Backend Event Streaming Service Development

1. Real-Time Event Streaming & Message Queue Service

Category: Backend Development / Distributed Systems
Budget: £1,350 GBP — Fixed Price, 3 Milestones
Project deadline: Tuesday, 6 October 2026

Description:
We need a backend engineer to build a real-time event streaming service that ingests high-volume events from multiple producers, queues them reliably, and routes them to downstream consumers with guaranteed delivery ordering. The service needs to handle backpressure gracefully, support consumer groups, and expose a clean internal API for publishing and subscribing to topics. This is purely a backend/messaging-infrastructure build — no UI involved.

Key requirements:
• Strong experience with Kafka, RabbitMQ, or a comparable message broker
• Solid understanding of event-driven architecture and idempotent consumers
• Experience designing internal pub/sub or queueing APIs
• Comfortable working against a fixed one-week delivery window

Deliverables:
• Working event streaming/queueing service with producer and consumer interfaces
• Documented topic/queue structure and delivery-guarantee design
• Basic monitoring hooks for queue depth and consumer lag

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 (6 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.