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3. AI Model Inference API Gateway Category: Backend Development / API Engineering Budget: £1,350 GBP — Fixed Price, 3 Milestones Project deadline: Saturday, 10 October 2026 Description: We're building a backend gateway that sits in front of one or more machine learning models and exposes them as a clean, versioned inference API. The gateway needs to handle request queuing under load, model version routing, response caching where appropriate, and consistent error handling when a model fails to return a result. This is a pure backend/API service — no UI work involved. Key requirements: • Strong backend/API development skills (Python, Java, or C#) • Experience serving ML models via API (e.g. FastAPI, TorchServe, Triton, or similar) • Comfortable working with request queuing and rate-limiting under load • Solid testing discipline for API and pipeline reliability Deliverables: • Working inference API endpoint(s) with versioned model routing • Request queuing/rate-limiting and error-handling logic • Test suite covering standard and edge-case inputs Payment Structure — £1,350 GBP Fixed, 3 Milestones Milestone 1 – Advance Payment: £540 • Paid upon project commencement and award of contract • Funds initial development and setup of the agreed scope • This payment does not constitute delivery, acceptance, or completion of any part of the work, and does not waive any requirement of this posting Milestone 2 – Advance Payment: £540 • Paid upon the Freelancer demonstrating development progress against the agreed scope, at the Client's sole discretion • Same conditions as Milestone 1 apply: this payment does not constitute delivery, acceptance, or completion, and does not limit the Client's rights in the event of non-delivery or breach Milestone 3 – Final Payment: £270 • Payable only upon full delivery of all items listed under Deliverables above, functioning as specified, together with transfer of all source code, documentation, and access relevant to the work • Failure to meet these conditions voids entitlement to the Final Payment Money-Back Guarantee & Acceptance Terms: 1. Freelancer's acceptance of these terms. By commencing any work under this project — including, without limitation, accepting the award, confirming a start date, or performing any preparatory or substantive task — the Freelancer is deemed to have read, understood, and irrevocably accepted all terms of this posting in full, including this Money-Back Guarantee & Acceptance Terms clause. Commencement of work by the Freelancer constitutes their binding acceptance of the contract; it is not conditional on any further signature or confirmation. 2. Milestone release ≠ Client's acceptance of the work. Release of any milestone payment by the Client authorises the Freelancer to commence or continue work only. It does not constitute the Client's acceptance of that work or of the final deliverable. The Client's acceptance of the deliverable occurs solely upon the Client's written confirmation that it conforms to the specification set out in this posting. 3. Time is of the essence. The Project Deadline stated above (10 October 2026) is a material term of this engagement. 4. Money-back guarantee. If the completed deliverable(s) are not delivered in full working order by the Project Deadline, and the Client has not granted an express written extension prior to that deadline, this contract shall automatically and immediately terminate (become void) without further notice, and the Freelancer shall refund the Client all sums paid under this contract in full within 5 business days of the deadline lapsing. 5. Extensions. Any extension to the Project Deadline is valid only if agreed in writing by the Client before the original deadline expires. No extension is implied by silence, delay in response, or continued work after the deadline has passed. 6. No waiver. The Client's acceptance of late or partial work, at its sole discretion, does not waive the Client's rights under this clause in respect of any other milestone or deliverable. 7. Survival. This clause survives termination of the contract. 8. Strict no partial acceptance. There is no partial acceptance of work and no payment beyond the Milestones expressly set out above for incomplete or partially functional deliverables. "Substantial completion" or "near completion" does not qualify. Completion of individual components does not entitle the Freelancer to proportional payment. Testing, feedback, or engagement from the Client does not itself constitute acceptance. Acceptance occurs only upon full completion of the Deliverables as set out in this posting. 9. Refund rights (material breach). Failure to deliver a complete, working system as specified in this posting constitutes material breach. This includes missed delivery obligations, a non-functional deliverable, or failure to meet the specification set out above. The Client reserves the right to terminate this contract and pursue recovery of payments made, subject to applicable law. 10. Suspension rights. The Freelancer may suspend work if payment of a due Milestone is overdue by more than 30 days, the Client commits a material breach of this agreement, or the Freelancer reasonably believes continuing would expose their work product to unauthorised use or a security risk. 11. Limitation of liability. Liability under this contract is limited to the total fixed price of £1,350. Nothing in this clause excludes liability for death or personal injury caused by negligence, fraud, or any other liability that cannot lawfully be excluded. 12. Confidentiality. Both parties agree to keep confidential any system architecture, code, credentials, and data shared in connection with this project. This obligation survives termination of the contract. 13. Intellectual property. Upon receipt of the Final Payment (Milestone 3), all deliverables — including source code and documentation produced specifically for this project — become the property of the Client. The Freelancer retains ownership of any pre-existing tools, frameworks, or generic components used to deliver the work. 14. Force majeure. Neither party is liable for delays caused by events beyond their reasonable control, including natural disasters, war, infrastructure failures, or pandemics. 15. Communication requirement. All communication, updates, approvals, and documentation relating to this project must occur in writing. Communication outside of this does not amend this agreement. 16. Governing law. This agreement is governed by the laws of England and Wales, and any disputes fall under the exclusive jurisdiction of the courts of England and Wales.
Project ID: 40704046
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233 freelancers are bidding on average £1,060 GBP for this job

