Table of Contents
◉ Introduction: Why Data Still Beats Gut Feel ◉ 1. FRED API — U.S. Macro Without the Paywall ◉ 2. SEC EDGAR — Text-Mined Fundamentals at Filing Speed ◉ 3. Alpha Vantage — Retail-Friendly Real-Time Feeds ◉ 4. Tiingo — Clean Daily OHLCV & News in One Key ◉ 5. Finnhub — Global Equities + Alt-Data Starter Pack ◉ 6. Stooq — Tick-Free, CSV-Ready History Back to 1962 ◉ 7. GDELT v3 — News Sentiment at Planet Scale ◉ 8. Coin Metrics Community — Institutional-Grade Crypto Signals ◉ 9. Quiver Quant — Congressional Trades & Reddit Talk in SQL ◉ 10. Nasdaq Data Link — Legacy “Quandl” Reborn ◉ Putting It Together: A Zero-Cost Data Pipeline ◉ Conclusion: Your 2025 Bookmark Checklist
Cheap leverage, flashy GUIs and TikTok influencers come and go, but for the retail quant clean, timely, permission-free data remains the only durable edge. In 2025 that edge is bigger than ever: regulators have opened APIs, crypto natives publish tick-by-tick ledgers and even Wall Street television chatter can be scraped in JSON. Yet the signal-to-noise ratio is brutal because free
often means undocumented, rate-limited or silently deprecated. This guide curates the ten sources that still deliver sustainable alpha for independent coders, back-test junkies and weekend portfolio hackers.
1. FRED API — U.S. Macro Without the Paywall
Why care? 675 000 + economic series from CPI to SOFR, updated intraday, with embargo times in machine-readable metadata. Access: one-line registration yields a lifetime key; median response <200 ms. 2025 update: St. Louis Fed added a Policy-Rate Uncertainty Index and daily Quits & Layoffs series in April.
Pro tip: Pipe FRED JSON into a pandas-based SQLite cache; refresh only series flagged realtime_start/end newer than your last pull to avoid throttling.
2. SEC EDGAR — Text-Mined Fundamentals at Filing Speed
The regulator’s bulk feeds now expose every XBRL tag, plus full-text HTML, minutes after acceptance. EDGAR Next (March 2025) modernised token auth and doubled throughput limits. Parsed 10-Q embeddings give you management-tone scores before sell-side models refresh.
Catch: Filings posted after 5 : 30 p.m. ET may carry a D-1 timestamp; version your datastore by accessionNumber, not CIK, to track amendments.
3. Alpha Vantage — Retail-Friendly Real-Time Feeds
Alpha Vantage still grants 500 free requests/day for equities, FX, crypto and the new Options Greeks endpoint (Jan 2025). CSV payloads mean no JSON-parsing overhead; outputsize=full returns 20 + years of OHLCV in one call.
Watch-out: Burst limits are 5 calls/min; stagger cron jobs or hit HTTP 429s mid-back-test.
4. Tiingo — Clean Daily OHLCV & News in One Key
Tiingo’s free tier still delivers split-adjusted U.S. equities back to 1960, IEX real-time quotes, crypto pairs and a low-latency news stream—all behind a single token. Daily bars arrive ~9 p.m. ET, perfect for end-of-day factor runs.
Bonus: WebSocket support lets you stream quotes into a Jupyter notebook without spinning up Kafka.
5. Finnhub — Global Equities + Alt-Data Starter Pack
Free accounts enjoy 60 calls/min for price, fundamentals, insider trades, corporate actions, ESG scores and macro surprises across 70 + exchanges. The 2025 refresh added a Real-Time Options Chain endpoint and doubled historical earnings to ten years.
Integration hack: Use Finnhub websockets for quotes and Tiingo daily bars; symbols align to IEX style so merges are trivial.
6. Stooq — Tick-Free, CSV-Ready History Back to 1962
Stooq’s anonymous CSV dumps cover global equities, futures, indices and FX, refreshed before European lunch. Daily history on the S&P 500 stretches to Jun 26 2025 (>14 000 rows). No key, no email—just wget.
Downside: Schema tweaks are silent; pin column order by header, not index.
7. GDELT v3 — News Sentiment at Planet Scale
GDELT ingests 700 K media items/day, tags entities in 100 + languages and publishes a 15-minute-lagged CSV feed. May 2025 research showcased a macro-alpha model built purely on GDELT sentiment factors.
Latency trick: Add EXTERNALS=true to filter only finance-tagged URLs and cut payload ≈80 %.
8. Coin Metrics Community — Institutional-Grade Crypto Signals
The Community Network Data tier exposes 100 + on-chain and market metrics (realised cap, hash-rate, free-float supply) for the top 150 assets. Daily CSVs drop T+0 by 01 : 00 UTC, no auth.
Beware: File paths roll each January; crawl directories before syncing.
9. Quiver Quant — Congressional Trades & Reddit Talk in SQL
Quiver scrapes congressional disclosures, TikTok mentions, WSB sentiment, corporate lobbying and more. A 2025 REST API means /live/congresstrading returns filings within minutes.
Edge case: Rate-limits are by IP, not token—use a proxy pool for heavy back-fills.
10. Nasdaq Data Link — Legacy “Quandl” Reborn for 2025
Quandl’s free Wiki EOD and Continuous Futures sets remain under Nasdaq. Docs highlight a Sample Fundamentals pack and retain open metadata. Limit: 300 CSV calls/day—ample for nightly ETLs.
Automation tip: Reference api_key=${ENV[NDAQ_KEY]} inside your Airflow HTTP operator to keep secrets out of code.
Putting It Together: A Zero-Cost Data Pipeline
Link FRED macro drivers to Finnhub earnings beats, pipe Stooq bars into your factor library and overlay Quiver’s WSB sentiment—all in a single DuckDB file. Nightly pulls via GitHub Actions (2 000 free minutes/month) create a server-less, zero-cost lake house.
Need real-time? Funnel Alpha Vantage + Tiingo WebSockets into TimescaleDB, then enrich with GDELT bursts for risk-on/off dashboards. End-to-end latency: <3 s at $0/month.
Conclusion: Your 2025 Bookmark Checklist
Free data is no longer synonymous with stale CSVs. The ten sources above cover macro, micro, tick, alt-data and crypto—every building block a self-funded quant needs. Bookmark them, automate them, and spend your capital on trades, not terminals.
