Bounded Context Canvas Template (DDD Crew)

Design one DDD bounded context: purpose, strategic classification, roles, inbound/outbound messages, language, rules, metrics

Kiến trúc & Thiết kế hệ thốngChuẩnBounded Context Canvas V5 (DDD Crew); Domain-Driven Design (Evans)CC BY-SA 4.0bounded context canvasCập nhật 20 thg 10, 2026

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Cách dùng: Use it when designing or reviewing a single bounded context, ideally in a workshop. Agree the name and purpose first, then fill communication and business decisions. The main pitfall is guessing: record unknowns as open questions instead.

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Bounded Context Canvas: [Context name]

Design record for a single bounded context: its name, purpose, strategic classification, domain roles, inbound and outbound communication, ubiquitous language, business decisions, assumptions, verification metrics and open questions. The sections follow the Bounded Context Canvas V5 by the DDD Crew (CC BY-SA 4.0), which builds on Domain-Driven Design as described by Eric Evans. Replace every [bracketed] value and every row marked Example. Worked examples use a parcel delivery company's "Shipment Scheduling" context.

Field	Value
Context name	[Shipment Scheduling]
Canvas version	[0.1]
Status	[Exploring / Agreed / Implemented / Under review]
Owning team	[@team-delivery-planning]
Domain / subdomain	[Last-mile delivery / Scheduling]
Workshop date	YYYY-MM-DD
Facilitator	[@facilitator]
Related documents	[Context map link], [EventStorming summary link], [ADR links]
Last updated	YYYY-MM-DD

1. Name

Name: [Shipment Scheduling]

Alternative names considered and rejected:

Candidate name	Why rejected
Example: Delivery Service	Technical name; says nothing about the responsibility
Example: Routing	Route optimisation is a separate, generic capability bought from a vendor
[Candidate]	[Reason]

2. Purpose

[Purpose statement. Example: Shipment Scheduling decides when each parcel will be delivered and commits that promise to the customer. It turns accepted shipments into delivery slots that respect depot capacity, driver shifts and customer preferences, and it re-plans when reality changes. Customers, merchants and depot planners rely on it for a delivery date they can trust.]

Key actors who get value: [Recipients, merchants, depot planners]

3. Strategic classification

Dimension	Options	Choice	Rationale
Domain importance	Core / Supporting / Generic	Example: Core	Reliable delivery promises are the main reason merchants choose us over competitors
Business model role	Revenue generator / Engagement creator / Compliance enforcer	Example: Revenue generator	Premium "named-day" delivery is sold per parcel
Evolution	Genesis / Custom built / Product / Commodity	Example: Custom built	Competitors build their own; no product fits depot-level capacity rules

Implication for investment: [Example: Build in-house with the most experienced team; buy route optimisation (generic) as a product.]

4. Domain roles

Role	Applies?	Evidence
Execution context	Example: Yes	Runs the scheduling workflow for each accepted shipment
Specification context	Example: Partly	Defines slot rules that Depot Operations follows
Analysis context	Example: No	Capacity forecasting lives in Network Planning
Gateway context	Example: No	Carrier integrations live in Partner Gateway
[Role]	[Yes / No / Partly]	[Evidence]

5. Inbound communication

ID	Collaborator	Collaborator type	Message	Message type	Relationship type	Notes
IN-01	Example: Shipment Intake	Bounded context	`ShipmentAccepted`	Event	Customer-supplier (we are downstream)	Triggers initial scheduling
IN-02	Example: Recipient web app	Frontend	`ChooseDeliveryDay`	Command	Owned UI	Recipient picks one of three offered days
IN-03	Example: Merchant portal	Frontend	`GetPromisedDate`	Query	Open host service	p95 latency 150 ms
IN-04	Example: Depot Operations	Bounded context	`DepotCapacityChanged`	Event	Partnership	Sent when a depot loses vans or staff
[IN-NN]	[Collaborator]	[Context / Frontend / External system / User]	[Message]	[Command / Query / Event]	[Relationship]	[Notes]

Use case swimlane (optional): describe the main flow as message in -> decisions made -> message out. Example: ShipmentAccepted -> choose earliest slot with capacity and promise rules -> DeliveryPromised.

