> ## Documentation Index > Fetch the complete documentation index at: https://docs.financialdatasets.ai/llms.txt > Use this file to discover all available pages before exploring further. # Historical > Get monthly US consumer price index history since 1947: headline and core CPI plus food, energy, shelter, and services, with month-over-month and year-over-year changes. ### Overview The Inflation API lets you pull the monthly US Consumer Price Index (CPI) for one series at a time, from 1947 to today, with the month-over-month and year-over-year percent changes computed for you. We source the data directly from authoritative government sources. Values are index levels (1982-84 = 100); the changes are percentages. To get started, please create an account and grab your API key at [financialdatasets.ai](https://financialdatasets.ai). You will use the API key to authenticate your API requests. ### Coverage | History | Series | Updated | | ------------- | ------ | ------- | | 1947 to today | 12 | Monthly | ### Series Six concepts, each seasonally adjusted (`_sa`) and not seasonally adjusted (`_nsa`): | Series | What it is | From | | ------------------------------------------------------------- | ------------------------------ | --------------------- | | `cpi_all_sa`, `cpi_all_nsa` | All items | 1947 | | `cpi_core_sa`, `cpi_core_nsa` | All items less food and energy | 1957 | | `cpi_food_sa`, `cpi_food_nsa` | Food | 1947 | | `cpi_energy_sa`, `cpi_energy_nsa` | Energy | 1957 | | `cpi_shelter_sa`, `cpi_shelter_nsa` | Shelter | 1953 | | `cpi_services_less_energy_sa`, `cpi_services_less_energy_nsa` | Services less energy services | 1957 (NSA), 1967 (SA) | You can fetch this list, with each series' first available month, with a free `GET` request to: [https://api.financialdatasets.ai/macro/inflation/series/](https://api.financialdatasets.ai/macro/inflation/series/) ### Reading the fields * `date` is the reference month as its first day: `2026-08-01` is the August 2026 print, which is published in mid September. It is not the release date. * `value` is the published index level. * `change_1m_pct` is the percent change from the prior month and `change_12m_pct` from the same month a year earlier, both rounded to one decimal. The headline "inflation rate" is `change_12m_pct` of `cpi_all_nsa`; the headline monthly figure is `change_1m_pct` of `cpi_all_sa`. * A field is `null` when the comparison month was not published. October 2025 is `null` in every series because no October 2025 CPI was published, so the November 2025 1-month change and the October 2026 12-month change are `null` too. * History is the latest published values. When a past month is revised, the stored value is replaced. ### Getting Started There are only 3 steps for making a successful API call: 1. Add your API key to the header of the request as `X-API-KEY`. 2. Add the `series` parameter, which is required. Optionally add `start_date` and `end_date` (inclusive, `YYYY-MM-DD`; any day inside a month selects that month). With no dates you get the trailing five years. 3. Execute the API request. Rows come newest first in pages of up to 10. When more rows remain, the response includes a `next_page_url`; request it as-is to get the next page. See the [pagination guide](/guides/pagination). ### Example ```python Inflation theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} import requests # add your API key to the headers headers = { "X-API-KEY": "your_api_key_here" } # set parameters series = 'cpi_all_sa' # required start_date = '2025-09-01' # optional end_date = '2026-08-31' # optional # create the URL with parameters url = ( f'https://api.financialdatasets.ai/macro/inflation' f'?series={series}' f'&start_date={start_date}' f'&end_date={end_date}' ) # make API request response = requests.get(url, headers=headers) # parse the observations from the response inflation = response.json().get('inflation') ``` ### Example Response ```json theme={"theme":{"light":"vitesse-light","dark":"vitesse-dark"}} { "inflation": [ { "series": "cpi_all_sa", "date": "2026-08-01", "value": 334.131, "change_1m_pct": 0.4, "change_12m_pct": 3.4 } ] } ``` ## OpenAPI ````yaml GET /macro/inflation openapi: 3.0.1 info: title: Financial Datasets API description: >- Stock market API with real-time and historical financial data for 27,000+ tickers over 30+ years. Financial statements, equity prices, insider trades, SEC filings, and more. version: 1.0.0 license: name: MIT url: https://opensource.org/licenses/MIT contact: name: API Support url: mailto:support@financialdatasets.ai email: support@financialdatasets.ai termsOfService: https://financialdatasets.ai/terms-of-use servers: - url: https://api.financialdatasets.ai/ description: Production server security: - X-API-KEY: [] tags: - name: Financial Statements description: Access to income statements, balance sheets, and cash flow statements - name: Market Data description: Real-time and historical price data - name: Company Information description: Company facts like ticker, name, and description - name: Earnings description: Earnings data and related information - name: News description: Real-time and historical news articles - name: SEC Filings