After-hours trading can move quickly when companies report earnings, issue guidance, announce corporate actions, or react to major news after the closing bell. Those moves do not always show up clearly if your workflow only checks regular-session closing prices.
FMP's Aftermarket Quote endpoint returns quote data for stocks traded outside normal market hours. The response includes fields such as bid price, ask price, bid size, ask size, volume, and timestamp. That makes it useful for developers and analysts who want to test how aftermarket quote data could fit into a watchlist, dashboard, alerting tool, or post-earnings monitoring workflow.
For free-plan users, this should be treated as a sandbox workflow. The Basic/free plan can be used to test the Aftermarket Quote endpoint for a supported symbol set, including AAPL, TSLA, AMZN, and 84 more supported symbols. It is useful for checking authentication, response structure, field parsing, and low-liquidity behavior before deciding whether a larger plan, real-time declaration, broader symbol coverage, or production infrastructure is needed.
Key Takeaways
- The Aftermarket Quote endpoint returns post-market quote fields such as bidPrice, askPrice, bidSize, askSize, volume, and timestamp.
- The Basic/free plan can be used as a sandbox to test endpoint behavior, supported-symbol access, response structure, and JSON parsing logic.
- Basic/free access is symbol-limited for this endpoint, with support shown for AAPL, TSLA, AMZN, and 84 more symbols.
- Nasdaq data is delayed by 15 minutes, and real-time access requires completion of the user declaration form.
- Aftermarket quote data is useful for monitoring and context. It should not be treated as a reliable prediction of the next trading session.
Regular Trading Sessions vs. Aftermarket Quotes
Regular-session trading usually has deeper liquidity, tighter spreads, and more active participation than after-hours trading. The core U.S. equity session runs from 9:30 AM to 4:00 PM ET.
After-hours trading generally runs from 4:00 PM to 8:00 PM ET. During this window, quotes can move in response to earnings releases, news, analyst updates, macro events, and other information that arrives after the regular session closes. Liquidity can be thinner, spreads can be wider, and some symbols may show limited or no quote activity.
That is why aftermarket quote data is best used as a monitoring input. It can help a dashboard show whether a stock is moving after the close, but the data should be interpreted with caution. A thin after-hours quote is not the same thing as a fully confirmed next-day market view.
Step 1: Create a Free FMP API Key
Before making requests, create an FMP account and copy your API key from the developer dashboard. Your key authenticates the request and lets you test supported endpoints from a script, notebook, API client, or application prototype.
You do not need a credit card to sign up for an FMP free plan, so this is a low-friction way to test endpoint behavior before choosing whether a larger workflow needs paid access. As your usage grows, it is also worth understanding the basics of managing your FMP account, including where to find your key, monitor access, and review plan-related settings.
For this workflow, the goal is to answer practical development questions:
- Can you authenticate successfully?
- Does the endpoint return aftermarket quote fields for a supported symbol?
- Can your script parse bid, ask, size, volume, and timestamp fields?
- Does your application handle empty, stale, or low-liquidity responses correctly?
- Do you need broader symbol coverage, higher request volume, or real-time access before scaling?
That makes the free plan useful for indie developers, students, analysts, and product builders who want to test aftermarket quote data before building a larger workflow around it.
Step 2: Retrieve Aftermarket Quotes for a Supported Symbol
With your API key ready, you can issue a direct HTTP GET request to test the Aftermarket Quote endpoint. On Basic/free access, this is best treated as an endpoint validation step. You can test the request format, supported-symbol behavior, JSON structure, quote fields, and timestamp handling.
The Aftermarket Quote endpoint is designed to return stock quote data outside regular trading hours.
Verified Request URL:
https://financialmodelingprep.com/stable/aftermarket-quote?symbol=AAPL&apikey=YOUR_API_KEY
Replace YOUR_API_KEY with your own key.
A sample response may look like this:
[
{
"symbol": "AAPL",
"bidSize": 1,
"bidPrice": 232.45,
"askSize": 3,
"askPrice": 232.64,
"volume": 41647042,
"timestamp": 1738715334311
}
]
Aftermarket data may only be meaningful during the post-market session. Depending on the symbol and request time, a response may be empty, delayed, stale, or show low-liquidity behavior. Nasdaq data is delayed by 15 minutes, and real-time access requires the user declaration form, which helps determine when real-time market data access is required for a user's intended use case.
Step 3: Understand the Aftermarket Quote Fields
The response gives you the fields needed to test a basic aftermarket quote view.
- symbol: The ticker requested in the API call.
- bidPrice: The highest price currently shown in the response that a buyer is willing to pay.
- bidSize: The reported bid size associated with the bid price.
- askPrice: The lowest price currently shown in the response that a seller is willing to accept.
- askSize: The reported ask size associated with the ask price.
- volume: The volume value returned in the quote response. Use it as a liquidity and activity field, and verify how it behaves for your symbol and request time.
- timestamp: A Unix millisecond timestamp showing when the quote record was updated.
These fields are quote fields, not order execution instructions. FMP provides the market data input. It does not provide trade execution, order routing, or brokerage functionality through this endpoint.
Step 4: What You Can Test With the Free Plan
The Basic/free plan is best used as a sandbox. It lets you test endpoint mechanics before deciding whether you need broader access.
