": "32400.50",
      "amountNum": 32400.5
    },
    {
      "key": "residual",
      "amountUsd": "6000.00",
      "amountNum": 6000
    }
… (truncated)
```

### GET /api/v1/fund/risk/var — Value at Risk (VaR)
A parametric Value-at-Risk estimate for the live portfolio.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
  - confidence (0.95 | 0.99, optional): —
  - horizonDays (1 | 10, optional): —
  - method ("sample" | "ewma", optional): —
  - windowDays (integer, optional): —

Sample response (truncated):
```json
{
  "simulated": true,
  "var": {
    "confidence": 0.95,
    "horizonDays": 1,
    "method": "sample",
    "varUsd": "742300.00",
    "navIncludedUsd": "18450210.44",
    "totalNavUsd": "18450210.44",
    "portfolioVolDaily": 0.032,
    "perAssetVol": [
      {
        "asset": "BTC",
        "volDaily": 0.0328,
        "observations": 180
      },
      {
        "asset": "ETH",
        "volDaily": 0.0403,
        "observations": 180
      },
      {
        "asset": "SOL",
        "volDaily": 0.0498,
        "observations": 180
      }
    ],
    "correlations": [
      {
        "a": "BTC",
… (truncated)
```

### GET /api/v1/fund/trial-balance — Trial Balance
The fund's trial balance as of a given date.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
  - asOf (string, optional): —

Sample response (truncated):
```json
{
  "asOf": "2026-07-20",
  "truncated": false,
  "totalDebit": "18450210.44",
  "totalCredit": "18450210.44",
  "rows": [
    {
      "code": "1000",
      "name": "Cash",
      "type": "asset",
      "normalSide": "debit",
      "totalDebit": "2650000.00",
      "totalCredit": "0.00",
      "balance": "2650000.00"
    },
    {
      "code": "1190",
      "name": "Digital Assets",
      "type": "asset",
      "normalSide": "debit",
      "totalDebit": "15800210.44",
      "totalCredit": "0.00",
      "balance": "15800210.44"
    },
    {
      "code": "2000",
      "name": "LP Capital",
      "type": "equity",
      "normalSide": "credit",
      "totalDebit": "0.00",
… (truncated)
```

### GET /api/v1/fund/capital-accounts — Capital Accounts
Per-investor capital accounts for the fund's latest complete NAV run.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
(no parameters)

Sample response (truncated):
```json
{
  "status": "ok",
  "navRunId": "demo-nav-run-2026-07-20",
  "valuationDate": "2026-07-20",
  "rows": [
    {
      "fee_account_id": "demo-series-a",
      "valuation_date": "2026-07-20",
      "lot_units": "10000.000000000000000000",
      "pfn_per_unit": "1848.09604400",
      "pre_fee_capital": "18480960.44000000",
      "own_mgmt_accrued": "30750.00000000",
      "own_perf_accrued": "0.00000000",
      "own_perf_banked": "0.00000000",
      "own_fees_total": "30750.00000000",
      "closing_capital": "18450210.44000000",
      "per_series_nav_per_unit": "1845.02104400"
    }
  ]
}
```

### GET /api/v1/fund/expenses — Expenses
The fund's expense accruals/payments.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
  - limit (integer, optional): —

Sample response (truncated):
```json
{
  "truncated": false,
  "rows": [
    {
      "expenseId": "demo-exp-001",
      "category": "fund_admin",
      "memo": "Q3 fund administration fee",
      "entryDate": "2026-07-01",
      "accruedUsd": "4200.00",
      "paidUsd": "4200.00",
      "outstandingUsd": "0.00",
      "reversed": false
    },
    {
      "expenseId": "demo-exp-002",
      "category": "audit",
      "memo": null,
      "entryDate": "2026-07-05",
      "accruedUsd": "3000.00",
      "paidUsd": "0.00",
      "outstandingUsd": "3000.00",
      "reversed": false
    },
    {
      "expenseId": "demo-exp-003",
      "category": "custody",
      "memo": "Monthly custody fee",
      "entryDate": "2026-07-10",
      "accruedUsd": "850.00",
      "paidUsd": "850.00",
… (truncated)
```

### GET /api/v1/fund/fee-terms — Fee Terms
The fund's configured management/performance fee terms and share classes.
