Form4API vs StockInsider.io
Updated 2026-09-03. By Theodor Nielsen, founder of Form4API. Pricing and features checked September 2026 directly from stockinsider.io/insider-api and stockinsider.io/pricing.
Answer
StockInsider.io is a consumer-facing insider-trading research product — screener, charts, AI chat/sentiment, and named tracker pages — with API access bolted on. Its own two pricing pages disagree on where that API access actually starts: the dedicated /insider-api page prices a standalone API ladder from $99/mo with no free tier, while the /pricing page’s FAQ states API access is included starting at its $20/mo Pro plan. Form4API has one price list, a 500-calls/day free tier that never expires, self-serve HMAC-signed webhooks from $19/mo, and an MCP server where 22 of 35 tools work free. See the pricing discrepancy in full below.
A pricing page that disagrees with itself
stockinsider.io/insider-api publishes a standalone API pricing ladder: Starter $99/mo (10,000 API calls/month, all endpoints, email support), Professional $299/mo (100,000 calls/month, all endpoints plus webhooks, priority support, custom rate limits), and an Enterprise tier at custom pricing. The page's own header states "All plans include full API access" — implying $99/mo is the floor to reach the API at all.
stockinsider.io/pricing, a separate page for the same company's consumer product, tells a different story: it lists a free "Starter" tier, a $20/mo Pro tier for individual traders that includes "REST API access" in its feature list, and a $50/user/mo Team tier. Its FAQ section states outright: "API access is included with Pro, Team, and Enterprise plans." Both pages were checked live the same day; this page does not resolve the conflict in either direction — verify directly with StockInsider.io which number applies before budgeting for it.
Free tier: 500/day forever vs no confirmed free API path
Neither StockInsider.io pricing page describes a free, ongoing API allowance. The API-specific page has no free plan at all. The consumer product does have a free "Starter" tier (up to 100 searches/day, basic data, email/Telegram alerts), but its own FAQ excludes API access from that tier — API access is described as starting at the paid Pro plan.
Form4API's free tier is 500 calls a day (about 15,000/month), indefinitely, with no credit card required, covering every core endpoint and post-trade return field. Whichever of StockInsider.io's two numbers is accurate, evaluating its API costs at minimum $20/mo and possibly $99/mo before the first real test call.
Webhooks and MCP access
StockInsider.io's /insider-api page lists webhooks as a feature of the $299/mo Professional tier and above only — the $99/mo Starter API tier's feature list stops at "email support" and "basic documentation," with no webhook mention. Form4API includes self-serve, HMAC-signed webhooks starting at the $19/mo Starter plan, with a free read-only webhook on the $0 tier.
No MCP server, Model Context Protocol integration, or AI-agent tool access could be found on either StockInsider.io pricing page as of September 2026. Its AI features (an in-app chat and sentiment layer, per its /pricing page) appear to be a consumer-facing product feature, not a developer-facing MCP server the way Form4API's 35-tool MCP is.
When StockInsider.io may be the better fit
- You want a ready-made consumer research app, not just a data feed — charts, a screener, a real-time updated dashboard, and named tracker pages (Congress, Donald Trump, Warren Buffett, and others) bundled under one subscription.
- An AI chat/sentiment layer over insider data is more valuable to you than raw filterable API access — that's the product's stated core, per its own copy.
- $20/mo is genuinely enough to reach its API, per its own FAQ — if so, that undercuts Form4API's $19/mo Starter tier while also including the consumer dashboard. Verify this directly given the discrepancy above before relying on it.