For Aftermarket Quote, Basic/free access allows you to test the endpoint with specific constraints:
|
Free Plan Test Area |
What It Lets You Validate |
|
Authentication |
Whether your API key works in the request URL |
|
Supported symbols |
Whether your requested symbol is available in the free sandbox set |
|
Response shape |
Whether the endpoint returns bid, ask, size, volume, and timestamp fields |
|
Timestamp handling |
Whether your code can parse Unix millisecond timestamps |
|
Low-liquidity handling |
Whether your app handles empty, stale, or thin aftermarket responses |
|
Workflow fit |
Whether aftermarket quotes should be part of your dashboard, watchlist, or alerting tool |
For this endpoint, Basic/free access is symbol-limited, with support shown for AAPL, TSLA, AMZN, and 84 more supported symbols. The Basic plan is also best viewed as a testing environment, not a full production market data feed.
If your workflow needs broader symbol coverage, higher request volume, real-time access, scheduled polling, production dashboards, customer-facing monitoring, or institutional use, validate the endpoint with the free plan first. Then match the workflow to the plan, declaration requirements, and infrastructure needed for that scale.
Step 5: Use Aftermarket Quotes in a Workflow
Aftermarket quotes can be useful in watchlists, dashboards, post-earnings monitoring, and alerting tools. For example, a dashboard might show whether a stock is moving after an earnings release, whether the bid-ask spread is unusually wide, or whether quote activity looks thin after the close.
The key is to treat aftermarket quotes as context. After-hours trading can be less liquid than regular-session trading, and prices can move sharply on limited activity. A post-market quote can help explain what is happening after the close, but it should not be treated as a confirmed signal for the next day's open.
If you use aftermarket quote data inside a larger monitoring environment, build guardrails into the workflow:
- show the timestamp clearly
- identify when the response is delayed, stale, or empty
- display bid and ask separately instead of only showing a midpoint
- account for wider spreads and lower liquidity
- avoid treating thin after-hours moves as permanent valuation changes
- separate quote monitoring from trade execution logic
For teams building more complete market-data views, aftermarket quotes can sit beside regular-session market data, intraday bars, market movers, adjusted price history, and symbol-status checks.
Other Free API Workflows to Test
Once the aftermarket quote request is working, the same request-and-parse pattern can be reused across other FMP free API workflows. The goal is to test one endpoint at a time, inspect the response, and decide whether the data supports your product or research workflow.
Useful next tests include:
- Retrieve market movers, gainers, losers, and most active stocks when you want to compare regular-session activity with aftermarket movement.
- Handle delisted companies and historical symbols when you need your watchlist or alerting tool to avoid inactive tickers.
- Compare adjusted and unadjusted stock prices when you want to separate true price movement from split or dividend adjustments.
- Get stock intraday data with FMP APIs when you want to compare aftermarket quotes with regular-session intraday price behavior.
- Retrieve historical market capitalization when you want company-size context alongside quote movement.
Together, these pages create a practical sandbox path: test the aftermarket quote endpoint, compare it with regular-session data, add symbol-status handling, and then decide whether a larger market-monitoring workflow needs broader access.
When to Upgrade Beyond the Free Plan
A free API key is useful for testing endpoint behavior and building small prototypes. It is not always enough for a larger market-data workflow.
You may need to review a paid plan when your project requires:
- broader symbol coverage
- higher request volume
- more frequent polling
- real-time access
- scheduled refreshes
- production dashboards
- customer-facing monitoring
- institutional or commercial use
The free test should help you answer one question first: does the endpoint structure fit your workflow? If it does, the next step is matching plan access, usage limits, declaration requirements, and infrastructure to the scale you need. That may include estimating expected request volume before choosing a plan, comparing which FMP plan fits the workflow, or deciding whether the use case has moved beyond free-plan testing into an upgrade path.
FAQs
What does the Aftermarket Quote API return?
The endpoint returns aftermarket quote data for a requested symbol. The response can include symbol, bidSize, bidPrice, askSize, askPrice, volume, and timestamp.
Is the Aftermarket Quote API available on the free plan?
Yes. The Aftermarket Quote endpoint can be tested with a Basic/free API key for a supported symbol set. The plan view shows symbol-limited access, including AAPL, TSLA, AMZN, and 84 more supported symbols.
Is the data real time?
The endpoint is designed for aftermarket quote data, but users should review the access notes carefully. Nasdaq data is delayed by 15 minutes, and real-time access requires completing the user declaration form.
What can I actually test for free?
You can test authentication, request formatting, supported-symbol behavior, response structure, bid and ask fields, timestamp parsing, and how your app handles empty, stale, delayed, or low-liquidity responses.
Why do some symbols return empty or stale responses?
Some stocks have little or no active aftermarket activity. A symbol may return limited quote data if there are no active bid or ask updates, if the request is made outside the relevant session, or if the symbol is not available under the current access level.
Can I use aftermarket quotes for live monitoring?
A free API key is useful for testing the endpoint and building a small prototype. Broader monitoring, frequent polling, real-time access, production dashboards, or customer-facing workflows may require the appropriate paid plan, declaration requirements, and infrastructure.
Does FMP provide trade execution through this endpoint?
No. The Aftermarket Quote endpoint provides market data. It does not provide brokerage services, order routing, or trade execution.
Can aftermarket quote data predict the next trading day's open?
No. Aftermarket quotes can react to news, earnings, and other events, but they should not be treated as a reliable prediction of the next regular-session open. Liquidity is often thinner after hours, and prices can change before the next session begins.