Auth: Requires an Authorization: Bearer <API key> header (a nyx_dk_… developer key, minted from the developer console at /developers/console). Reflects Nyx's shadow NAV, reconciled against your fund administrator.
Parameters:
(no parameters)

Sample response (truncated):
```json
{
  "configured": true,
  "mgmtFeePct": "2.00",
  "perfFeePct": "20.00",
  "hurdleRatePct": null,
  "crystallizationFrequency": "quarterly",
  "mgmtFeeFrequency": "monthly",
  "unitBasePrice": "1000.00",
  "mgmtFeeBase": "pre_fee_nav",
  "shareClasses": [
    {
      "id": "demo-class-a",
      "name": "Class A",
      "currency": "USD",
      "mgmtFeePct": "2.00",
      "perfFeePct": "20.00",
      "hurdleRatePct": null,
      "crystallizationFrequency": "quarterly",
      "feeExempt": false,
      "status": "open"
    }
  ]
}
```

## Calculator API (no authentication)
Base URL: https://nyxchain.org/api/v1/calc. Stateless, illustrative fund-math endpoints —
every figure is computed only from the arguments passed in that single call, never
stored, never tied to a real fund.

### POST /api/v1/calc/fund-health-check — Fund Health Check
A free, 60-second operational health score for your crypto fund. Illustrative estimate only, not accounting/tax/investment advice. No authentication required.
Parameters:
  - aumUsd (number, optional): —
  - positionsCsv (string, optional): —
  - mgmtFeePct (number, optional): —
  - perfFeePct (number, optional): —
  - hasHwm (boolean, optional): —
  - hurdlePct (unknown, optional): —
  - navFrequency ("daily" | "weekly" | "monthly" | "quarterly", optional): —
  - reconFrequency ("daily" | "weekly" | "monthly" | "rarely", optional): —
  - lpReportingFrequency ("monthly" | "quarterly" | "adhoc", optional): —
  - backOfficeHeadcount (number, optional): —
  - hasFundAdmin (boolean, optional): —
  - hasAnnualAudit (boolean, optional): —

Sample request:
```json
{
  "aumUsd": 25000000,
  "positionsCsv": "",
  "mgmtFeePct": 2,
  "perfFeePct": 20,
  "hasHwm": true,
  "hurdlePct": null,
  "navFrequency": "monthly",
  "reconFrequency": "monthly",
  "lpReportingFrequency": "quarterly",
  "backOfficeHeadcount": 1,
  "hasFundAdmin": true,
  "hasAnnualAudit": false
}
```
Docs page: https://nyxchain.org/developers/calculators/fund-health-check · Try it: https://nyxchain.org/tools/fund-health-check

### POST /api/v1/calc/exposure-analysis — Exposure Analysis
Paste your positions, see gross, net, and concentration exposure instantly. Illustrative estimate only, not accounting/tax/investment advice. No authentication required.
Parameters:
  - positionsCsv (string, optional): —
  - navUsd (unknown, optional): —

Sample request:
```json
{
  "positionsCsv": "Asset,Value,Venue,Class\nBTC,320000,Coinbase,crypto\nETH,190000,Coinbase,crypto\nSPY,220000,Alpaca,etf\nAAPL,140000,Alpaca,equity\nTLT,90000,Alpaca,etf\nGC,60000,Manual,commodity\nUSDC,130000,Coinbase,stablecoin\nSeries B Private Co,50000,Manual,private",
  "navUsd": null
}
```
Docs page: https://nyxchain.org/developers/calculators/exposure-analysis · Try it: https://nyxchain.org/tools/exposure-analysis

### POST /api/v1/calc/nav-validator — NAV Validator
Check your month-end NAV roll-forward for arithmetic and fee errors in seconds. Illustrative estimate only, not accounting/tax/investment advice. No authentication required.