Side-by-side
| Dimension | Form4API | StockInsider.io |
|---|---|---|
| API pricing floor | $0 free forever; $19/mo Starter unlocks commercial use | $99/mo (Starter) per /insider-api — but /pricing’s own FAQ states API access is included from its $20/mo Pro tier. The two pages disagree by 5x |
| Free tier for API use | 500 calls/day, ongoing, no credit card | None found on /insider-api. The consumer app’s free "Starter" tier (100 searches/day) explicitly excludes API access per the /pricing FAQ |
| Real-time delivery | HMAC-signed webhooks on every paid plan (Starter, $19/mo+) | Webhooks are listed only on the $299/mo "Professional" API tier and above — not on the $99/mo Starter tier |
| MCP / AI-agent access | 35 tools + 6 research prompts, self-serve; 22 of 35 free | Not found on /insider-api or /pricing — the product’s AI features are an in-app chat/sentiment layer, not an MCP server |
| Rate limits | 60 req/min (Free) up to 2,000 req/min (Enterprise), unlimited query depth on Pro+ | 10,000 calls/month (Starter) to 100,000 calls/month (Professional); no per-minute rate limit disclosed on either tier |
| Data scope | Form 4 + Form 144 + 13F-HR + Congress (STOCK Act) — insider-data specialist | "32+ endpoints" per its own copy, bundling insider transactions with AI sentiment scoring, a screener, and tracker pages (Trump, Buffett, and others) |
| Commercial-use terms | Explicit commercial-use license included from Starter ($19/mo) | Not addressed on either pricing page for the API specifically — verify directly before building a commercial product on it |
Sourced directly from stockinsider.io/insider-api and stockinsider.io/pricing as of September 2026. The two pages' disagreement on API pricing is noted rather than resolved. Vendors change pricing and features often; verify current terms directly before deciding.
Frequently asked questions
Does StockInsider.io have a free API tier?
No standalone free API tier could be found. StockInsider.io’s dedicated API page (/insider-api), checked September 2026, lists three plans — Starter $99/mo, Professional $299/mo, Enterprise (custom) — with no free option and the header copy "All plans include full API access." Its separate consumer-product pricing page (/pricing) does show a free "Starter" tier (100 searches/day), but that page’s own FAQ says API access requires at least the $20/mo Pro plan. Either way, there is no ongoing, no-cost path to the API the way Form4API’s 500-calls/day free tier works.
Why do StockInsider.io’s two pricing pages show different numbers?
This page found a real discrepancy, not a stale cache: /insider-api (the API-specific page) states a standalone ladder starting at $99/mo for API access, with no mention of a cheaper path. /pricing (the consumer product’s page) lists a $20/mo "Pro" tier for individual traders and states in its own FAQ, "API access is included with Pro, Team, and Enterprise plans" — which would put API access at $20/mo, not $99/mo. Both quotes are accurate as pulled directly from StockInsider.io’s own live pages, checked the same day. This page states both rather than picking one; ask StockInsider.io directly which applies before budgeting for it.
What is the difference between Form4API and StockInsider.io?
StockInsider.io is primarily a consumer-facing product — a screener, charts, an AI chat/sentiment layer, and named tracker pages (for Congress, Donald Trump, Warren Buffett and others) — with API access as an add-on whose entry price its own two pages disagree about. Form4API is an API-first insider-data specialist: a 500-calls/day free tier that never expires, self-serve HMAC-signed webhooks from the $19/mo Starter plan, and an MCP server (35 tools, 6 research prompts, 22 of 35 free) with no consumer dashboard at all.
Does StockInsider.io have webhooks or an MCP server?
Webhooks: yes, but gated. "All endpoints + webhooks" appears only on the $299/mo "Professional" API tier and above — the $99/mo Starter API tier’s feature list does not include them. MCP: not found. Neither /insider-api nor /pricing mentions an MCP server, Model Context Protocol, or AI-agent tool access as of September 2026; its AI features are described as an in-app chat and sentiment layer for the consumer product, not a developer-facing MCP integration.
When should I use StockInsider.io instead of Form4API?
If the goal is a ready-made consumer research product — charts, a screener, named politician/investor tracker pages, and an AI chat layer over insider data, bundled under one subscription — StockInsider.io’s $20/mo Pro tier (if its own FAQ’s claim of included API access holds) is a reasonable, cheap starting point. If the goal is building on top of a documented, self-serve API with a genuine indefinite free tier, self-serve webhooks, and no pricing-page discrepancy to resolve first, Form4API is the more predictable choice.