// buyer's guide
Insider Trading API Comparison — 2026 Buyer's Guide
Updated 2026-06-10. By Theodor Nielsen, founder of Form4API.
// answer
We compared 7 insider trading APIs in June 2026 on free tier, entry pricing, webhook support, Form 4 / Form 144 / 13F-HR coverage, and self-serve checkout. Form4API has the most generous free tier (15,000 requests/month, no credit card) and webhooks at $49/month. SEC-API.io covers all SEC forms but limits the free tier to 100 lifetime requests. WhaleWisdom is the 13F specialist. QuiverQuant and FMP are the lowest-cost entry points. Full comparison below.
At-a-glance comparison
The table below covers the 7 most commonly compared APIs for SEC insider trading data as of June 2026. Columns are ordered by Form4API first (this site), then alphabetically by competitor. "Not documented" means the feature may exist but is not described in the vendor's public documentation at the time of review.
| Feature | Form4API | SEC-API.io | StockInsider | QuiverQuant | WhaleWisdom | API Ninjas | FMP |
|---|---|---|---|---|---|---|---|
| Free tier | 15,000/mo (500/day) | 100 lifetime | None | None | 2yr historical, 50 filers/qtr | Limited | Generous |
| Credit card for free tier | No | Not documented | — | — | No | Not documented | Not documented |
| Cheapest paid plan | $49/mo | $49/mo | $99/mo | $30/mo | $300/yr (~$25/mo) | $39/mo | $19/mo |
| Form 4 (insider transactions) | ✓ | ✓ | ✓ | ✓ | — | ✓ (Form 3/4/5) | ✓ |
| Form 144 (proposed sales) | ✓ | ✓ | — | Partial | — | — | — |
| 13F-HR (institutional holdings) | ✓ | ✓ | — | ✓ | ✓ (specialist) | — | ✓ |
| Webhooks / real-time push | ✓ (Pro+, $49/mo) | Business only ($199/mo) | ✓ (Pro+, $299/mo) | — | — | — | — |
| Python SDK | ✓ | ✓ | Not documented | Not documented | Not documented | Not documented | Not documented |
| JavaScript SDK | ✓ | Not documented | Not documented | Not documented | Not documented | Not documented | Not documented |
| Self-serve checkout | ✓ (Stripe) | Not documented | Email-gated | ✓ | ✓ | ✓ | ✓ |
| 10b5-1 plan flag per transaction | ✓ | Not documented | Not documented | — | — | — | — |
| Amendment-aware parsing | ✓ | Not documented | Not documented | — | — | — | — |
Data verified June 2026 via vendor pricing pages and public documentation. "—" means the feature is not offered or not documented.
Pricing breakdown
Prices below are monthly billed unless otherwise noted. Annual-billing discounts exist at some vendors (SEC-API.io, QuiverQuant, WhaleWisdom) and can reduce cost by 10–20%. Form4API does not currently offer annual discounts.
Form4API
- •Free — 15,000/mo
- •$49/mo Pro — 1.5M/mo + webhooks
- •$149/mo Business — Form 144 + 13F-HR
- •$499/mo Enterprise — unlimited + SLA
SEC-API.io
- •Free — 100 lifetime
- •$49/mo Personal (~$55 billed monthly)
- •$199/mo Business — websocket + all forms
- •Custom Enterprise
StockInsider
- •No free tier
- •$99/mo Starter — 10,000/mo
- •$299/mo Pro — 100,000/mo + webhooks
- •Custom
QuiverQuant
- •No free tier
- •$30/mo Hobbyist ($300/yr)
- •$75/mo Trader ($750/yr)
- •Custom Commercial
WhaleWisdom
- •Free — 2yr historical, 50 filers/qtr
- •$300/yr Pro — 200 filers/qtr
- •$90/3-mo Pro quarterly
- •Enterprise — unlimited, live feed
API Ninjas
- •Limited free
- •$39/mo Developer — 100,000/mo
- •$99/mo Pro — 500,000/mo
- •$199/mo Ultra
FMP
- •Generous free tier
- •$19/mo Starter
- •$49/mo Professional
- •$99/mo+
Prices verified June 2026. All prices in USD unless noted. Vendor pricing may change — check each vendor's pricing page for current rates.
