Postcodes.io 18.0.0

Version 18.0.0 is the most significant Postcodes.io update in years.13 New Fields and 2021 Census Data

Version 18.0.0 is the most significant Postcodes.io update in years. We've added 13 new geographic fields from the ONS Postcode Directory (ONSPD) and updated all census-based geographies to use 2021 Census boundaries.

New Fields

This release exposes geographic data that was previously only available through separate ONS datasets:

Healthcare Geographies

• NHS England Region – The high-level NHS administrative region (e.g., "London", "South East")

• Integrated Care Board – The NHS organisations responsible for planning healthcare services since 2022 (e.g., "NHS Kent and Medway Integrated Care Board")

• Cancer Alliance – Cancer care planning areas used by the NHS for coordinating cancer services

Economic Geographies

• Travel to Work Area – Zones where most residents both live and work. Useful for labour market analysis and commuting studies

• Local Enterprise Partnership (Primary and Secondary) – Business-led partnerships for economic development. Some postcodes fall within overlapping LEP areas

Environmental and Settlement Geographies

• National Park – Returns the National Park name if the postcode falls within one (e.g., "Peak District", "Lake District"), otherwise indicates the country with "(non-National Park)"

• Built-up Area – Urban settlement boundaries based on 2022 definitions

• Rural-Urban Classification (2011 and 2021) – Categories indicating the type of area, from "Urban major conurbation" to "Rural hamlet"

2021 Census Geographies

• Lower Layer Super Output Area (2021) – Small statistical areas typically containing 1,000-1,500 residents

• Middle Layer Super Output Area (2021) – Mid-size statistical areas typically containing 5,000-7,000 residents

• Output Area (2021) – The smallest census geography, typically containing 100-600 residents

All new fields include corresponding GSS codes for linking with official statistics.

2021 Census Update

The default Lower Layer Super Output Area and Middle Layer Super Output Area fields now return 2021 Census data instead of 2011. This is a breaking change if your application depends on 2011 boundaries.

2011 data remains available through dedicated alias fields for backwards compatibility.

Who Benefits From These Changes?

Public health researchers – Access NHS regions, Integrated Care Boards, and Cancer Alliances directly from postcode lookups. No need to cross-reference separate datasets.

Transport planners – Travel to Work Areas help analyse commuting patterns and labour market catchments.

Environmental analysts – Identify postcodes within National Parks, and use Rural-Urban Classification for urban/rural analysis.

Market researchers – Built-up Areas and Local Enterprise Partnerships provide economic context for demographic profiling.

Data scientists – The 2021 Census geographies align with the latest ONS statistical releases and deprivation indices.

Example Response

A postcode lookup for BR8 7RE now returns:

{
  "postcode": "BR8 7RE",
  "lsoa": "Sevenoaks 001A",                              // Lower Layer Super Output Area (2021)
  "msoa": "Sevenoaks 001",                               // Middle Layer Super Output Area (2021)
  "nhs_region": "South East",                            // NHS England Region
  "ttwa": "London",                                      // Travel to Work Area
  "national_park": "England (non-National Park)",        // National Park
  "bua": "Hextable",                                     // Built-up Area
  "icb": "NHS Kent and Medway Integrated Care Board",    // Integrated Care Board
  "cancer_alliance": "Kent and Medway",                  // Cancer Alliance
  "lsoa11": "Sevenoaks 001A",                            // Lower Layer Super Output Area (2011)
  "msoa11": "Sevenoaks 001",                             // Middle Layer Super Output Area (2011)
  "lsoa21": "Sevenoaks 001A",                            // Lower Layer Super Output Area (2021)
  "msoa21": "Sevenoaks 001",                             // Middle Layer Super Output Area (2021)
  "oa21": "E00124093",                                   // Output Area (2021)
  "ruc11": "(England/Wales) Urban major conurbation",    // Rural-Urban Classification (2011)
  "ruc21": "Urban: Nearer to a major town or city",      // Rural-Urban Classification (2021)
  "lep1": "South East",                                  // Local Enterprise Partnership (Primary)
  "lep2": null,                                          // Local Enterprise Partnership (Secondary)
  "codes": {
    "nhs_region": "E40000005",                           // NHS England Region GSS Code
    "ttwa": "E30000234",                                 // Travel to Work Area Code
    "national_park": "E65000001",                        // National Park GSS Code
    "bua": "E63012227",                                  // Built-up Area Code
    "icb": "E54000032",                                  // Integrated Care Board GSS Code
    "cancer_alliance": "E56000011",                      // Cancer Alliance GSS Code
    "lsoa11": "E01024445",                               // LSOA (2011) GSS Code
    "msoa11": "E02005087",                               // MSOA (2011) GSS Code
    "lsoa21": "E01024445",                               // LSOA (2021) GSS Code
    "msoa21": "E02005087",                               // MSOA (2021) GSS Code
    "oa21": "E00124093",                                 // Output Area (2021) Code
    "ruc11": "A1",                                       // Rural-Urban Classification (2011) Code
    "ruc21": "UN1",                                      // Rural-Urban Classification (2021) Code
    "lep1": "E37000056",                                 // LEP (Primary) GSS Code
    "lep2": null                                         // LEP (Secondary) GSS Code
  }
}

Migration Guide

If you need to maintain compatibility with 2011 Census boundaries, update your code to use the explicit 2011 alias fields (lsoa11, msoa11) instead of the default fields which now return 2021 data.

Additional Updates

• ONSPD November 2025 – Latest postcode data from ONS

• Terminated postcode data – 404 responses now include termination date for discontinued postcodes

Self-Hosting

If you self-host Postcodes.io, pull the latest Docker image. The database schema includes new lookup tables for all added fields. See the GitHub repository for upgrade instructions.

Summary

Postcodes.io 18.0.0 significantly expands the geographic context available for UK postcodes. Healthcare, economic, environmental, and census geographies are now available in a single API call, reducing the need to cross-reference multiple ONS datasets.

Questions? Reach out at support@ideal-postcodes.co.uk.