Parameters:
  - periodStart (string, optional): —
  - periodEnd (string, optional): —
  - openingNavUsd (number, optional): —
  - contributionsUsd (number, optional): —
  - withdrawalsUsd (number, optional): —
  - grossPnlUsd (number, optional): —
  - mgmtFeeUsd (number, optional): —
  - perfFeeUsd (number, optional): —
  - otherExpensesUsd (number, optional): —
  - reportedClosingNavUsd (number, optional): —
  - mgmtFeePct (number, optional): —
  - perfFeePct (number, optional): —
  - hasHwm (boolean, optional): —
  - lpRowsCsv (string, optional): —

Sample request:
```json
{
  "periodStart": "2026-06-01",
  "periodEnd": "2026-06-30",
  "openingNavUsd": 25000000,
  "contributionsUsd": 500000,
  "withdrawalsUsd": 0,
  "grossPnlUsd": 750000,
  "mgmtFeeUsd": 41667,
  "perfFeeUsd": 141667,
  "otherExpensesUsd": 10000,
  "reportedClosingNavUsd": 26056666,
  "mgmtFeePct": 2,
  "perfFeePct": 20,
  "hasHwm": true,
  "lpRowsCsv": ""
}
```
Docs page: https://nyxchain.org/developers/calculators/nav-validator · Try it: https://nyxchain.org/tools/nav-validator

### POST /api/v1/calc/fee-calculator — Hedge Fund Fee Calculator
See exactly what a 2/20 (or any) fee structure costs an LP over time. Illustrative estimate only, not accounting/tax/investment advice. No authentication required.
Parameters:
  - startingNavUsd (number, optional): —
  - annualGrossReturnPct (number, optional): —
  - mgmtFeePct (number, optional): —
  - perfFeePct (number, optional): —
  - hurdlePct (number | null, optional): —
  - hasHwm (boolean, optional): —
  - crystallization ("annual" | "quarterly", optional): —
  - horizonYears (number, optional): —

Sample request:
```json
{
  "startingNavUsd": 25000000,
  "annualGrossReturnPct": 15,
  "mgmtFeePct": 2,
  "perfFeePct": 20,
  "hurdlePct": null,
  "hasHwm": true,
  "crystallization": "annual",
  "horizonYears": 5
}
```
Docs page: https://nyxchain.org/developers/calculators/fee-calculator · Try it: https://nyxchain.org/tools/fee-calculator

### POST /api/v1/calc/operating-cost-calculator — Fund Operating Cost Calculator
Add up what your fund's back office actually costs every year. Illustrative estimate only, not accounting/tax/investment advice. No authentication required.
Parameters:
  - financeHireUsd (number, optional): —
  - fundAdminUsd (number, optional): —
  - complianceUsd (number, optional): —
  - riskDeskUsd (number, optional): —
  - lpReportsPerYear (number, optional): —
  - costPerReportUsd (number, optional): —
  - auditUsd (number, optional): —
  - legalUsd (number, optional): —
  - softwareUsd (number, optional): —
  - aumUsd (number, optional): —

Sample request:
```json
{
  "financeHireUsd": 120000,
  "fundAdminUsd": 100000,
  "complianceUsd": 80000,
  "riskDeskUsd": 40000,
  "lpReportsPerYear": 12,
  "costPerReportUsd": 8000,
  "auditUsd": 0,
  "legalUsd": 0,
  "softwareUsd": 0,
  "aumUsd": 25000000
}
```
Docs page: https://nyxchain.org/developers/calculators/operating-cost-calculator · Try it: https://nyxchain.org/tools/operating-cost-calculator

### POST /api/v1/calc/back-office-savings — Back-Office Savings Calculator
See what part of your back-office spend is realistically automatable. Illustrative estimate only, not accounting/tax/investment advice. No authentication required.