6. Outbound communication

ID	Collaborator	Collaborator type	Message	Message type	Relationship type	Notes
OUT-01	Example: Notifications	Bounded context	`DeliveryPromised`	Event	Published language	Recipient receives SMS and email
OUT-02	Example: Route Optimisation (vendor)	External system	`OptimiseRoutes`	Command	Anticorruption layer	Nightly batch per depot
OUT-03	Example: Depot Operations	Bounded context	`DeliveryRescheduled`	Event	Partnership	Moves parcel to another van load
OUT-04	Example: Billing	Bounded context	`NamedDayServiceDelivered`	Event	Customer-supplier (we are upstream)	Charges the premium fee
[OUT-NN]	[Collaborator]	[Type]	[Message]	[Type]	[Relationship]	[Notes]

7. Ubiquitous language

Term	Meaning in this context
Example: Delivery promise	The date and time window the customer was told, which we commit to meet
Example: Slot	A depot's capacity for one day and one time window, measured in parcel stops
Example: Reschedule	Moving a promise to a new slot, with the recipient informed before the original window starts
Example: Named day	A paid service where the recipient chooses the day; failure triggers a refund
[Term]	[Meaning]

8. Business decisions

ID	Rule or policy	Source	Example
BR-01	Example: A slot may be booked up to 95% of its capacity; the last 5% is reserved for rescheduled parcels	Head of Operations	Depot with 400 stops accepts 380 new promises
BR-02	Example: A promise may be rescheduled at most twice before escalation to a planner	Customer service policy	Third reschedule creates a planner task
BR-03	Example: Named-day promises are never moved by automatic rescheduling	Commercial terms	Capacity loss moves standard parcels first
BR-04	Example: Promises are offered only for days when the recipient's address is serviceable	Network rules	Island postcodes receive Tuesday and Friday only
[BR-NN]	[Rule]	[Owner or document]	[Concrete example]

9. Assumptions

ID	Assumption	Impact if wrong	How we will validate	Status
AS-01	Example: Depot capacity changes at most a few times a day	Event volume and recalculation cost rise sharply	Count `DepotCapacityChanged` for four weeks	Open
AS-02	Example: Route optimisation remains a generic product we can buy	We would need a team to build it	Vendor review in Q3	Open
AS-03	Example: Recipients accept a promise window of two hours	Need finer slots and a new capacity model	Survey plus A/B test on 5% of traffic	Validated YYYY-MM-DD
[AS-NN]	[Assumption]	[Impact]	[Validation]	[Open / Validated / Invalidated]

10. Verification metrics

Metric	Source	Target	Current	Signal if breached
Example: Share of changes that also touch another context's code	Version control	< 10% of merged pull requests	[Value]	Boundary may be in the wrong place
Example: Synchronous calls to other contexts per scheduling command	Tracing	<= 2	[Value]	Context lacks data it should own
Example: Releases blocked by another team	Issue tracker	0 per month	[Value]	Coupling at team level
Example: Promises kept (delivered in promised window)	Production	>= 97%	[Value]	Business decisions or model need review
[Metric]	[Source]	[Target]	[Value]	[Signal]

11. Open questions

ID	Question	Owner	Needed by	Answer
OQ-01	Example: Should rescheduling for weather events be decided here or in Network Planning?	@domain-expert	YYYY-MM-DD	[Answer when known]
OQ-02	Example: Do merchants need to cancel a promise, or only the recipient?	@product-owner	YYYY-MM-DD	[Answer]
[OQ-NN]	[Question]	[@owner]	YYYY-MM-DD	[Answer]

12. Design review checklist

The purpose is written in business language and fits in four sentences.
Message names are coherent with each other and with the purpose.
Each message type is the right one (a command that should be an event, or the reverse, is flagged).
The interface is not too big: [N] distinct message types in, [N] out.
No message exposes internal model details that collaborators should not depend on.
No message obviously belongs to another context.
Every relationship type matches the context map.
Every assumption has a validation plan and every open question has an owner.

Standard and licence note

Structure adapted from the Bounded Context Canvas (V5) by the DDD Crew (Nick Tune and contributors), https://github.com/ddd-crew/bounded-context-canvas. The repository's licence file states Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0, https://creativecommons.org/licenses/by-sa/4.0/); its README shows a CC BY 4.0 badge, so this adaptation follows the stricter of the two. The adapted structure in this template is shared under CC BY-SA 4.0. Concepts of bounded contexts, ubiquitous language and context relationships come from Domain-Driven Design by Eric Evans. All explanatory text and examples are original to this collection.

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