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Technical diagrams that include the part a neat arrow often leaves out: what can still go wrong. Use three complete scenarios free, with source you can edit.
Light + dark SVG · Selectable native text · No signup · Built by Shruti
Illustrations for explanations, not executable infrastructure. Open a full-size SVG for small labels. All examples are synthetic.
Scenario 01
One event. Two deliveries.
An event receipt saved separately from a local mutation leaves a crash window. A unique event-ID receipt and the mutation can commit together; a replay can then skip a committed receipt.
Select the image to inspect native SVG text at full size. Light SVG · Dark SVGAssumptions and accessible description
Use a database-enforced unique event key; concurrent deliveries cannot both insert it.
Rollback both the receipt and mutation if the transaction fails. A committed receipt, not an in-memory flag, gates replays.
Distinct event IDs can represent the same business action. Define additional business keys when needed.
This does not make email, remote API calls or every downstream effect exactly once.
Alt description: Failure: event, mutation, crash before receipt, repeated mutation. Alternative: verify event, begin transaction, unique receipt with local mutation, commit and skip repeats.
Returning success before a durable handoff can lose work if the process crashes. Keep reception short, acknowledge only after accepted storage, and let a separate worker retry the retained item.
Select the image to inspect native SVG text at full size. Light SVG · Dark SVGAssumptions and accessible description
Use a durable queue or database, not a promise, process memory or an uncommitted write.
Provider timeouts and retry windows must be checked. An uncertain enqueue result can yield duplicates.
The worker needs its own deduplication, retry limits, failure visibility and side-effect policy.
Persist only approved payload data with suitable retention; this drawing is not a security checklist.
Alt description: Failure: verify event, acknowledge, lose in-memory work in a crash. Alternative: verify, durably store work, acknowledge acceptance and retry from storage.
A quoted CSV field can include a line break. The included tiny fixture has three physical lines but only a header and one data record. A line-based split is not a CSV parser.
Select the image to inspect native SVG text at full size. Light SVG · Dark SVGAssumptions and accessible description
Fixture bytes use CRLF, comma delimiter and double-quote enclosure. No trailing record newline is added.
Header is a parsed record but not a data row: two records here, one data row.
Other CSV dialects and encoding policies need explicit decisions; RFC 4180 is informational guidance.
Parsing does not certify business validity, safe spreadsheet execution or migration correctness.
Alt description: Failure: split a quoted CRLF into two rows and report a false mismatch. Alternative: choose dialect, parse quoting, retain the embedded break and validate actual records.
Technical reference: RFC 4180. Original artwork; no affiliation.
Original diagram pack available
The complete eight-scenario pack
Five additional scenes cover out-of-order events, transactional outbox, dead-letter review, composite export keys and related-fixture tokens. Sixteen light/dark SVGs, all editable definitions, renderer, captions, assumptions and synthetic fixtures.
Included
Free
Full pack
Original scenarios / SVGs
3 / 6
8 / 16
Matching JSON, renderer, captions
Yes
Yes
Synthetic fixtures
Quoted CSV
CSV + related JSON
Commercial document/teaching reuse
Under license
Under license
Full diagram pack: $7 USD through Payhip. No payments are collected on this preview site.
Where it helps
Use in an engineering lesson, README or failure-analysis article. Keep the assumptions beside the image and adapt the labels to your own system.
Free Mermaid, draw.io and D2 are strong alternatives when you prefer to draw your own. This pack offers original prepared explanations and layouts.
Limits before reuse
One database transaction cannot make every remote effect exactly once. Tokens do not certify anonymity. Browser SVG display is the target; Office/editor compatibility and fonts vary.
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What do I need to edit it?
A text editor and Node.js 22+ for the optional dependency-free JSON renderer. Viewing the included SVG/gallery needs only a modern browser. No paid API, database or hosted app is required.
Can I use these in paid teaching material?
The included license permits adaptation and embedding in your own commercial documents and courses. It prohibits redistributing the full source pack or a substantial standalone collection as a competing asset pack. Vendor material is not included.