Parameters:
  - financeHireUsd (number, optional): —
  - fundAdminUsd (number, optional): —
  - complianceUsd (number, optional): —
  - riskDeskUsd (number, optional): —
  - lpReportsPerYear (number, optional): —
  - costPerReportUsd (number, optional): —
  - auditUsd (number, optional): —
  - legalUsd (number, optional): —
  - softwareUsd (number, optional): —
  - aumUsd (number, optional): —

Sample request:
```json
{
  "financeHireUsd": 120000,
  "fundAdminUsd": 100000,
  "complianceUsd": 80000,
  "riskDeskUsd": 40000,
  "lpReportsPerYear": 12,
  "costPerReportUsd": 8000,
  "auditUsd": 0,
  "legalUsd": 0,
  "softwareUsd": 0,
  "aumUsd": 25000000
}
```
Docs page: https://nyxchain.org/developers/calculators/back-office-savings · Try it: https://nyxchain.org/tools/back-office-savings

### POST /api/v1/calc/lp-report-grader — LP Report Grader
Grade your monthly LP update against what institutional investors expect. Illustrative estimate only, not accounting/tax/investment advice. No authentication required.
Parameters:
  - reportText (string, optional): —
  - reportingFrequency ("monthly" | "quarterly" | "adhoc", optional): —

Sample request:
```json
{
  "reportText": "",
  "reportingFrequency": "monthly"
}
```
Docs page: https://nyxchain.org/developers/calculators/lp-report-grader · Try it: https://nyxchain.org/tools/lp-report-grader

## MCP servers
- Public server (no auth): https://nyxchain.org/api/mcp/public — streamable HTTP, JSON-RPC 2.0. Tools: calc_fund_health_check, calc_exposure_analysis, calc_nav_validator, calc_fee_calculator, calc_operating_cost_calculator, calc_back_office_savings, calc_lp_report_grader, search_docs.
- Fund-scoped server (your own fund's real data, Authorization: Bearer <nyx_sk_ key>): https://nyxchain.org/api/mcp.
- Setup pages: https://nyxchain.org/developers/mcp

## Pricing
- Free ($0): 500 calculator requests per day; Public MCP server access; No card required — https://nyxchain.org/developers
- Developer ($49/mo): 100k calculator requests included per month; then $0.50 per 1,000 requests; API keys and a usage dashboard — https://nyxchain.org/signup
- Platform (Included with any Nyx Fund platform plan): Fund Data API: 250k requests included per month; then $0.75 per 1,000 requests; Everything in Developer — https://nyxchain.org/pricing
- Enterprise (From $499/mo): Custom request volume; Dedicated support; Contact us to scope your fund data needs — https://nyxchain.org/contact

## Frequently asked questions

### Developer platform
**Is there a fund reporting API?**
Yes. Nyx Fund's Developer API is a read-only REST API over Nyx Fund's live double-entry shadow ledger — twelve GET endpoints covering positions, NAV history, exposure, risk (VaR), P&L attribution, trial balance, capital accounts, expenses, and fee terms, plus seven no-auth calculator endpoints for fee and NAV math. Full docs live at nyxchain.org/developers.

**Is there a hedge fund NAV API?**
Yes. GET /api/v1/fund/nav/history returns Nyx's own shadow NAV history with BTC/ETH reference prices, computed from a real double-entry ledger and reconciled against your fund administrator — it is a shadow book that sits alongside your administrator, not a replacement for one, and requires an Authorization: Bearer nyx_dk_ developer key.

**Do I need to sign up to try the Nyx Fund API?**
No. A published demo developer key lets you call every Fund Data API endpoint against a synthetic fixture fund with zero signup, and the calculator endpoints need no key at all — see the quickstart at nyxchain.org/developers/quickstart.

**What does the Nyx Fund Developer API cost?**
Calculator access is free — 500 requests a day, no card required. The Fund Data API is metered: $49 a month for 100k requests (then $0.50 per 1,000), or included with the Nyx Fund platform plan (from $2,500/month, banded by fund AUM; 250k requests, then $0.75 per 1,000). Full pricing is at nyxchain.org/developers/pricing.

**Can AI agents call the Nyx Fund API directly?**
Yes. A public MCP server at /api/mcp/public speaks the Model Context Protocol over streamable HTTP with no authentication required, exposing the same seven calculators plus a doc-search tool to Claude Code, Claude Desktop, Cursor, ChatGPT, and any spec-compliant JSON-RPC client.