Coverage matrix
The table below maps specific capabilities across all 7 vendors. Note that "✓" means the feature is documented; "—" means it is not covered or not publicly documented. Partial coverage means the feature exists but with significant limitations relative to a full implementation.
| Capability | Form4API | SEC-API.io | StockInsider | QuiverQuant | WhaleWisdom | API Ninjas | FMP |
|---|---|---|---|---|---|---|---|
| Form 4 transactions | ✓ | ✓ | ✓ | ✓ | — | ✓ | ✓ |
| Form 4/A amendment resolution | ✓ | — | — | — | — | — | — |
| Form 144 proposed sales | ✓ | ✓ | — | Partial | — | — | — |
| 13F-HR holdings | ✓ | ✓ | — | ✓ | ✓ | — | ✓ |
| 10b5-1 plan flag | ✓ | — | — | — | — | — | — |
| Cluster buy/sell signals | ✓ | — | — | — | — | — | — |
| Webhooks (entry plan) | ✓ | — | — | — | — | — | — |
| Congressional trades / alt-data | — | — | — | ✓ | — | — | — |
| Deep 13F portfolio analytics | — | — | — | Partial | ✓ | — | — |
| Full EDGAR breadth (all forms) | — | ✓ | — | — | — | — | Partial |
| Financial statements (10-K/Q) | — | ✓ | — | — | — | — | ✓ |
| Python + JS SDKs | ✓ | Python only | — | — | — | — | — |
| MCP server (AI assistants) | ✓ | — | — | — | — | — | — |
Use case → recommended vendor
The "best" insider trading API depends on what you are building. The table below maps specific use cases to the vendor most suited to them. Where a competitor is the better fit, we say so.
“I want to monitor insider purchases with a real-time webhook”
→ Form4API
Webhooks available on the $49/mo Pro tier — the only API in this list that includes real-time push at the entry paid price. Free tier gives you 15,000 calls/month to prototype.
“I need full SEC EDGAR access — not just insider filings”
→ SEC-API.io
SEC-API.io parses all ~350 SEC form types including 10-K, 10-Q, 8-K, S-1, proxy statements, and XBRL-to-JSON. If your pipeline needs financial statements alongside insider data, SEC-API.io covers both.
“I need deep 13F hedge-fund analytics — sector views, multi-quarter trends”
→ WhaleWisdom
WhaleWisdom is purpose-built for 13F analysis. It surfaces sector allocation history, hedge fund return attribution, and detailed position changes that general-purpose APIs do not calculate. Caveat: Form 4 insider data is not covered.
“I am an indie developer with a hobbyist budget”
→ QuiverQuant
QuiverQuant's Hobbyist tier at $30/month (or $300/year) is the lowest cash entry point for a paid API in this space. It also covers alternative data (congressional trades, Reddit sentiment, lobbying filings) alongside insider data — broad coverage per dollar.
“I need all financial APIs under $20/month — insider data plus financials”
→ FMP (Financial Modeling Prep)
FMP starts at $19/month and includes Form 4 insider transactions alongside income statements, balance sheets, earnings calendars, and other financial data. If insider data is one signal among many in a broad financial-data pipeline, FMP offers the best coverage-per-dollar.
“I want a free tier I can realistically prototype with before committing”
→ Form4API
The Form4API free tier gives 500 requests per day (15,000/month) — no credit card, no expiry. The next most generous free tier in this list is WhaleWisdom (historical 13F only). All other competitors either require payment immediately or offer a token free allocation.
“I only need Form 4 data globally (non-US markets) or need a pay-per-call model”
→ API Ninjas
API Ninjas covers Form 3/4/5 filings and operates a pay-per-call model with a free tier. If you need simple per-call billing without a monthly subscription or you're building a low-volume tool, API Ninjas is worth evaluating.
