Start here

What do you need to do?

Pick the job in front of you. Each route takes you to the smallest useful set of guidance. Designer or researcher? Start with working with architects. Architect, or want to be one? See developing architecture at Defra.

Deliver

Deliver a service, phase by phase

The guardrails, artefacts and evidence you need in discovery, alpha, beta and live, with printable checklists.

Plan your phase

Decide

Check a design decision

Seven questions tell you whether your team can decide, needs advice, or should go to a design authority.

Start the check

Build

Find the guardrails

Search every Must, Should and Could by keyword, area or id, with the reason behind each one.

Open the library

Reuse

Find what already exists

Identity, payments, hosting, geospatial and more. Check the strategic option before you buy or build.

Browse capabilities

Onboard

Get onto Defra platforms

What the Core Delivery Platform, Defra ID, GOV.UK Notify, Pay and others give you, and how to get access.

See the platforms

Engage

Get architecture support

How the TGB, the TDA and solution design authorities work, what to bring and how quickly you get an answer.

See governance

How we decide

Doctrine, principles, guardrails

One line of sight from the draft DDTS doctrine to the decisions your team makes this week.

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DDTS doctrine

The draft non-negotiables, awaiting endorsement: platforms before projects, standards before exceptions, reuse before buy, data as an enterprise asset, assume AI, outcomes over structures, digital first.

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Architecture principles

How architecture applies the doctrine: delivery-focused, designed for users, maximum value, clean data, connected, secure, innovative, right tools.

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Guardrails

Practical Must, Should and Could defaults. Stay inside them and your team decides.

Light-touch governance

Most decisions belong to the team.

The closer a design stays to the guardrails and reuses what Defra already has, the lighter its governance. Boards look only at what is new, cross-cutting or outside the guardrails.

Check a decision How triage works

1. 01MapFind the business capability your service supports
2. 02ReuseUse the strategic technology options first
3. 03CheckTest the design against the guardrails and NFRs
4. 04DecideYour team, your SDA or the TDA, by risk
5. 05RecordWrite an ADR in the open so others can reuse it

The handrail

What Defra does

Every service should trace back to one of these business capabilities. Select one to see the technology that enables it and what you can reuse.

Core capabilities

01Act as a custodian of the environment and ecosystems02Conduct research and analyse evidence03Create policy and legislation04Engage with citizens and organisations05Issue licences and permits06Enforce compliance07Administer funds and grants08Respond to incidents and crises09Operate and deploy assets

Supporting capabilities

10Set organisational direction11Provide shared services

Explore the architecture

Connect business, data, applications and technology

Business

• Business capabilities
• Capability mapping
• Service patterns

Data

• Defra on a page
• Data standards
• Data guardrails

Applications

• APIs and integration
• Software development
• Coding standards

Technology

• Technology capabilities
• Hosting and platforms
• Choosing technology
• Non-functional requirements

Security

• Secure by Design
• Threat modelling
• Managing exceptions

Detailed guidance

Where the detail lives

This site sets direction and boundaries. For hands-on practice, go to the source.

• Defra software development standardsLanguages, coding, testing, source control and release practice
• Defra Digital Service ManualHow Defra designs, builds and assesses services
• Service StandardThe 14 points every government service meets
• Technology Code of PracticeHow government designs, builds and buys technology
• Secure by DesignGovernment's approach to security in delivery
• Secure by Design artefact libraryReusable security patterns, checklists and threat models

Working with us

Delivery partners welcome

Everything here is public, so you know what good looks like before you bid or start. Partners follow the same guardrails as Defra teams and can contribute to them.

What to expect from us, and what we expect from you

Help improve this site

Spotted a gap or something wrong? Open an issue or use the edit button on any page.

This site is in alpha. See the roadmap and what's new.