fourzerotwo-si

fourzerotwo-si Uk Postcodes API

UK Postcodes: Geocode and describe any UK postcode: coordinates, district, ward, constituency, region.

Documentation GitHub OpenAPI

Operations 8

GET /v1/uk-postcodes/lookup UK Postcodes: Postcode lookup #

GET /v1/uk-postcodes/nearest UK Postcodes: Nearest postcodes #

GET /v1/uk-postcodes/reverse UK Postcodes: Reverse geocode #

GET /v1/uk-postcodes/validate UK Postcodes: Validate postcode #

GET /v1/uk-postcodes/autocomplete UK Postcodes: Postcode autocomplete #

GET /v1/uk-postcodes/outcode UK Postcodes: Outward code #

GET /v1/uk-postcodes/terminated UK Postcodes: Terminated postcode #

GET /v1/uk-postcodes/places UK Postcodes: Place search #

Specifications

⚙

OpenAPI

https://artifacts.apis.io/fourzerotwo-si/openapi/fourzerotwo-si-uk-postcodes-api-openapi.yml

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this

find_apisBrowse and filter every API in the catalog.
get_api_artifactsOne API's artifacts, grouped by type.
get_openapiThe primary OpenAPI for this API.
find_similar_apisAPIs that look like this one.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This API

curl "https://apis.io/api/v1/apis/fourzerotwo-si:fourzerotwo-si-uk-postcodes-api"