Vendor profiles
Form4API
Form4API is the only API in this comparison built exclusively for insider trading filings — Form 4 (transactions), Form 144 (proposed sales), and 13F-HR (institutional holdings). It ingests directly from EDGAR, resolves Form 4/A amendments automatically, flags 10b5-1 pre-scheduled trades per transaction, and fires HMAC-signed webhooks within a median of 3 minutes of filing publication. The free tier gives 15,000 requests per month with no credit card. Python and JavaScript SDKs are maintained at the same version cadence as the REST API. A Model Context Protocol (MCP) server is available for use with AI coding assistants.
Best for: developers who need Form 4 / Form 144 / 13F-HR data with webhook push, insider-specific enrichment (10b5-1 flagging, amendment resolution, cluster signals), and a genuine free tier for prototyping. See /docs for the full API reference and /pricing for the plan details.
SEC-API.io
SEC-API.io is a general-purpose EDGAR API covering all ~350 SEC form types. Its core value proposition is breadth: 10-K annual reports, 10-Q quarterly filings, 8-K material events, DEF 14A proxy statements, S-1 IPO prospectuses, and XBRL-to-JSON structured financial data extraction alongside insider filings. Entry paid tier starts at $49/month (approximately $55 billed monthly). Real-time websocket access requires the $199/month Business tier. Free allocation is 100 lifetime requests.
Best for: applications that need financial statements, event filings, or XBRL data alongside insider transactions. Not the best choice if insider data alone is the primary need — the free tier is too limited for meaningful prototyping, and webhooks require a 4x price jump from Form4API. sec-api.io
StockInsider.io
StockInsider.io is focused on Form 4 insider transactions and webhooks, similar in DNA to Form4API. Key differences: no free tier, entry plan starts at $99/month (10,000 requests/month), webhooks only available on the $299/month Pro tier, and Form 144 and 13F-HR coverage is not documented. The 10,000 request/month quota on the entry plan is significantly lower than Form4API's 1.5M/month at the same price point.
Best for: developers already integrated into the StockInsider ecosystem. The higher price point and lower quotas make it hard to recommend as a first choice over Form4API for new projects. stockinsider.io
QuiverQuant
QuiverQuant is an alternative data aggregator that includes insider trading alongside congressional trades, Reddit sentiment, corporate lobbying, and other non-traditional signals. Its Hobbyist tier at $30/month is the lowest cash entry point among paid plans in this comparison. There is no free tier. Form 4 coverage is included; Form 144 support is partial; webhooks are not available.
Best for: quant researchers and hobbyists who want a broad alternative data feed at a low price — particularly if congressional trades, Reddit, or lobbying signals are relevant alongside insider data. api.quiverquant.com
WhaleWisdom
WhaleWisdom is the clear specialist for 13F-HR institutional holdings data. It offers detailed sector allocation history, hedge fund return attribution, position change analytics, and multi-quarter trend views that general-purpose APIs do not compute. Free tier gives 2 years of historical 13F data with a 50-filer-per-quarter API limit. Pro tier ($300/year or ~$90/3-month) increases to 200 filers per quarter. Enterprise gives unlimited live feed access.
Best for: 13F-specific analytics — tracking institutional accumulation trends, building hedge fund clone strategies, or monitoring position changes at the sector level. Not suitable as a Form 4 insider transaction source. whalewisdom.com
API Ninjas
API Ninjas provides a broad multi-domain API platform covering weather, sports, geography, and financial data including SEC Forms 3, 4, and 5. Its insider trading endpoint covers Form 4 at a basic level. Pricing starts at $39/month for the Developer tier (100,000 requests/month), with a limited free tier. No webhook support, no Form 144, no 13F-HR, no SDK documented.
Best for: developers who want a single multi-domain API subscription covering many data types, and for whom insider data is one small component of a broader application. api-ninjas.com
Financial Modeling Prep (FMP)
Financial Modeling Prep offers a broad financial data API — income statements, balance sheets, earnings calendars, stock screeners, and Form 4 insider transactions — at a starting price of $19/month. The free tier is generous relative to most competitors. 13F institutional holdings are covered. Form 144 and webhooks are not documented. No insider-specific enrichment (10b5-1 flagging, amendment reconciliation) is documented.
