Company financials API: five checks before you build on one

Before you build on a company financials API, check five things: that every figure carries its fiscal period and end date, says whether a quarter is discrete or year-to-date, names the filing it came from, states its unit and currency in full, and links to its source concept or page. An API that misses any of these will put silent errors into your models.

We hold our own Data API, which serves US and Nordic company figures, to the same five checks. This article walks through each one using Microsoft Corporation (Nasdaq: MSFT) and its fiscal 2026 quarters as the worked example.

Check 1: the period is the company's fiscal period, with an end date

Microsoft's fiscal year ends on 30 June. Its Q1 FY2026 is the quarter ended 30 September 2025, and FY2026 ended on 30 June 2026. A label such as "Q1 2026" without an end date is ambiguous: a calendar-year reader takes it as January to March 2026, which is Microsoft's Q3.

What to check: every figure should come with its period end date, and ideally its start date, next to the fiscal label. When you compare companies with different year ends, align them on end dates, not labels.

Check 2: discrete quarters versus year-to-date figures

US 10-Q filings present the income statement for the three months and for the year to date, and the cash flow statement usually for the year to date only. The 10-K covers the full year with no separate fourth-quarter column, so a fourth quarter is the full year minus the first three quarters.

What to check: does the API say whether a quarterly figure was reported for the quarter alone or derived? In our data, Microsoft's Q4 figures carry a derived flag and the formula used, while Q1 to Q3 are marked as reported standalone values from Microsoft's 10-Q filings.

The table below shows Microsoft's last five fiscal quarters with the period end date and the basis of each figure.

Source: Microsoft Corporation Forms 10-Q and 10-K, fiscal 2025 and 2026, quarterly data. Q4 = full year minus Q1 to Q3.¹²

Full-year FY2026 revenue in the same data is USD 331,839 million. If an API returns cumulative figures under a "quarter" label, every quarter-on-quarter chart built on it is wrong.

Check 3: restatements and the filing each figure comes from

Companies restate. A later filing can present the prior year differently after a reclassification, a discontinued operation or an accounting change, so the question is which version an API gives you.

In our data, Microsoft's FY2025 figures (revenue USD 281,724 million, net income USD 101,832 million) carry two references: the FY2025 10-K as the original filing, and the FY2026 10-K, which presents FY2025 as its comparative year and is the version we show. What to check: does each figure carry the accession number or document it was taken from, so you can tell an original value from a comparative in a later report?

Check 4: units, scale and currency stated in full

Filings print figures in thousands or millions; an API should not leave the scale implicit. We return values in full units with the unit attached: Microsoft's Q4 FY2026 revenue is 90,007,000,000 with the unit USD, and diluted EPS is in USD per share. Nordic companies usually report in EUR or SEK, and we do not convert figures between currencies.

What to check: is the currency stated per figure, is the scale explicit, and does the API convert currencies silently? To compare a EUR reporter with a USD reporter, compare ratios or state each currency.

Check 5: source links and mapping to an accounting standard

A figure you cannot trace is a figure you cannot defend in a review. For US companies, each value in our data carries the XBRL concept it was read from (Microsoft revenue: RevenueFromContractWithCustomerExcludingAssessedTax; operating income: OperatingIncomeLoss) and a link to the SEC filing. For Nordic companies, figures carry the IFRS concept from the ESEF filing or a link to the report page.

Mapping matters because companies tag the same idea with different concepts. Revenue can sit under several US GAAP tags depending on company and year, while IFRS reporters use ifrs-full:Revenue. What to check: does the API show which concept it mapped to each standard field?

How a request to the Clarifo company financials API looks

Our Data API is standard REST with JSON responses and an OpenAPI spec. To get a key, open Settings, go to API Keys & Usage and choose Create API Key. Keys start with clf_ and are sent as a bearer token; use a test key for development and a live key for production. All keys share one account quota.

A request for one company's figures for a fiscal year and quarter looks like this:

GET /api/v1/data/companies/AAPL/financials?year=2025&quarter=3

The year and quarter are the company's own fiscal year and quarter, which is Check 1 again. For text, /api/v1/data/filings/content-search searches the full text of filings. You can also compare up to five companies or rank a market by growth or size. Parameters and response fields are in our API docs.

The same data works without code through our MCP server, a built-in app in Claude and ChatGPT; see how to use Clarifo in Claude for company research. A prompt that runs Checks 1 and 2 for you: