Technical architect¶

The guardrails a technical architect leads, what to show in each phase, the patterns that help and when to work with an architect.

Prototype - testing with users

This section is an early prototype that we are testing with users. It may change a lot, and some of it may be wrong. Check with your solution design authority before relying on it, and tell us what works and what does not through the feedback link above.

You shape the design so that it stays inside the guardrails, reuses what exists and can change safely. You lead decisions on hosting, integration and technology choices, and record them.

You lead 32 guardrails, often with other roles. Leading means making sure the team meets them and can show it, not doing all the work. See them all in the guardrail library, filtered to your role.

Your guardrails, phase by phase¶

Discovery¶

Guardrail	Level	What to show
GR-AI-02 Use approved AI services and tenancies	Must	Any AI services you are exploring identified, with the Defra tenancy or enterprise agreement they would run under
GR-TECH-01 Look for something to reuse first	Must	Existing Defra and cross-government options for the need identified from the technology capability catalogue
GR-TECH-04 Assess SaaS before you adopt it	Must	SaaS and third-party products under consideration listed, with the assessments they will need
GR-HOST-01 Use Defra's strategic delivery platform by default	Must	Platform team engaged, and any hosting needs the Core Delivery Platform might not meet identified
GR-IAM-01 Use the strategic customer identity services	Must	Identity team engaged about the level of identity assurance needed and how users act for organisations
GR-AI-06 Talk to the TDA about novel use	Should	Novel or generative AI use in decision making identified, and a conversation with the Technical Design Authority booked
GR-TECH-02 Buy commodity, build differentiating	Should	Buy or build options appraisal in the ADR or business case
GR-FE-04 Consider forms platforms first	Should	ADR noting whether the forms capability was considered
GR-DEV-09 Record significant decisions as ADRs	Should	ADR log in the repository or linked from its README
GR-SUS-01 Consider sustainability in design decisions	Should	Environmental impact recorded in ADRs for hosting and technology choices
GR-FIELD-04 Check connectivity before you design	Could	Connectivity in the places the service will be used checked, and the approach recorded

Alpha¶

Guardrail	Level	What to show
GR-AI-02 Use approved AI services and tenancies	Must	AI services chosen for the design, each confirmed as running in a Defra tenancy or under an approved agreement
GR-TECH-01 Look for something to reuse first	Must	ADR recording the reuse options considered and why they did or did not fit
GR-TECH-04 Assess SaaS before you adopt it	Must	Security, data protection, data location, accessibility and single sign-on assessed before contract
GR-HOST-01 Use Defra's strategic delivery platform by default	Must	The design runs on the Core Delivery Platform, or an exception has been requested
GR-IAM-01 Use the strategic customer identity services	Must	Sign-in designed with Defra Customer Identity, and tested with users
GR-AI-06 Talk to the TDA about novel use	Should	Technical Design Authority review outcome recorded in the ADR
GR-AI-08 Give agents the least privilege they need	Should	Each agent's tools and permissions listed in the design, with a workload identity for the agent
GR-AI-09 Get human approval for consequential actions	Should	Agent actions classified, and the actions that need human approval identified in the design
GR-API-01 API first	Should	API specification written before or alongside the user interface
GR-API-03 Follow government API standards	Should	API design reviewed against the GDS API technical and data standards
GR-API-05 No integration through shared databases	Should	Container diagram showing integration only through APIs, events or governed data products
GR-API-06 Use events for change notifications	Should	Event and message definitions described in AsyncAPI
GR-TECH-02 Buy commodity, build differentiating	Should	Buy or build options appraisal in the ADR or business case
GR-TECH-03 Plan your exit before you enter	Should	Draft exit plan for each new product, platform or significant supplier
GR-TECH-05 Prefer open standards and portable technology	Should	ADR noting the open standards used and how portable the choice is
GR-FE-04 Consider forms platforms first	Should	ADR noting whether the forms capability was considered
GR-HOST-02 Public cloud first	Should	Where the platform cannot be used, the hosting design uses a Defra-managed public cloud tenancy
GR-HOST-04 Use managed services before self-managed	Should	Hosting design listing the managed services used
GR-HOST-06 Host data in the UK	Should	Hosting design places every data store and backup in UK regions
GR-HOST-07 Design for the resilience the service needs	Should	Recovery time and recovery point objectives agreed with the service owner, and a design that meets them
GR-IAM-04 Separate authentication from authorisation	Should	Authorisation rules written down and covered by automated tests
GR-PROD-03 Contribute to platforms rather than working around them	Should	Requests and contributions raised with platform teams, and ADRs where the team worked around a platform
GR-DEV-01 Use the supported languages and frameworks	Should	ADR recording the reason wherever the service uses a different stack
GR-DEV-09 Record significant decisions as ADRs	Should	ADR log in the repository or linked from its README
GR-SUS-01 Consider sustainability in design decisions	Should	Environmental impact recorded in ADRs for hosting and technology choices
GR-FIELD-04 Check connectivity before you design	Could	Connectivity in the places the service will be used checked, and the approach recorded
GR-SUS-03 Choose lower-carbon regions and services	Could	Region and service choice recorded with its carbon intensity