**Is the Fund Data API real fund data or a demo?**
Both. Every endpoint accepts the published demo key against a synthetic fixture fund for testing, and a real nyx_dk_ key (minted from your Nyx Fund dashboard) returns your own fund's live shadow-NAV data.

### Calculator API
**Is there an API to calculate hedge fund fees?**
Yes. POST /api/v1/calc/fee-calculator computes management and performance fees — including high-water mark and hurdle logic — from your fund's own inputs, with no authentication and no fund connection required. Results are illustrative estimates, not accounting or tax advice.

**Is there a fund fee calculator API?**
Yes. The same POST /api/v1/calc/fee-calculator endpoint is a stateless, illustrative fund fee calculator — pass management fee rate, performance fee rate, NAV, and prior high-water mark, and get back the fee breakdown, with no auth and no fund connection required.

**Is there a high-water mark calculation API?**
Yes, the same fee-calculator endpoint (POST /api/v1/calc/fee-calculator) applies a per-series high-water mark so performance fees accrue only on gains above the prior peak NAV — pass in your NAV history and fee terms and get back the fee breakdown.

**Do the Nyx Fund calculator endpoints require an API key?**
No. All seven calculator endpoints — fee, NAV validation, exposure analysis, operating cost, back-office savings, fund health, and LP report grading — are stateless and open with no authentication; an optional nyx_dk_ key only raises your daily rate limit.

**Are the calculator API results real fund figures?**
No. Every calculator endpoint returns illustrative estimates computed only from the arguments you pass in that single call — nothing is stored and nothing is tied to a real fund. Connect your exchanges in the full Nyx Fund product for live, audited figures.

**What calculators does the Nyx Fund API expose?**
Seven: the fee calculator (with high-water mark), NAV validator, exposure analysis, operating cost calculator, back-office savings calculator, fund health check, and LP report grader — the same deterministic engines behind the free tools at nyxchain.org/tools.

**What's the rate limit on the free calculator API?**
Five hundred requests per day with no card required, per caller. Passing an nyx_dk_ developer key raises that limit under the $49-a-month Developer plan or the bundled Platform plan.

### MCP
**Is there an MCP server for hedge funds?**
Yes. Nyx Fund runs two Model Context Protocol servers: a public one at /api/mcp/public with no authentication required for illustrative fund calculators, and a private, fund-scoped one at /api/mcp authenticated with your own nyx_sk_ key for your real fund's live shadow-NAV data.

**How do I connect Claude Code to the Nyx Fund MCP server?**
Run a single `claude mcp add` command with the public server URL (https://nyxchain.org/api/mcp/public) — no API key and no config file to edit. The exact command is on nyxchain.org/developers/mcp/claude-code.

**Does the public MCP server require an API key?**
No. The public server is free with no login and no key — it exposes seven calc_* calculator tools plus a search_docs tool, all stateless and illustrative.

**Can I connect my own fund's real data over MCP?**
Yes, on a separate server — /api/mcp — authenticated with your own nyx_sk_ key, minted from your Nyx Fund dashboard. It exposes the same read-only, shadow-NAV fund tools as the REST Fund Data API, never the public server's calculator tools.

**Which AI clients can connect to the Nyx Fund MCP server?**
Claude Code, Claude Desktop, Cursor, and ChatGPT (where your plan and workspace support MCP), plus any spec-compliant JSON-RPC MCP client — each has its own setup page at nyxchain.org/developers/mcp/<client>.

**What protocol does the Nyx Fund MCP server speak?**
Standard Model Context Protocol JSON-RPC 2.0 over streamable HTTP — send `initialize`, then `tools/list`, then `tools/call`. Both servers are stateless and single-response, and share the same JSON-RPC framing.

## Error envelope
Every REST v1 error response shares one JSON shape: { error: { code, message, status },
request_id }, alongside a X-Nyx-Api-Version: v1 response header on every
call (success or error). The MCP surfaces use standard JSON-RPC 2.0 error objects
instead ({ code, message } under an `error` key) — a missing/invalid tool name is
JSON-RPC code -32602, an unknown method is -32601, a malformed envelope is -32600, and a
rate limit is -32000 with an HTTP 429 status and a Retry-After header.