All apis

curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

openapi: 3.2.0
info:
  title: Fourzerotwo Si Uk Postcodes API
  version: 1.1.0
  contact:
    url: https://fourzerotwo.si
  description: 'Operations tagged uk-postcodes across 2 of this provider''s published API definitions: openapi.json, fourzerotwo-si-openapi.json. Each path carries the servers of the definition it was published in.'
servers:
- url: https://fourzerotwo.si
tags:
- name: uk-postcodes
  description: 'UK Postcodes: Geocode and describe any UK postcode: coordinates, district, ward, constituency, region.'
paths:
  /v1/uk-postcodes/lookup:
    get:
      operationId: uk_postcodes__lookup
      summary: 'UK Postcodes: Postcode lookup'
      description: 'Full ONS record for one UK postcode, including latitude/longitude and administrative areas. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - uk-postcodes
      externalDocs:
        url: https://fourzerotwo.si/apis/uk-postcodes/lookup
      parameters:
      - name: postcode
        in: query
        required: true
        description: UK postcode, e.g. "SW1A 1AA"
        schema:
          type: string
          maxLength: 10
        example: SW1A 1AA
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: uk-postcodes__lookup
    servers:
    - url: https://fourzerotwo.si
  /v1/uk-postcodes/nearest:
    get:
      operationId: uk_postcodes__nearest
      summary: 'UK Postcodes: Nearest postcodes'
      description: 'Postcodes nearest to a given UK postcode. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - uk-postcodes
      externalDocs:
        url: https://fourzerotwo.si/apis/uk-postcodes/nearest
      parameters:
      - name: postcode
        in: query
        required: true
        description: UK postcode
        schema:
          type: string
          maxLength: 10
        example: SW1A 1AA
      - name: limit
        in: query
        required: false
        description: Max results (default 10)
        schema:
          type: integer
        example: 5
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: uk-postcodes__nearest
    servers:
    - url: https://fourzerotwo.si
  /v1/uk-postcodes/reverse:
    get:
      operationId: uk_postcodes__reverse
      summary: 'UK Postcodes: Reverse geocode'
      description: 'Nearest postcodes to a latitude/longitude. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - uk-postcodes
      externalDocs:
        url: https://fourzerotwo.si/apis/uk-postcodes/reverse
      parameters:
      - name: lat
        in: query
        required: true
        description: Latitude
        schema:
          type: string
        example: '51.501'
      - name: lon
        in: query
        required: true
        description: Longitude
        schema:
          type: string
        example: '-0.1416'
      - name: limit
        in: query
        required: false
        description: Max results
        schema:
          type: integer
        example: 3
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: uk-postcodes__reverse
    servers:
    - url: https://fourzerotwo.si
  /v1/uk-postcodes/validate:
    get:
      operationId: uk_postcodes__validate
      summary: 'UK Postcodes: Validate postcode'
      description: 'Whether a string is a valid, live UK postcode. Price: $0.001 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - uk-postcodes
      externalDocs:
        url: https://fourzerotwo.si/apis/uk-postcodes/validate
      parameters:
      - name: postcode
        in: query
        required: true
        description: UK postcode
        schema:
          type: string
          maxLength: 10
        example: SW1A 1AA
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.001000'
      x-free-tier: free
      x-mcp-tool: uk-postcodes__validate
    servers:
    - url: https://fourzerotwo.si
  /v1/uk-postcodes/autocomplete:
    get:
      operationId: uk_postcodes__autocomplete
      summary: 'UK Postcodes: Postcode autocomplete'
      description: 'Complete a partial UK postcode. Price: $0.001 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - uk-postcodes
      externalDocs:
        url: https://fourzerotwo.si/apis/uk-postcodes/autocomplete
      parameters:
      - name: postcode
        in: query
        required: true
        description: Partial postcode
        schema:
          type: string
          maxLength: 10
        example: SW1A 1
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.001000'
      x-free-tier: free
      x-mcp-tool: uk-postcodes__autocomplete
    servers:
    - url: https://fourzerotwo.si
  /v1/uk-postcodes/outcode:
    get:
      operationId: uk_postcodes__outcode
      summary: 'UK Postcodes: Outward code'
      description: 'Centroid and administrative areas for a postcode district (outward code), e.g. "SW1A". Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - uk-postcodes
      externalDocs:
        url: https://fourzerotwo.si/apis/uk-postcodes/outcode
      parameters:
      - name: outcode
        in: query
        required: true
        description: Outward code
        schema:
          type: string
          maxLength: 4
        example: SW1A
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: uk-postcodes__outcode
    servers:
    - url: https://fourzerotwo.si
  /v1/uk-postcodes/terminated:
    get:
      operationId: uk_postcodes__terminated
      summary: 'UK Postcodes: Terminated postcode'
      description: 'When a retired UK postcode was terminated, and where it was. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - uk-postcodes
      externalDocs:
        url: https://fourzerotwo.si/apis/uk-postcodes/terminated
      parameters:
      - name: postcode
        in: query
        required: true
        description: Retired postcode
        schema:
          type: string
          maxLength: 10
        example: CT9 1AA
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: uk-postcodes__terminated
    servers:
    - url: https://fourzerotwo.si
  /v1/uk-postcodes/places:
    get:
      operationId: uk_postcodes__places
      summary: 'UK Postcodes: Place search'
      description: 'Search UK places (towns, villages, suburbs) by name. Price: $0.002 USDC per call via x402. Free within the daily allowance with a free key.'
      tags:
      - uk-postcodes
      externalDocs:
        url: https://fourzerotwo.si/apis/uk-postcodes/places
      parameters:
      - name: q
        in: query
        required: true
        description: Place name
        schema:
          type: string
          maxLength: 80
        example: Margate
      - name: limit
        in: query
        required: false
        description: Max results
        schema:
          type: integer
        example: 5
      responses:
        '200':
          description: The data (paid, or free tier).
          content:
            application/json: {}
        '402':
          $ref: '#/components/responses/PaymentRequired'
        '400':
          $ref: '#/components/responses/Error'
        '404':
          $ref: '#/components/responses/Error'
        '502':
          $ref: '#/components/responses/Error'
      security:
      - {}
      - freeKey: []
      x-price-usd: '0.002000'
      x-free-tier: free
      x-mcp-tool: uk-postcodes__places
    servers:
    - url: https://fourzerotwo.si
components:
  responses:
    PaymentRequired:
      description: x402 payment required. The body (also base64 in the PAYMENT-REQUIRED header) lists accepted payments.
      headers:
        PAYMENT-REQUIRED:
          schema:
            type: string
          description: Base64 JSON x402 v2 PaymentRequired
      content:
        application/json:
          schema:
            type: object
            properties:
              x402Version:
                type: integer
              error:
                type: string
              accepts:
                type: array
                items:
                  type: object
    Error:
      description: 400 = invalid input, 404 = not found at the source, 502 = the source failed. Never charged.
      content:
        application/json:
          schema:
            type: object
            properties:
              error:
                type: string
              charged:
                type: boolean
  securitySchemes:
    freeKey:
      type: apiKey
      in: header
      name: X-API-Key
      description: Optional free key (fzt_…) for the free tier.
x-refined-from:
- openapi.json
- fourzerotwo-si-openapi.json