What is the best fund data API for developers?

What "best for developers" means

• Time to first call measured in minutes, not procurement cycles.
• One shape for every fund house, so the parser is written once.
• Documentation a machine can read: OpenAPI, typed SDKs, an AGENTS.md, an MCP server.
• Predictable cost per request with a free tier for evaluation.
• Provenance: every figure traceable to a published document with a date.

How the options compare

What you get from FundFacts API

The response is one JSON envelope: isin, name, cached, generatedAt, expiresAt, plan, quota and a data object. Inside data you get keyFacts (asset class, currency, fund size, inception date, distribution policy, number of holdings), headlineMetrics (TER, AUM, 3-year volatility and Sharpe, yield to maturity and duration for bond funds), riskRating (the 1–7 KID indicator), profile (a rule-based classification: kind, category, risk band, region focus, sector tilt), topHoldings, sector, geography, region, assetAllocation, creditQuality, maturity, calendarReturns, annualisedReturns, cumulativePerformance, indexedPerformance, metrics (max drawdown, P/E, income yield…), sfdrArticle, costs (PRIIPs entry, exit, ongoing, transaction and performance fees, reduction in yield) and dataAsOf, the date of the underlying figures.

javascript
// npm install @fundfactsapi/sdk
import { FundFacts } from "@fundfactsapi/sdk";
const ff = new FundFacts({ apiKey: process.env.FUNDFACTS_API_KEY });
const fund = await ff.getFund("IE00B4L5Y983"); // iShares Core MSCI World UCITS ETF
console.log(fund.data.headlineMetrics.ter, fund.data.riskRating, fund.data.topHoldings[0], fund.data.dataAsOf);

The Free plan gives 5 lookups a month without a card (2 PDF factsheets), enough to check a few of the funds you care about. Starter is $9.99 a month for 60 requests (30 PDF factsheets) with portfolio look-through, holdings overlap and batch calls of 10 ISINs and the AI companion kit. Pro is $49 for 1,000 requests (500 PDF factsheets), 50 ISINs per call, white-label factsheets, document extraction and a commercial licence. Scale is $249 for 10,000 requests, batches of 200, a change feed, webhooks and bulk export.

When to pick something else

• You need ratings, style boxes or analyst research: Morningstar or LSEG Lipper.
• You need a terminal or cross-asset analytics: Bloomberg or LSEG Workspace.
• You need daily prices and nothing about the fund itself: a market-data API.
• Fund data is your product and you want to own the pipeline: build it; the comparison with building your own parser lists what that involves.

The provider comparison has the longer version.