description: SEC filings and regulatory documents - name: Insider Trades description: Insider trading activity and transactions - name: Activist Ownership description: Activist stakes from SEC Schedule 13D filings, in real time - name: Beneficial Ownership description: >- Holders of more than 5% of a company's shares, from SEC Schedules 13D and 13G - name: Insider Ownership description: Insider ownership statements from SEC Forms 3 and 5 - name: Institutional Holdings description: SEC-direct 13F equity holdings of institutional investment managers - name: IPOs description: >- Upcoming IPOs from SEC registration statements (Form S-1), with extracted pre-IPO financial statements - name: Index Funds description: >- ETF and index-fund holdings, weights, and the funds that hold a given security - name: Financial Metrics description: Financial ratios, metrics, and key performance indicators - name: Macroeconomics description: Real-time and historical macroeconomic data like interest rates - name: KPIs description: Sector-specific operational KPIs extracted from earnings releases. - name: Agent Account description: Self-serve account creation and funding for AI agents. paths: /macro/inflation: get: tags: - Macroeconomics summary: Inflation (Historical) description: >- Monthly US Consumer Price Index history for one series, newest first, with the month-over-month and year-over-year percent changes. Dates are reference months (first day of the month). Values are index levels (1982-84 = 100), sourced from authoritative government sources. A change is null when the comparison month was not published. operationId: getInflation parameters: - name: series in: query description: >- The series id, e.g. cpi_all_sa. Six concepts (all items, core, food, energy, shelter, services less energy), each seasonally adjusted (_sa) and not (_nsa). Use the /macro/inflation/series endpoint to get the list. required: true schema: type: string - name: start_date in: query description: >- The first month to return, inclusive, in YYYY-MM-DD format; any day inside a month selects that month. Defaults to five years before end_date when both dates are omitted; omit it with an end_date to get all available history through that month. required: false schema: type: string - name: end_date in: query description: >- The last month to return, inclusive, in YYYY-MM-DD format. Defaults to today. required: false schema: type: string - name: cursor in: query description: >- Opaque pagination cursor from a previous response's next_page_url. When provided, all other query parameters are ignored: the cursor carries the original request's filters. Treat it as opaque; do not construct or modify it. required: false schema: type: string responses: '200': description: Inflation response content: application/json: schema: $ref: '#/components/schemas/InflationResponse' '400': $ref: '#/components/responses/BadRequestError' '401': $ref: '#/components/responses/UnauthorizedError' '402': $ref: '#/components/responses/PaymentRequiredError' '404': $ref: '#/components/responses/NotFoundError' components: schemas: InflationResponse: type: object properties: inflation: type: array items: $ref: '#/components/schemas/InflationObservation' next_page_url: type: string description: >- Absolute URL of the next page of results. Present only when more results remain; request it as-is to continue. Each page holds up to 10 records. InflationObservation: type: object properties: series: type: string description: The series id, e.g. cpi_all_sa. date: type: string description: >- The reference month as its first day in YYYY-MM-DD format, e.g. 2026-08-01 for August 2026. Not the release date. value: type: number nullable: true description: >- The published index level (1982-84 = 100). Null when the month was not published. change_1m_pct: type: number nullable: true description: >- Percent change from the prior month, rounded to one decimal. Null when either month was not published. change_12m_pct: type: number nullable: true description: >- Percent change from the same month a year earlier, rounded to one decimal. Null when either month was not published. For cpi_all_nsa this is the headline inflation rate. ErrorResponse: type: object properties: error: type: string description: A short error message. message: type: string description: A more detailed error message. responses: BadRequestError: description: Bad request content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: Bad Request message: Invalid request parameters UnauthorizedError: description: Unauthorized content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: Unauthorized message: Invalid API key provided PaymentRequiredError: description: The request requires a paid subscription content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: Payment Required message: >- This endpoint requires a paid subscription. Please upgrade your plan. NotFoundError: description: The specified resource was not found content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: error: Not Found message: Ticker XXXX not found securitySchemes: X-API-KEY: type: apiKey name: X-API-KEY description: API key for authentication. in: header ````