Hello, This is a strong fit for building a dependable AI inference gateway rather than a thin proxy. I can implement the service in Python with FastAPI, exposing clean versioned endpoints that route requests to the appropriate model revision. The architecture will include controlled request queuing and rate limiting for load spikes, configurable response caching where inference results are safely reusable, and consistent error handling for timeouts, unavailable models, malformed inputs, and downstream failures. I’ll keep the gateway modular so additional models and versions can be added without rewriting the service. For reliability, I’ll create focused API Testing coverage across successful inference, validation failures, queue pressure, rate-limit behavior, cache paths, model failures, and edge-case payloads. You’ll receive source code, configuration guidance, API documentation, and a clear testable handoff aligned with the milestones. Which inference backend should the first adapter target—an existing FastAPI service, TorchServe, Triton, or a custom model runner? Which inference backend should the first adapter target, an existing FastAPI service, TorchServe, Triton, or a custom model runner? Regards, Muhammad Awais
£1,500 GBP in 19 days
8.9
8.9

⭐⭐⭐⭐⭐ Build a Reliable AI Model Inference API Gateway ❇️ Hi My Friend, I hope you're doing well. I've reviewed your project requirements and see you're looking for a backend API solution for machine learning models. You don’t need to look any further; Zohaib is here to help you! My team has completed over 50 similar projects in API development. I will create a robust gateway that manages request queuing, model version routing, and error handling efficiently. ➡️ Why Me? I can easily build your AI Model Inference API as I have 5 years of experience in backend development, focusing on Python, Java, and API integration. My expertise includes serving ML models via APIs and ensuring reliable testing for optimal performance. Additionally, I have a strong grip on request handling and error management practices. ➡️ Let's have a quick chat to discuss your project in detail. I would love to show you samples of my previous work. Looking forward to connecting with you! ➡️ Skills & Experience: ✅ Python Development ✅ Java Development ✅ API Design ✅ Request Queuing ✅ Rate Limiting ✅ Error Handling ✅ FastAPI ✅ TorchServe ✅ Testing Discipline ✅ Machine Learning Integration ✅ Version Control ✅ Documentation Waiting for your response! Best Regards, Zohaib
£900 GBP in 2 days
8.0
8.0

Hello, I have experience building backend AI inference platforms and scalable API services using Python, FastAPI, cloud infrastructure, and machine learning deployment frameworks. I can develop a reliable inference gateway that connects ML models with a clean, versioned API layer while maintaining performance, stability, and maintainability. My approach would include designing a FastAPI-based gateway with model version routing, request validation, authentication, rate limiting, and asynchronous request handling. I will implement queue management for high-load scenarios, response caching where suitable, and robust error handling to manage unavailable or failed model responses. For ML serving, I can integrate solutions such as TorchServe, Triton Inference Server, or custom model-serving pipelines depending on your existing models and infrastructure. The system will include automated testing covering normal requests, invalid inputs, high traffic conditions, and failure scenarios. The final delivery will include complete source code, API documentation, deployment instructions, and a test suite demonstrating reliability. I understand the fixed timeline and milestone structure and can provide regular written updates while delivering a production-ready inference API gateway within the required timeframe.
£750 GBP in 1 day
7.1
7.1

Request queuing under load is where an inference gateway usually fails first, so I'd design that part before anything else. I'd build it in Python with FastAPI: a bounded queue per model version and a hard timeout on every model call, so one hung model returns a clean error instead of stalling every other request. Routing goes by explicit version in the path plus a "latest" alias, and the cache key includes the model version, so a new version never serves stale answers. Tests run in pytest against a stub model backend that simulates timeouts, malformed outputs and bursts of concurrent requests. I've built similar multi-model AI services in Python at InsightSpring. Versioned routing with its tests is ready for review by the end of week one, and full delivery lands in the first week of October, ahead of your 10 October deadline. Which framework are the models in today (PyTorch, ONNX, something else), and are they already served or still just checkpoints?
£1,200 GBP in 7 days
6.9
6.9

Hello, I have strong experience with Python, FastAPI, ML inference APIs, model serving, request queuing, rate limiting, caching, and backend testing. I can build a clean versioned inference gateway with model routing, load handling, consistent error management, response caching, and reliable API endpoints. I’ll also provide a solid test suite covering normal, edge-case, and model failure scenarios. I can start immediately and would be happy to discuss the models and deployment environment.
£1,125 GBP in 7 days
6.4
6.4

Hi there, I am Efanntyo, and I'm excited about the opportunity to work on your AI Inference API Gateway project. With extensive experience in backend development and API engineering, I have a strong background in building robust systems using Python and Java. I understand the critical need for efficient request queuing, rate-limiting under load, and seamless error handling in this project. Having previously worked with FastAPI and similar frameworks, I am well-versed in serving machine learning models via API. My approach will focus on developing a scalable, versioned inference API that ensures reliable model version routing and response caching. I will also implement a comprehensive test suite to cover both standard and edge-case scenarios, ensuring the reliability of the API. I am committed to maintaining clear and open communication throughout the project, ensuring alignment with your specifications and expectations. My goal is to deliver a solution that not only meets but exceeds your requirements, providing a dependable backend gateway for your machine learning models. Looking forward to the possibility of collaborating with you on this exciting project. Best Regards,
£1,125 GBP in 14 days
6.7
6.7

Hello!, I am a US-based backend/full stack developer with around 10 years of experience building production APIs, ML inference services, FastAPI backends, queue-based workers, rate limiting, caching, testing, and deployment-ready backend systems. I read your project description carefully and understand this is a pure backend/API build: a clean gateway in front of one or more ML models with versioned routing, request queuing under load, caching where useful, and reliable error handling when a model fails or times out. For this scope, I’d recommend Python + FastAPI, Redis for queue/rate-limit/cache support, Docker, structured API tests, and a simple model-router layer so future models or versions can be added without rewriting the gateway. Relevant work includes: - FastAPI inference gateway for multiple model versions - Queue-backed backend service with retries and timeout handling - API caching/rate-limiting layer for high-volume requests - Automated test suite for edge-case API inputs Could you please clarify the following questions to help me better understand the project? 1. Will the models be called locally, through TorchServe/Triton, or through external endpoints? 2. What request volume or concurrency should the queue/rate limiter be designed for? 3. Should caching be based on exact input matching, user/session rules, or disabled for sensitive requests? Regards, James Zappi
£1,125 GBP in 7 days
6.4
6.4

Hi there, I understand this project requires a production-ready backend inference gateway that exposes versioned ML models through a clean API while reliably handling load, queuing, rate limits, caching, model failures, and edge cases. I’m confident I can build this as a maintainable Python/FastAPI service with clear separation between API, routing, queueing, model execution, and response handling. My approach is to first define the versioned API contract and model registry so requests are routed deterministically to the required model/version without hardcoded logic. Next, I’ll implement asynchronous request queuing, configurable rate limiting, concurrency controls, request validation, timeouts, and structured error responses so model failures or overloaded workers do not destabilise the gateway. Finally, I’ll add controlled response caching where requests are safely cacheable, comprehensive logging, health checks, and automated tests covering normal requests, invalid inputs, queue saturation, rate limits, model timeouts/failures, version routing, and cache behaviour. You’ll receive the working inference API, versioned model routing, queue/rate-limit layer, caching and error handling, test suite, documentation, and complete source code. Which model-serving approach should the gateway support initially: direct Python model workers, TorchServe/Triton, or an existing inference service you already have? I’m ready to start immediately. Warm Regards, Aneesa.
£750 GBP in 2 days
6.4
6.4

