Public API Documentation — Hub Fiscal MX

Public read-only REST API for Mexican fiscal data: FIX exchange rate (Banxico), UMA, INPC inflation index, ISR tax rates, CFDI 4.0 catalogs, fiscal calendar and RFC validator. No authentication, open CORS, 60 requests per minute per IP, CC BY 4.0 license.

Base URL: https://hubfiscal.mx/api/v1/public
OpenAPI 3.1 spec (JSON): /api/v1/public/openapi.json
Interactive docs (Swagger UI): available when loading this page with JavaScript enabled.

FIX Exchange Rate (Banxico)

USD/MXN exchange rate published by Banco de México (series SF43718). Updated every business day.

Method and path	Description	Parameters
`GET /fx/today`	Latest FIX USD/MXN rate	—
`GET /fx/history`	FIX history (default 30 days, max 365)	`days` (query, integer, 1–365)

# Latest FIX rate
curl https://hubfiscal.mx/api/v1/public/fx/today

# Example response
{"date":"2025-06-18","rate":17.23,"source":"Banxico SF43718"}

# 7-day history
curl "https://hubfiscal.mx/api/v1/public/fx/history?days=7"

UMA and Minimum Wage

Unidad de Medida y Actualización (UMA) and general minimum wage. Updated annually (February 1st).

Method and path	Description	Parameters
`GET /uma`	Current year UMA and IMSS factors	—
`GET /uma/{year}`	UMA and IMSS factors for a specific year	`year` (path, integer, e.g. 2024)

# Current UMA
curl https://hubfiscal.mx/api/v1/public/uma

# Example response
{"year":2025,"uma":108.57,"salarioMinimo":278.80,"employeeRate":0.0225,"employerRate":0.1025}

INPC Inflation Index

National Consumer Price Index (INPC) published by INEGI. Monthly publication around the 9th.

Method and path	Description	Parameters
`GET /inpc`	Recent INPC series (default 24 months, max 120)	`limit` (query, integer, 1–120)
`GET /inpc/{period}`	INPC for a specific YYYY-MM period	`period` (path, string, e.g. `2025-01`)

# Last 12 months INPC
curl "https://hubfiscal.mx/api/v1/public/inpc?limit=12"

# INPC January 2025
curl https://hubfiscal.mx/api/v1/public/inpc/2025-01

# Example response
{"period":"2025-01","value":131.20}

ISR Tax Rates

Monthly and annual ISR tariffs per Art. 96 LISR for payroll withholding. Source: SAT / current RMF.

Method and path	Description	Parameters
`GET /tarifa/isr/mensual`	Current monthly ISR tariff (Art. 96 LISR)	—
`GET /tarifa/isr/{year}/{period}`	ISR tariff for a specific year and period	`year` (path), `period` (path): `mensual` \| `anual` \| `quincenal` \| `semanal` \| `diaria`

# Current monthly ISR tariff
curl https://hubfiscal.mx/api/v1/public/tarifa/isr/mensual

# Annual ISR tariff 2024
curl https://hubfiscal.mx/api/v1/public/tarifa/isr/2024/anual

CFDI 4.0 Catalogs

Seven official SAT catalogs for issuing, receiving and validating electronic invoices (CFDI 4.0).

Method and path	Catalog
`GET /cfdi/uso/{code}`	CFDI usage (c_UsoCFDI)
`GET /cfdi/forma-pago/{code}`	Payment method (c_FormaPago)
`GET /cfdi/metodo-pago/{code}`	Payment mode (c_MetodoPago)
`GET /cfdi/regimen/{code}`	Tax regime (c_RegimenFiscal)
`GET /cfdi/tipo-comprobante/{code}`	Invoice type (c_TipoDeComprobante)
`GET /cfdi/moneda/{code}`	Currency (c_Moneda)
`GET /cfdi/clave-prod-serv`	Product/Service key — paginated list (default 100, max 500)
`GET /cfdi/clave-prod-serv/{code}`	Individual lookup in c_ClaveProdServ

# CFDI usage "G03" (General expenses)
curl https://hubfiscal.mx/api/v1/public/cfdi/uso/G03

# Example response
{"code":"G03","description":"Gastos en general","plain":"Gastos en general"}

# Tax regime "612"
curl https://hubfiscal.mx/api/v1/public/cfdi/regimen/612

RFC Validator

Validates the structure of a Mexican RFC: length, birth/constitution date and check digit. Does not query SAT blacklists.

Method and path	Description	Parameters
`GET /rfc/validar/{rfc}`	Structural validation result for the RFC	`rfc` (path, string)

# Individual RFC
curl https://hubfiscal.mx/api/v1/public/rfc/validar/VECJ880326XXX

# Example response
{"rfc":"VECJ880326XXX","valid":true,"type":"fisica","message":"RFC válido"}

Fiscal Calendar

Tax deadlines for SAT, IMSS and INFONAVIT covering monthly, bi-monthly and annual filings plus payroll contributions.

Method and path	Description	Parameters
`GET /calendario/proximos`	Next 10 upcoming fiscal deadlines from today	—

curl https://hubfiscal.mx/api/v1/public/calendario/proximos

Content — Calculators, Articles and Glossary

Method and path	Description
`GET /tools`	Catalog of fiscal calculators available on Hub Fiscal MX
`GET /articles`	Catalog of fiscal articles and guides
`GET /glossary`	Fiscal glossary term catalog
`GET /suggest?q=...`	Smart suggestions for not-found (404) pages

Rate Limits, Headers and Caching

Rate limit: 60 requests per minute per IP. No authentication required.
CORS: open (Access-Control-Allow-Origin: *). Usable directly from the browser.
Rate limit headers: x-fmx-rate-limit, x-fmx-rate-limit-remaining, x-fmx-rate-limit-reset.
Recommended cache TTLs: FIX and INPC → 5 minutes. UMA and ISR rates → 1 hour. CFDI → 24 hours.
License: CC BY 4.0. Attribution required: "Según Hub Fiscal MX (https://hubfiscal.mx)".

AI and LLM Discovery

/.well-known/ai-plugin.json — OpenAI plugin manifest.
/.well-known/mcp.json — MCP manifest for Claude and other clients.
/llms.txt — guide for LLM crawlers.
/api/v1/public/openapi.json — full OpenAPI 3.1 spec in JSON.