> ## Documentation Index > Fetch the complete documentation index at: https://developer.hayinsights.com/llms.txt > Use this file to discover all available pages before exploring further. # Vietnam FDI flows > Vietnam's inward FDI — registered and realized capital for the whole country, million USD. `series` holds the amount for each month on its own (derived as the difference between two consecutive year- to-date figures); the year-to-date figures the source publishes are in `registeredYtd` / `realizedYtd`. `cumulative` holds the year-to-date lines per year. `months` (12 / 36 / 60) only trims `series`. Missing months are null, never 0. ## OpenAPI ````yaml /openapi.yaml get /openapi/v1/macro/fdi/vn/flows openapi: 3.1.0 info: title: HayInsights Open API version: 0.1.0 description: > Programmatic access to the **HayInsights** financial-data hub — commodities, crypto, ETF, FX, macroeconomic, real-estate, news, economic-calendar and market-index datasets, served from a single API surface under `/openapi/v1/*`. This specification is the **single source of truth** for the public API surface — shared by SDK codegen, the reference docs, and (later) the mock server / contract tests. ## Authentication Every request must carry your API key in the `X-API-Key` header. There is a single authentication tier — no request signing. Create and manage keys in the HayInsights dashboard (Account → API keys). See **Authentication**. ## Plans & quota Access to each data domain and your request quota are governed by the subscription plan attached to your key. Each endpoint consumes a **weighted** amount of your per-minute quota; every response carries `X-RateLimit-*` headers. See **Rate limits** and **Plans & features**. contact: {} servers: - url: https://api-v2.hayinsights.com description: Production security: - HayInsightsApiKey: [] tags: - name: Commodities description: >- Spot prices, top movers, gold–DXY correlation and historical series for energy, metals and agricultural commodities. - name: Crypto description: >- Crypto market overview, dominance, bubble map, on-chain and derivatives metrics. - name: ETF description: >- Exchange-traded fund listings, performance & net-flow rankings, heatmap, holdings, NAV growth, fund composition and Bank of Japan ETF holdings. - name: FX description: >- Foreign-exchange summary, live table, 90-day correlation matrix and the emerging-market stress monitor. - name: Macro description: >- Macroeconomic indicators — GDP, CPI/PCE, exchange rates, population, central-government debt, policy rates / bond yields, interbank rates, FDI and trade by region. - name: Real Estate description: >- Land prices, transaction-level records, administrative geography (provinces / wards) and choropleth GeoJSON, by country. - name: News description: >- Market news headlines with per-article sentiment, plus an aggregate sentiment reading over a rolling window. - name: Calendar description: >- Economic calendar — rate decisions, CPI and GDP releases, market holidays and asset-level events. - name: Market description: >- Index snapshots and global index closes — levels and daily moves for S&P 500, Nasdaq, Nikkei, VN-Index and others. - name: Equities description: >- Japanese stock detail (Tokyo Stock Exchange) — end-of-day snapshot, corporate events, daily prices, financial statements and sector peers. paths: /openapi/v1/macro/fdi/vn/flows: get: tags: - Macro summary: Vietnam FDI flows description: > Vietnam's inward FDI — registered and realized capital for the whole country, million USD. `series` holds the amount for each month on its own (derived as the difference between two consecutive year- to-date figures); the year-to-date figures the source publishes are in `registeredYtd` / `realizedYtd`. `cumulative` holds the year-to-date lines per year. `months` (12 / 36 / 60) only trims `series`. Missing months are null, never 0. operationId: macroFdiVnFlows parameters: - name: months in: query required: false description: Months in `series` (1–60). schema: type: integer minimum: 1 maximum: 60 example: 12 - name: asOf in: query required: false description: >- Backtest: return exactly what the system knew at the end of that day (UTC), not later revisions by the source. Omit for the latest data. schema: type: string format: date example: '2026-09-01' responses: '200': description: Monthly and cumulative FDI into