As an experienced backend developer with a strong focus on API engineering, I am confident in my abilities to create a robust and efficient AI Inference API Gateway for your project. My expertise lies in Python and Java, both of which are crucial to the task at hand. Having a firm grasp of rate-limiting, request queuing, and consistently handling errors, I promise to deliver an API endpoint that is capable of seamlessly routing through multiple model versions. Furthermore, I've had hands-on experience in serving ML models via APIs using frameworks such as FastAPI, TorchServe, and Triton. I understand the intricate nature of these frameworks and their importance in providing clean and efficient results. With this knowledge, I fully appreciate the significance of building a future-ready backend service that will not only meet but exceed all your project requirements. Web Crest's approach is always tailored to fit the specific needs of clients like yourselves. Our team combines technical expertise with dedicated support to ensure your projects are delivered on time and with maximum functionality. It is with this promise that I interactively manage each project using Agile methodology, ensuring transparency through open lines of communication and quick response times. Together, let's build an exceptional AI Inference API Gateway for your business!
£1,200 GBP in 7 days
6.5
6.5

Hi, I'm Denis, a full-stack developer with solid experience building backend systems that serve ML models at scale. I've worked on similar inference gateways where the core challenge was handling variable load while keeping response times predictable. I understand what you're building: a reliable API layer between clients and ML models that handles routing requests to the right model version, queuing during peak load, caching responses, and failing gracefully. This is straightforward backend work, but it needs to be solid because it's the critical path between users and models. I've built systems like this using Python and FastAPI. Versioning and routing logic require clear thinking around state management and error handling. Request queuing and rate limiting are well-understood problems, but comprehensive testing is crucial since edge cases in ML pipelines can be subtle. My approach: start with a requirements review to nail down model interfaces and load patterns. Then build the core API with versioned routing, add queuing and rate-limiting, implement response caching with sensible TTL logic, and create a comprehensive test suite covering happy paths and failure modes. I'd deploy incrementally to validate each piece. The key is understanding how your models fail and acceptable fallback behavior—that shapes error handling and retry logic. I'd want clarity on that early. I can start right away. Let's discuss the details. Thanks, Denis.
£750 GBP in 8 days
6.2
6.2

Hi, I reviewed the project and understand the main requirement: a reliable, versioned AI inference API gateway that exposes machine-learning models without UI work. I can build the Backend Development service in Java, implementing versioned model routing, request queuing, rate-limiting, response caching, and consistent error handling. The design will support Cloud Computing deployment and AI (Artificial Intelligence) HW/SW integration, with clean inference endpoints and API tests covering standard and edge-case inputs. I’ll keep the implementation secure, maintainable, well documented, and responsive throughout the three milestones, with clean source code and reliable pipeline testing for production readiness. Let’s discuss here now.
£750 GBP in 30 days
5.9
5.9

Hi, We've built AI services in Python with Flask sitting in front of OpenAI and Gemini, handling queuing, caching in Redis, and consistent error handling when a model call fails. For one AI SaaS we ran model inference through a Flask backend with AWS deployment and version control on the pipeline, plus a test suite covering edge-case inputs. One thing worth deciding early: your version routing. Do you want routing by request header, by URL path like /v2/, or a per-model config the gateway reads at startup? That choice shapes the caching key strategy and how graceful the failover is when one model version is down. On the milestones, since we hold source and access, we can scope Milestone 1 as the endpoint plus routing skeleton with tests so you see running work first. Which model server are you leaning toward, Triton or TorchServe? Adil
£1,237.50 GBP in 21 days
6.0
6.0

How are you planning to handle a model that's mid-inference when a newer version needs to take over its traffic, drain the in-flight queue first or cut over immediately and let the client retry? That decision shapes half the gateway, and it's usually skipped until the first deploy goes wrong. I'd build the queue as a bounded async worker pool per model version, with backpressure returning 429 once the pool's saturated rather than piling requests into memory until the process falls over. Version routing reads a header or falls back to a default pinned version from config, so a client can stay on a known-good model while a new one warms up behind it. Caching sits in front of the queue as cache-aside keyed on input hash plus model version, since the same input can validly return different results across versions and a version-blind cache would serve stale answers silently. Failure handling is a circuit breaker per model, tripping after a run of consecutive failures or timeouts so a broken model gets short-circuited to a clean error instead of backing up the whole gateway, with a half-open probe to bring it back automatically once it recovers. M1: queue with backpressure + version routing skeleton, £340, 4 days. M2: cache-aside layer keyed on input hash and model version, £350, 4 days. M3: circuit breaker and consistent error responses on failure, £350, 3 days. M4: test suite, load test, docs, £310, 3 days. Fits inside the 14 days with room to spare. Is the queue meant to be strictly FIFO per model, or does it need to prioritize by client tier? And should the cache persist across restarts, or is in-memory fine for a first pass?
£1,350 GBP in 14 days
6.0
6.0

With hands-on experience in backend/API development using Python and serving ML models via FastAPI, I am well-equipped to build your AI Model Inference API Gateway. Could you provide insights into your preferred error-handling approach for failed model responses? Regards, Yogesh Kumar
£870 GBP in 6 days
5.6
5.6

I would build this as a thin, model-agnostic inference gateway rather than coupling the API directly to one ML runtime. FastAPI would expose versioned endpoints, with a model-adapter layer handling routing to the requested model/version. Redis can provide bounded request queuing, rate limiting and version-aware response caching. I’d also implement per-model timeouts, normalized error responses, request IDs and circuit-breaker behaviour so an unhealthy model does not cascade failures through the API. The test suite would cover valid/invalid input, version routing, queue saturation, rate limits, cache behaviour, model timeout/failure and recovery. My background includes FastAPI, AI/ML integrations, backend APIs and production SaaS systems. I can start immediately once milestone acceptance and refund terms are tied to objective test criteria.
£1,350 GBP in 14 days
5.7
5.7

Hello, I can see the real challenge here isn’t just exposing a model, it’s keeping inference predictable when load spikes, versions change, or a model fails mid-request. That’s exactly the kind of backend problem I solve with Python, FastAPI, queueing/rate-limiting, and solid API testing. I’ve built backend services with clean versioned routing, resilient error handling, and integration layers that stay stable under pressure. For this gateway, I’d structure the service so each model version is routed intentionally, cached responses are used only where safe, and failures return consistent, client-friendly results. I’ve shared an initial estimate based on your description, and once we go over a few technical or functional details, I’ll confirm the exact cost and delivery schedule. Looking forward to aligning on the API flow, queue behavior, and test coverage so we can finalize the exact plan. How are you expecting model versions to be selected—by request header, endpoint path, or a registry-based routing rule? Thanks, Asad
£750 GBP in 20 days
5.6
5.6

⭐⭐⭐⭐⭐ Built high‑load AI inference gateways with versioned model routing, queuing, caching and rock‑solid API reliability
£1,234 GBP in 7 days
5.3
5.3

Nice to meet you , It is a pleasure to communicate with you. My name is Anthony Muñoz, I am the lead engineer for DSPro IT agency and I would like to offer you my professional services. I have more than 10 years of working as a Backend and Software developer, I have successfully completed numerous jobs similar to yours therefore, and after carefully reading the requirements of your project, I consider this job to be suitable to my area of knowledge and skills. I would love to work together to make this project a reality. I greatly appreciate the time provided and I remain pending for any questions or comments. Feel free to contact me. Greetings
£1,047 GBP in 7 days
5.7
5.7

I’d begin by defining versioned routes such as /v1/infer and /v2/infer, with a routing layer that can select the required model version without exposing serving details to API consumers. Within 4 days, you will receive a containerised FastAPI inference gateway with model-version routing, bounded request queuing/rate limits, selective response caching, consistent failure responses, and automated API tests for normal, invalid, overloaded, and model-timeout cases. I’ll use async request handling with explicit queue limits and timeouts so load sheds predictably rather than exhausting workers; cache keys will include model version and only apply to safe, deterministic requests. I previously fixed frozen charts in a live trading platform by adding caching, request-credit budgets, and a last-good-value fallback around an unthrottled data API. Will the gateway initially route to one model-serving backend, or should it support multiple providers from the first release? Muhammad Saad
£1,050 GBP in 4 days
5.0
5.0

I can build the backend AI inference API gateway you described: a clean, versioned, production-ready service that routes requests to the correct model version, enforces rate limiting, and queues requests safely under load. The gateway will include robust, consistent error handling so failures from downstream models return predictable responses. Implementation will focus on: - Versioned inference endpoints and model routing - Request queuing + rate limiting for stability during bursts - Response caching where appropriate to reduce latency - Strong test coverage (standard + edge cases) for API reliability You’ll receive working endpoints plus the full source code, documentation, and access needed to run and maintain the gateway, aligned to the fixed £1,350 GBP / 3 milestone structure and the 10 October 2026 deadline.
£750 GBP in 4 days
5.2
5.2

Fulham, United Kingdom
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Member since Sep 10, 2026
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