Best for: developers building broad financial-data applications where Form 4 insider data is one signal among many — earnings, financials, price data — and budget is a primary constraint. financialmodelingprep.com
Methodology and disclosure
This comparison page was compiled in June 2026 by Theodor Nielsen, the founder and developer of Form4API. Pricing and feature data were verified by visiting each vendor's public pricing page and documentation directly. Where information was not publicly documented, the relevant cell is marked "Not documented" rather than assumed.
We have tried to be factually accurate and editorially fair. The use-case recommendations above include cases where a competitor is the better fit for a given need. We do not receive referral fees from any of the vendors listed. This page is operated by Form4API — a named competitor in the comparison — so you should factor that into your evaluation.
Vendor pricing and features change frequently. If you spot an inaccuracy, email theodor@form4api.com. We update the page when notified of changes.
For data discipline: we rely on publicly documented features only. Vendor claims on marketing pages without supporting documentation are marked as "Not documented". We do not invent competitor features, capabilities, or pricing.
Frequently asked questions
What is the best insider trading API?
There is no single best insider trading API — the right choice depends on your use case. For Form 4 monitoring with webhooks and a generous free tier, Form4API is the strongest option. For full SEC EDGAR breadth, SEC-API.io covers all ~350 form types. For 13F hedge fund analytics, WhaleWisdom is the specialist. For hobbyist or low-budget projects, QuiverQuant ($30/mo) or FMP ($19/mo) offer the lowest entry price. See the use-case guide above for a more specific recommendation.
Which SEC Form 4 API has the best free tier?
Form4API offers the most generous free tier among the APIs compared here: 500 requests per day (15,000/month) with no credit card required and no expiry. The next closest is WhaleWisdom, which offers 2 years of historical 13F data with a 50-filer-per-quarter API limit — but this is 13F data only, not Form 4 insider transactions. SEC-API.io's free allocation is 100 requests total (lifetime), which is enough for a quick look but not sustained prototyping.
Does any insider trading API include webhooks on a free or entry plan?
Form4API includes one read-only webhook on the free tier and up to 5 webhook endpoints on the $49/mo Pro tier. No other API in this comparison offers webhook-level real-time push at an entry price point — SEC-API.io requires the $199/mo Business tier for its websocket stream, and StockInsider requires the $299/mo Pro tier. QuiverQuant, WhaleWisdom, API Ninjas, and FMP do not offer webhooks as of June 2026.
Is SEC-API.io the same as Form4API?
No. SEC-API.io and Form4API are separate, independent products with different scopes. SEC-API.io is a general-purpose EDGAR API covering all ~350 SEC form types. Form4API is specialized in insider trading filings: Form 4 (transactions), Form 144 (proposed sales), and 13F-HR (institutional holdings). Form4API also includes features specific to insider analysis, such as 10b5-1 plan flagging, amendment-aware transaction reconciliation, cluster buy/sell signals, and HMAC-signed webhooks at the entry price tier.
Can I get both Form 4 and 13F data from a single API?
Yes. Form4API, SEC-API.io, QuiverQuant, and FMP all provide both Form 4 insider transactions and 13F institutional holdings. Form4API is the only one in this list that joins both datasets in a single /v1/transactions response row — each transaction includes an institutionalOwnership block showing the current quarter AUM, QoQ trend, and top-3 13F-HR holders for that company, without requiring a second API call.
Are Form 144 filings available via API?
Form 144 (notice of proposed sale of restricted securities — filed before a discretionary insider sale) is covered by Form4API and SEC-API.io. StockInsider, API Ninjas, and FMP do not document Form 144 support as of June 2026. QuiverQuant has partial coverage. WhaleWisdom does not cover Form 144 (its focus is 13F).
Last verified June 2026 — pricing and features change frequently. Email theodor@form4api.com if you spot an inaccuracy.
// background reading
- What is SEC Form 4? Filing requirements and transaction codes →
- SEC Form 144 explained — notice of proposed sale →
- 13F-HR filings — institutional holdings explained →
- Cluster buy signals — why multiple insiders buying matters →
- Rule 10b5-1 plans — pre-scheduled insider trades →
- Form4API pricing →
- API documentation →