# Belfort Data API > Company figures extracted only from U.S. SEC filings, served by a read-only REST API and an MCP server. Every figure names the filing it came from. Instructions for agents: - Base URL: https://belfort-data-api.vercel.app - Send the API key in the `X-API-Key` header on every route except `/v1/status`. - Read the key from the `BELFORT_API_KEY` environment variable. Never ask the user to paste a key into the conversation, and never print, log or return it. - The OpenAPI 3.1 spec is at https://docs.belfortagent.xyz/openapi.json (YAML: https://docs.belfortagent.xyz/openapi.yaml). - Every figure carries its source filing (`source.accession` and `source.filing_url` on metrics, `accession` on document routes). When you quote a figure, cite that filing. - A blank in a filing is `null`, never 0. Do not treat `null` as zero. - Figures can change or disappear when a later filing arrives, and they are not versioned. Report `meta.as_of` with any figure you quote. - Unknown query parameters get HTTP 400. On 429 or 503, wait the seconds in `Retry-After` before trying again. - Paged routes return `meta.next_cursor`. Pass it as `cursor`, with the same filters, until it is null. - Measured error rates, and which fields are not measured yet: https://docs.belfortagent.xyz/quality.md. Known limits: https://docs.belfortagent.xyz/known-limits.md. - Source: U.S. Securities and Exchange Commission. Not affiliated with or endorsed by the SEC. This is data, not investment advice. ## Start here - [Belfort Data API](https://docs.belfortagent.xyz/index.md): Company figures from U.S. SEC filings. Every figure names the filing it came from, and the error rates are published. - [Quickstart](https://docs.belfortagent.xyz/quickstart.md): From an API key to your first answer, in curl, Python or TypeScript. - [Requests and responses](https://docs.belfortagent.xyz/requests-and-responses.md): Base URL, authentication, company IDs, the response envelope, errors, rate limits and paging. ## Datasets - [Datasets](https://docs.belfortagent.xyz/datasets.md): Every dataset the API serves, its route, its SEC or BLS source, and whether its error rate is published. - [Company](https://docs.belfortagent.xyz/datasets/company.md): One company by ticker or CIK, with its tickers, fiscal year end and how far back its data goes. - [Metrics](https://docs.belfortagent.xyz/datasets/metrics.md): Five headline figures as time series, each with its source filing, its first report and every adjustment. - [Financials](https://docs.belfortagent.xyz/datasets/financials.md): Normalized income statement, balance sheet and cash flow fields, read from the lines companies printed. - [Statements](https://docs.belfortagent.xyz/datasets/statements.md): Balance sheet, income, cash flow and comprehensive income statements as filed, one document per filing and statement. - [Segments](https://docs.belfortagent.xyz/datasets/segments.md): Revenue by product or service, by geography and by business segment, one axis at a time, from the filing's own tags. - [Insider trades](https://docs.belfortagent.xyz/datasets/insider-trades.md): Form 3, 4 and 5 transactions by a company's officers, directors and large holders, one row per transaction. - [Form 13F holdings](https://docs.belfortagent.xyz/datasets/form-13f.md): What an institutional investment manager reported holding on Form 13F, one row per holding. - [Holders](https://docs.belfortagent.xyz/datasets/holders.md): Which institutional managers reported holding a company on Form 13F, for one report period. - [Ownership](https://docs.belfortagent.xyz/datasets/ownership.md): Schedule 13D and 13G filings by a company's large shareholders, one record per reporting owner. - [Filings](https://docs.belfortagent.xyz/datasets/filings.md): Every filing a company made with the SEC, newest first, with links to EDGAR. - [Earnings releases](https://docs.belfortagent.xyz/datasets/earnings-releases.md): The press-release exhibit furnished with each 8-K that reports results, with its title and plain text. - [Macro](https://docs.belfortagent.xyz/datasets/macro.md): Two official U.S. series from the Bureau of Labor Statistics, CPI and unemployment, latest readings only. ## Trust the data - [Where the data comes from](https://docs.belfortagent.xyz/data-sources.md): The SEC and BLS sources behind each dataset, how a figure keeps its filing, and how fresh each dataset is. - [Quality](https://docs.belfortagent.xyz/quality.md): Measured error rates for each dataset, with sample sizes and methods. What we haven't measured yet is marked. - [Known limits](https://docs.belfortagent.xyz/known-limits.md): What the SEC sources can't give, what our rules decide imperfectly, and what we measured about both. ## Tools - [API reference (OpenAPI)](https://docs.belfortagent.xyz/openapi.json): every route, parameter and response field - [MCP server](https://docs.belfortagent.xyz/mcp.md): Give Claude Desktop, Claude Code or any MCP client read-only access to the API, with your key kept in an environment variable. ## Plans - [Pricing](https://docs.belfortagent.xyz/pricing.md): Plans and prices live on the Belfort website. During the pilot, keys are issued by Belfort. ## Optional - [All pages in one file](https://docs.belfortagent.xyz/llms-full.txt)