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Before splitting frontend and backend work, agree on the smallest API contract that supports the demo’s main user flow. Put it in one shared artifact, give both sides the same realistic examples, and check an actual development response early. That keeps the team aligned without designing a speculative production platform.
Start with the demo flow, not the endpoint list
Sketch the screen or action the team wants to demonstrate. Identify the data it needs, what the user can submit, and what should happen when the operation succeeds or fails. Then define only the API operations needed for that path.
This is a practical way to keep a hackathon contract small: it is an editorial application of the consumer-visible contract principle, not a measured rule about hackathon outcomes. Leave out internal database details unless they affect what the client can observe.
Choose one shared contract
For an HTTP API, OpenAPI is a suitable shared contract. A shared typed interface can also work when everyone can use a compatible language and build environment. Choose based on what the team can read and check quickly, not on how elaborate the tooling looks.
#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
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| Boundary | Practical contract format |
|---|---|
| HTTP API | OpenAPI |
| Shared typed interface | Suitable when participants share a compatible language and build/runtime model |
| Events | AsyncAPI |
| RPC | Protocol Buffers |
| Standalone payload | JSON Schema |
Keep the artifact authoritative. If the route, field name, or response shape changes, update the contract and tell both sides before either implementation silently diverges. Name one person to coordinate edits; that person need not write every line.
Write down the behavior the client can see
For each operation in the demo flow, record the method and path, inputs, success response, errors the interface needs to handle, and any access-control requirement. State required and optional fields, types, null behavior, defaults, and allowed enum values where relevant.
Rank #2
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- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
- Request: path or query parameters and body fields, including which are required.
- Success: exact response field names and types, plus a representative value.
- Errors: status and response shape for outcomes the UI must distinguish.
- Access: whether an operation requires authentication or authorization, especially for private team data.
- Scope: agreed base path and whether the demo actually needs versioning.
For example, if the demo has a screen that lists a team’s projects, agree whether an empty list is a valid success, what each project object contains, and what the client receives when the user is not allowed to view that team’s data. Do not expose database table structure just because it exists.
Give both sides the same examples
Add a realistic example response to the contract. Include empty, loading, or error cases when they change what the interface must render. The exact states are a practical choice for the demo, not a requirement imposed by a specification format.
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Rank #3
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- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
The frontend can build against a mock derived from the contract while the backend implements the same interface. Entente documents generating consumer mocks from OpenAPI and replaying interactions against providers; that describes a workflow, not an independently established performance result (Entente documentation). An archived GitHub example likewise illustrates shared OpenAPI specifications, generated interfaces or clients, and runtime checks across services; treat it as an implementation example rather than a current tooling recommendation (OpenAPI Generator Petstore example).
Generated client types or server interfaces can reduce manual mismatches when the team’s stack supports them. If setup threatens to consume time needed for the demo, a shared schema, examples, and quick checks are enough to establish the boundary.
Rank #4
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- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
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- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Integrate against the real development API early
- Agree the user flow. Pick the screen or action to demonstrate and list the data it consumes.
- Write the contract. Define only the routes and behavior that flow needs, including errors and access requirements.
- Share one artifact and example. Make it easy for frontend and backend developers to find; discuss changes before changing names or shapes.
- Work in parallel. Build the frontend against a contract-derived mock while the backend implements the agreed interface.
- Connect one real screen early. Point it at the development API, compare the actual payload with the contract example, and fix discrepancies in the contract and implementation together.
A specification documents the agreement; it does not make the running server obey it. Check real responses rather than assuming the written contract guarantees runtime behavior. If data or actions are private, verify access controls on the server as well as the client-facing flow. For a discussion of contract contents and artifact choices, see ECC’s Contract-First Collaboration documentation.
Keep the agreement proportional
The contract should be precise about the demo boundary and deliberately limited beyond it. Do not spend the event modeling endpoints nobody plans to call, internal persistence, or production compatibility promises the team has not agreed to. Agree on versioning only if the demo needs it, and keep one shared place to resolve changes.
Quick Recap
Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
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