Beta¶

Guardrail	Level	What to show
GR-AI-02 Use approved AI services and tenancies	Must	The AI services in the built service run only in approved tenancies, shown in the hosting design and configuration
GR-HOST-01 Use Defra's strategic delivery platform by default	Must	The service runs on the Core Delivery Platform, or under an approved exception
GR-IAM-01 Use the strategic customer identity services	Must	Integration with Defra Customer Identity built and tested
GR-IAM-02 Staff sign in with Microsoft Entra ID	Must	Staff sign in through Microsoft Entra ID with multi-factor authentication, and there are no local staff accounts
GR-AI-08 Give agents the least privilege they need	Should	Agent permissions configured as designed and tested, including that the agent cannot reach tools it should not
GR-AI-09 Get human approval for consequential actions	Should	Approval enforced in the tool layer, with tests showing the agent cannot act without it
GR-API-01 API first	Should	API specification written before or alongside the user interface
GR-API-03 Follow government API standards	Should	API design reviewed against the GDS API technical and data standards
GR-API-04 Version and deprecate deliberately	Should	Versioning approach published for each API and event
GR-API-05 No integration through shared databases	Should	Built integrations match the container diagram, with no access to another service's database
GR-API-06 Use events for change notifications	Should	Event and message definitions described in AsyncAPI
GR-API-08 Make APIs discoverable	Should	Entry in the platform API catalogue
GR-TECH-03 Plan your exit before you enter	Should	Exit plan agreed, with contracts giving Defra its data and the right to export it in open formats
GR-HOST-02 Public cloud first	Should	The service runs in a Defra-managed public cloud tenancy
GR-HOST-04 Use managed services before self-managed	Should	Hosting design listing the managed services used
GR-HOST-06 Host data in the UK	Should	Data location confirmed for every data store and backup as built
GR-HOST-07 Design for the resilience the service needs	Should	Multi-zone design built, and recovery tested before go-live
GR-IAM-04 Separate authentication from authorisation	Should	Authorisation rules written down and covered by automated tests
GR-OPS-03 Define and measure service levels	Should	Agreed service level objectives with monitoring and alerts
GR-PROD-03 Contribute to platforms rather than working around them	Should	Requests and contributions raised with platform teams, and ADRs where the team worked around a platform
GR-DEV-09 Record significant decisions as ADRs	Should	ADR log in the repository or linked from its README

Live¶

Guardrail	Level	What to show
GR-AI-02 Use approved AI services and tenancies	Must	List of AI services in use, reviewed when services or agreements change
GR-HOST-01 Use Defra's strategic delivery platform by default	Must	The service still runs on the platform, and any exception is reviewed before it expires
GR-IAM-01 Use the strategic customer identity services	Must	No other sign-in introduced
GR-IAM-02 Staff sign in with Microsoft Entra ID	Must	Staff access reviewed regularly through Entra ID groups
GR-AI-08 Give agents the least privilege they need	Should	Agent permissions reviewed regularly, as for a privileged user
GR-AI-09 Get human approval for consequential actions	Should	Approval records reviewed, and the classification updated when the agent gains new tools
GR-API-03 Follow government API standards	Should	API design reviewed against the GDS API technical and data standards
GR-API-04 Version and deprecate deliberately	Should	Deprecation notices sent to consumers and retirement dates published for old versions
GR-API-05 No integration through shared databases	Should	Integrations reviewed when the service or its dependencies change
GR-API-08 Make APIs discoverable	Should	Entry in the platform API catalogue
GR-TECH-03 Plan your exit before you enter	Should	Exit plan reviewed at contract renewal, with switching cost estimated
GR-HOST-02 Public cloud first	Should	No on-premises hosting introduced
GR-HOST-06 Host data in the UK	Should	Data location checked when new stores or services are added
GR-HOST-07 Design for the resilience the service needs	Should	Recovery tested at least once a year, with the date of the last test
GR-OPS-03 Define and measure service levels	Should	Agreed service level objectives with monitoring and alerts
GR-PROD-03 Contribute to platforms rather than working around them	Should	Requests and contributions raised with platform teams, and ADRs where the team worked around a platform
GR-DEV-09 Record significant decisions as ADRs	Should	ADR log in the repository or linked from its README
GR-SUS-05 Measure and report	Could	Carbon footprint reported alongside cost

Significant change¶

Guardrail	Level	What to show
GR-TECH-01 Look for something to reuse first	Must	ADR showing reuse options considered for any new component
GR-API-04 Version and deprecate deliberately	Should	Consumers told about breaking changes in advance, with a new version and a retirement date for the old one
GR-DEV-09 Record significant decisions as ADRs	Should	ADR log in the repository or linked from its README
GR-TECH-03 Plan your exit before you enter	Should	Exit plan updated for any new product or supplier
GR-AI-06 Talk to the TDA about novel use	Should	Technical Design Authority review of any new AI use introduced by the change
GR-HOST-07 Design for the resilience the service needs	Should	Recovery objectives and design checked for the change

Retire a service¶

Guardrail	Level	What to show
GR-API-04 Version and deprecate deliberately	Should	Consumers told the retirement date in advance, and moved to a replacement
GR-TECH-03 Plan your exit before you enter	Should	Exit plan carried out - data exported in open formats and contracts ended

Patterns that help¶

Acting on behalf of an organisation or holding - Users act for a business, a land holding or another person, and the service must check they are allowed to.
Asynchronous submission with an outbox - A user submits something that other systems must process, and you do not want those systems' availability to block the user.
Reading from an authoritative source - A service needs shared data - customers, organisations, holdings, locations or species - that another part of Defra owns.
File upload with malware scanning - Users upload documents or images, and the files must be scanned and stored safely before anyone opens them.

Working with architects¶

Take novel or cross-cutting designs to the Technical Design Authority.
Keep the ADR log and C4 diagrams current through every phase.