9 Best Insider Trading APIs in 2026
Updated 2026-09-04. By Theodor Nielsen, founder of Form4API. Every fact below is restated from Form4API's own published, live-checked comparison pages — see each entry's link for the full detail and its check date.
Answer
Nine named providers come up most often for U.S. insider trading data: Form4API, sec-api.io, StockInsider.io, edgar.tools, EdgarTools (the open-source library), EODHD, Kaleidoscope, Quiver Quantitative, and Unusual Whales. Ranked below by insider-data specialization — dedicated insider/SEC-filing specialists first, providers where insider data is one endpoint inside a broader platform last — not by price or feature count. Each entry states one standout fact and one honest limitation, then links to a full side-by-side comparison. For a category-based framing instead (how to choose, not who's who), see the buyer's guide.
At a glance
For a 30-second scan before reading further: what each provider is best for, and what its free tier (if any) actually looks like.
| Provider | Best for | Free tier |
|---|---|---|
| 1. Form4API | Real-time insider alerts and screening | 500 calls/day, forever, no card |
| 2. sec-api.io | Full SEC-filing breadth and deep Form 4/5 history | 100 calls total, one-time trial |
| 3. StockInsider.io | Consumer-style insider research with named trackers | None confirmed for API use |
| 4. edgar.tools | MCP-first research across the broader SEC corpus | 14-day trial (time-boxed) |
| 5. EdgarTools (the library) | Ad-hoc Python research, run locally | Free forever, open source, no key |
| 6. EODHD | Teams already paying for broad market data | None for insider data ($59.99/mo minimum) |
| 7. Kaleidoscope (kscope.io) | One key across many data types, for institutional buyers | Not found — every path is "Contact Sales" |
| 8. Quiver Quantitative | Congressional and alt-data breadth alongside insider trades | None ($25-30/mo floor, but insider data needs $62.50-75/mo) |
| 9. Unusual Whales | Options flow and dark pool as the primary need | None — cheapest is a $50/week paid trial |
Sourced from each provider's dedicated comparison page below; figures change over time — verify current terms before deciding.
How this is ordered
By insider-data specialization, stated plainly rather than left implicit. The first five entries are providers whose core product is insider trading data or the SEC filings it comes from. The last four are broader market-data or alternative-data platforms where insider transactions are one endpoint (or a handful) inside a much larger catalogue — genuinely useful if that breadth is what you need, but a different shape of product than a dedicated insider-data API. This is not a ranking by price, feature count, or a composite score, and it is not a claim that #1 is right for every reader — each entry names its own honest limitation for exactly that reason.
The list
1. Form4APIThis is us
The anchor entry, and the one dimension every other row on this page is measured against: a dedicated U.S. insider-data specialist covering Form 4, Form 144, and 13F-HR, plus congressional STOCK Act trades. The standout fact is the combination no other provider here matches — a 500-calls/day free tier that never expires, self-serve HMAC-signed webhooks, and a rolling ingestion-latency figure published live on /status rather than asserted once. The honest limitation: it is deliberately narrow — no options flow, no dark pool, no broader SEC-filing corpus beyond insider-adjacent forms.
The Form4API insider trading API →2. sec-api.io
The broadest SEC-filing specialist in this list: 400+ form types, dedicated AAER/enforcement datasets, and Form 3/4/5 history running 2003 to present across 11.4M transactions. The standout fact is that history depth — nobody else here comes close. The honest limitation: its free tier is 100 calls total, a one-time trial rather than a daily allowance, and its real-time option is a WebSocket stream gated to the $199+/mo Business tier, with no webhook product at any price.
Full sec-api.io comparison →3. StockInsider.io
A consumer-facing insider-research product — screener, charts, an AI chat/sentiment layer, and named tracker pages for Congress, Donald Trump, and Warren Buffett — with API access bolted on. The standout fact is also its biggest caution flag: its own two pricing pages disagree by 5x on where API access actually starts ($20/mo per one page's FAQ, $99/mo per the dedicated API page). No confirmed free, ongoing API tier either way.
Full StockInsider.io comparison →4. edgar.tools
A newer, MCP-first entrant built around tools-based access to the wider SEC filing corpus, not just insider transactions. The standout fact is the design center — MCP as the primary interface, per its own positioning. The honest limitation, and the reason this entry reads thinner than the others: edgar.tools' own pricing and docs pages return a Cloudflare bot challenge to every automated request, so specific tier prices could not be independently verified for this comparison — what is stated here is its own relayed positioning (14-day trial, tier-gated tools), not confirmed numbers.
Full edgar.tools comparison →5. EdgarTools (the library)
Not the API company above — this is the free, MIT-licensed open-source Python library (github.com/dgunning/edgartools), with broad SEC form coverage, no API key, and no rate limit. The standout fact: genuinely free with no paid tier required, and well suited to notebook-style exploration. The honest limitation: it is a library you run yourself, not a hosted service — no webhooks, no push, no formal SLA, and Python only.