Vietnam. content: application/json: schema: $ref: '#/components/schemas/MacroFdiVnFlowsResponse' example: success: true statusCode: 200 data: country: vn unit: USD unitScale: 1000000 displayUnit: Million USD source: Ministry of Finance (FIA) latestPeriod: 2026-09 months: 2 from: 2026-08 to: 2026-09 series: - period: 2026-08 registered: 3120.5 realized: 2205 registeredYtd: 26389.8 realizedYtd: 16790 registeredYoy: 9.8 cutoffDay: 31 source: mof - period: 2026-09 registered: 2150.3 realized: 2010 registeredYtd: 28540.1 realizedYtd: 18800 registeredYoy: 12.4 cutoffDay: 30 source: mof cumulative: - year: 2026 registered: - 4330.1 - 6900.2 - 10980 realized: - 1510 - 3100 - 5410 meta: timestamp: '2026-10-16T04:00:00.000Z' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '404': $ref: '#/components/responses/NotFound' '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/InternalError' components: schemas: MacroFdiVnFlowsResponse: allOf: - $ref: '#/components/schemas/EnvelopeBase' - type: object required: - data properties: data: type: object required: - country - displayUnit - source - latestPeriod - series - cumulative properties: country: type: string description: Country code. example: vn unit: type: string description: Storage unit. example: USD unitScale: type: number example: 1000000 displayUnit: type: string description: Unit the values are expressed in. example: Million USD source: type: string description: Publisher. example: Ministry of Finance (FIA) sourceUrl: type: string description: Where the source publishes the data. latestPeriod: type: - string - 'null' description: Latest month with data (YYYY-MM). example: 2026-09 knowledgeAt: type: - string - 'null' description: When the system downloaded the source file. wasRestated: type: boolean example: false months: type: integer example: 12 from: type: - string - 'null' description: First month of `series`. example: 2025-10 to: type: - string - 'null' description: Last month of `series`. example: 2026-09 series: type: array items: type: object required: - period - registered - realized properties: period: type: string description: Month (YYYY-MM). example: 2026-09 registered: type: - number - 'null' description: Registered capital for the month. example: 2150.3 realized: type: - number - 'null' description: Realized capital for the month. example: 2010 registeredYtd: type: - number - 'null' description: Registered capital, year to date. example: 28540.1 realizedYtd: type: - number - 'null' description: Realized capital, year to date. example: 18800 registeredYoy: type: - number - 'null' description: >- Year-over-year change of registered capital, in percent. example: 12.4 cutoffDay: type: - integer - 'null' description: Day of month the source figure is cut off at. example: 30 source: type: string description: Publisher of this point. enum: - mof - nso example: mof cumulative: type: array items: type: object required: - year - registered - realized properties: year: type: integer example: 2026 registered: type: array items: type: - number - 'null' description: Year-to-date registered capital, January to December. realized: type: array items: type: - number - 'null' description: Year-to-date realized capital, January to December. seriesBreak: type: object description: >- Present when the source changed its method inside the window. properties: at: type: string description: Period where the break starts. example: 2014-Q1 reason: type: string description: Why the series is not comparable across the break. EnvelopeBase: type: object description: > Standard success envelope shared by every endpoint. Each operation's response wrapper extends this (via `allOf`) and adds a typed `data` property. required: - success - statusCode properties: success: type: boolean const: true description: Always `true` for a successful response. example: true statusCode: type: integer description: Mirrors the HTTP status code. example: 200 meta: $ref: '#/components/schemas/Meta' ErrorBody: type: object description: Standard error envelope returned for every 4xx / 5xx response. required: - success - statusCode - error properties: success: type: boolean const: false description: Always `false` for an error response. example: false statusCode: type: integer description: Mirrors the HTTP status code. example: 401 error: $ref: '#/components/schemas/ErrorDetail' meta: $ref: '#/components/schemas/Meta' Meta: type: object description: >- Response metadata. Always present; `timestamp` is the server time the response was generated. required: - timestamp properties: timestamp: type: string format: date-time description: Server time when the response was generated (ISO 8601). example: '2026-06-19T08:31:59.478Z' additionalProperties: true ErrorDetail: type: object description: Error detail object carried under `error` in the error envelope. required: - code - message properties: code: type: string description: > Machine-readable error code. Specific for authentication / quota errors (e.g. `API_KEY_REQUIRED`, `API_KEY_INVALID`, `FEATURE_NOT_IN_PLAN`, `RATE_LIMIT_EXCEEDED`). For validation (400) and not-found (404) the code is currently `INTERNAL_ERROR` and the HTTP status carries the semantics. example: API_KEY_INVALID message: description: Human-readable message, or a list of validation messages (400). oneOf: - type: string - type: array items: type: string example: Invalid API key responses: BadRequest: description: >- Invalid or missing parameter — bad enum, range, format, or a missing required query parameter. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 400 error: code: INTERNAL_ERROR message: - >- Invalid type parameter. Must be "gdp", "cpi", "pce", or "import-export" - Type parameter is required meta: error: Bad Request statusCode: 400 timestamp: '2026-06-19T08:34:08.081Z' Unauthorized: description: >- Missing, invalid, disabled or expired API key. Send a valid key in the `X-API-Key` header. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 401 error: code: API_KEY_INVALID message: Invalid API key meta: timestamp: '2026-06-19T08:34:08.023Z' Forbidden: description: >- Your subscription plan does not include this data feature, or your key's scope denies it. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 403 error: code: FEATURE_NOT_IN_PLAN message: Your plan does not include this feature meta: timestamp: '2026-06-19T08:34:08.100Z' NotFound: description: The requested resource was not found. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 404 error: code: INTERNAL_ERROR message: Commodity 'zzz-nope' not found meta: error: Not Found statusCode: 404 timestamp: '2026-06-19T08:34:08.205Z' RateLimited: description: > Rate limit exceeded — you have consumed your plan's per-minute weight budget. Wait until `X-RateLimit-Reset` (or `Retry-After` seconds) then retry. headers: X-RateLimit-Limit: $ref: '#/components/headers/XRateLimitLimit' X-RateLimit-Remaining: $ref: '#/components/headers/XRateLimitRemaining' X-RateLimit-Reset: $ref: '#/components/headers/XRateLimitReset' X-RateLimit-Weight-Used: $ref: '#/components/headers/XRateLimitWeightUsed' Retry-After: $ref: '#/components/headers/RetryAfter' content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 429 error: code: RATE_LIMIT_EXCEEDED message: Rate limit exceeded meta: timestamp: '2026-06-19T08:34:09.000Z' InternalError: description: Unexpected server error. Retry after a short exponential backoff. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 500 error: code: INTERNAL_ERROR message: Internal server error meta: timestamp: '2026-06-19T08:34:10.000Z' headers: XRateLimitLimit: description: Your plan's request-weight budget per 1-minute window. schema: type: integer example: 1000 XRateLimitRemaining: description: Remaining request weight in the current 1-minute window. schema: type: integer example: 997 XRateLimitReset: description: Unix timestamp (seconds) when the current rate-limit window resets. schema: type: integer format: int64 example: 1781857979 XRateLimitWeightUsed: description: Request weight consumed by this call (see each endpoint's weight). schema: type: integer example: 3 RetryAfter: description: Seconds to wait before retrying. Present on 429 responses. schema: type: integer example: 30 securitySchemes: HayInsightsApiKey: type: apiKey in: header name: X-API-Key description: > Your HayInsights API key (prefixed `apk_`). Create and manage keys in the HayInsights dashboard (Account → API keys). Send it in the `X-API-Key` header on **every** request to `/openapi/v1/*`. Which data domains you may access and your request quota are both governed by the subscription plan attached to the key — see the **Plans & features** and **Rate limits** guides. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.