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APIs and Realtime: System Design: Uncharted

Courses System DesignAPIs and Realtime

APIs and RealtimePro

Design stable contracts, scalable pagination, protected edges, webhooks, and live connection paths.

System Design
Unit 8 of 12
20 lessons
151 min
420 XP

This unit is part of Pro. Upgrade to open every lesson in it.

Lessons

20 total

1The Menu ContractDefine a stable API contract in terms of resource paths, request and response shapes, and actionable errors rather than internal implementation details.ProInteractiveConcept7 min20 XPOpen
2Resources and VerbsMap common collection and item operations to predictable HTTP method and resource-path combinations.ProInteractiveConcept7 min20 XPOpen
3Design the EndpointsDerive an endpoint contract from a user operation by naming the resource, method, request body, response, and error behavior in design order.ProInteractiveConcept7 min20 XPOpen
4Page Five ThousandExplain why deep offset pagination becomes expensive and can produce duplicate or missing items while an ordered feed changes.ProInteractiveConcept7 min20 XPOpen
5CursorsChoose an opaque cursor anchored to the last item’s ordering position so pagination can continue without a deep offset.ProInteractiveConcept7 min20 XPOpen
6Versioning Without TearsDistinguish compatible API additions from breaking contract changes that require a new version or migration window.ProInteractiveConcept7 min20 XPOpen
7Errors That HelpTranslate HTTP error responses into safe client actions such as correcting input, refreshing credentials, waiting, or retrying with backoff.ProInteractiveConcept7 min20 XPOpen
8The Rate LimiterExplain how a token bucket combines a bounded burst allowance with a steady sustainable refill rate.ProInteractiveConcept7 min20 XPOpen
9Napkin: Token BucketCalculate the tokens available after an idle period while applying the bucket capacity as an upper bound.ProInteractiveConcept7 min20 XPOpen
10Gate the Front DoorDesign an API edge that authenticates and rate-limits a user before distributing admitted requests across application services.ProDiagramConcept10 min20 XPOpen
11WebhooksExplain the reversed request direction of webhooks and assign bounded delivery retries to the event provider.ProInteractiveConcept7 min20 XPOpen
12Harden the WebhookHarden webhook processing with signature verification, a replay window, and idempotent handling of stable event identifiers.ProInteractiveConcept7 min20 XPOpen
13The Clingy ClientIdentify the request and connection waste created when many clients poll much more frequently than data changes.ProInteractiveConcept7 min20 XPOpen
14Three Ways to PushSelect long polling, server-sent events, or WebSockets based on update frequency and whether communication is one-way or two-way.ProInteractiveConcept7 min20 XPOpen
15Napkin: The Connection TaxEstimate aggregate gateway memory for idle realtime connections and express its scale as the nearest power of ten in decimal gigabytes.ProInteractiveConcept7 min20 XPOpen
16The Realtime PathDesign a realtime delivery path that hands client traffic from a socket gateway through a queue to a message service.ProDiagramConcept10 min20 XPOpen
17Read the p99Compare endpoint p99 latencies with a shared budget and identify the tail-latency violation.ProInteractiveConcept8 min20 XPOpen
18Public vs InternalExplain why unknown external consumers require longer API deprecation windows than coordinated internal clients.ProInteractiveConcept7 min20 XPOpen
19Explain CursorsExplain how cursor pagination reduces deep-scan work and page-boundary shifts without claiming that a changing feed is frozen.ProInteractiveConcept8 min20 XPOpen
20APIs and Realtime Mastery CheckEvaluate API and realtime designs for stable pagination, secure retry-safe webhooks, bounded bursts, and appropriate push semantics.ProInteractiveMastery check10 min40 XPOpen

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