Full EdgarTools comparison →6. EODHD
A broad market-data platform — end-of-day and intraday prices, fundamentals, options — where insider transactions are one Form-4-only endpoint. The standout fact: convenient if you already need the rest of its catalogue. The honest limitation: insider data requires the $59.99/mo Fundamentals tier at minimum, refreshes on a daily batch rather than in real time, and each insider-transactions call costs 10x the normal quota.
Full EODHD comparison →7. Kaleidoscope (kscope.io)
A genuinely broad financial-data platform — SEC filings, SEDAR Canadian filings, 13F holdings, M&A deals, earnings transcripts, and more, described on its own site as 17-18 data APIs under one key, plus AI summarization and chat. The standout fact is that breadth. The honest limitation: it publishes no self-serve pricing anywhere — every path to API or MCP access is a sales-contact form — and its documented insider-transactions endpoint is scoped to one ticker or CIK per call, not a filterable, cross-company feed.
Full Kaleidoscope comparison →8. Quiver Quantitative
A broad congressional and alternative-data platform — lobbying disclosures, government contracts, executive compensation, corporate patents, politician net worth — with insider trades as one dataset among many. The standout fact: real depth on the political/alt-data side Form4API doesn't attempt. The honest limitation: its cheapest Hobbyist plan ($25-30/mo) does not include Insider Trading data at all — that requires the next tier up, Trader, at $62.50-75/mo — and neither self-serve tier grants commercial-use rights.
Full Quiver Quantitative comparison →9. Unusual Whales
A large options-flow-first market-data platform — dark pool activity, Greek exposure, volatility, and more, spanning "100+ endpoints across 19 categories" per its own copy, with a genuinely well-built MCP server (50+ tools). The standout fact: that breadth and a real MCP server most competitors here don't have. The honest limitation: insider trades are one small category — 4 of those 100+ endpoints — there is no free tier at all, and its terms restrict self-serve access to personal, non-commercial use.
Full Unusual Whales comparison →Frequently asked questions
What are the best insider trading APIs in 2026?
It depends on what "best" means for your use case, which is the reason this page is a ranked list with links rather than a single answer. Ordered by insider-data specialization (narrowest and most insider-focused first, broadest platforms last): Form4API, sec-api.io, StockInsider.io, edgar.tools, EdgarTools (the open-source library), EODHD, Kaleidoscope, Quiver Quantitative, and Unusual Whales. Each has a genuinely different best-fit reader — see the entry-by-entry breakdown above, or the category-based buyer's guide for how to evaluate the dimensions that matter regardless of which named provider you pick.
What is the cheapest way to get started with insider trading data?
Two genuinely free options exist among the nine: Form4API's API (500 calls/day, forever, no credit card) and EdgarTools, the free open-source Python library (no key, no rate limit, but you run it yourself and get no push notifications). Every other provider on this list either has no free tier at all (Kaleidoscope, Quiver Quantitative, Unusual Whales), a one-time trial rather than a recurring allowance (sec-api.io: 100 calls total; edgar.tools: 14 days), or an unconfirmed/disputed free path (StockInsider.io).
Which insider trading API can I evaluate without talking to sales?
Form4API, sec-api.io, EODHD, and Unusual Whales all publish self-serve pricing and let you sign up or start a paid trial without a sales conversation, though only Form4API and EdgarTools' free tiers cost nothing to start. Kaleidoscope publishes no self-serve pricing anywhere — every path to its API is a "Contact Sales" form. Quiver Quantitative's main pricing page redirects anonymous visitors to a signup form, though its numbers are published without a login on a separate subdomain (api.quiverquant.com/pricing). edgar.tools' pricing and docs pages returned a bot-verification challenge to every automated check attempted for this comparison, so its self-serve friction, if any, could not be independently confirmed.
How was this list ordered?
By insider-data specialization, stated plainly rather than left implicit: dedicated insider/SEC-filing specialists first (Form4API, sec-api.io, StockInsider.io, edgar.tools, EdgarTools), then providers where insider data is one endpoint inside a broader market-data or alt-data catalogue (EODHD, Kaleidoscope, Quiver Quantitative, Unusual Whales). This is not a ranking by price, by feature count, or by any composite score — it is one explicit, defensible axis, and every entry states its own honest limitation so the ordering doesn't stand in for a full recommendation.
Get more from this data
Continue reading
- The category-based buyer's guide: how to choose an insider trading API →
- All insider trading data APIs compared, side by side →
- Is there a free insider trading API? Nine providers checked →
- Should you scrape SEC EDGAR yourself, or use an API? →
- The Form4API insider trading API →
- All SEC filing guides →
- Form4API reference docs →