Team Required — SQL Backend, Payments and Real-Time Sessions — Fixed Price in CAD

@Microlent

Hello, I am Dr. Rajesh Rolen, PhD in Computer Science & Engineering, with experience of over 20+ years in API Development, Backend Development, SQL As a preferred freelancer in the top 1%, I have done 400+ projects here on freelancer.com, I have 4.9 ratings out of 5 on average, which showcases my quality of work and timely delivery. Key Highlights: - Free Hosting Support on the Cloud or any desired platform. - Free 3 months of post-delivery support to ensure that our client doesn’t face any challenges after the launch of the project. - Free Dedicated tester on projects to ensure quality delivery, so clients don’t need to act as a tester. - 10+ Years experience UI/UX team to ensure intuitive UI. Portfolio: https://www.freelancer.com/u/Microlent Please open the chat and send me a message, so we can have a more detailed discussion about the project to give you the project timeline and cost. Thank you for considering my services. I look forward to engaging in a productive conversation and understanding how I can be of assistance in bringing your project to life. Regards Rajesh Rolen

@diektech

Hi — Elias here from Miami. I see you’re looking to build a SQL backend with payment processing and real-time sessions. A seamless user experience and reliability are critical for your project. The real technical challenge often lies in ensuring the system can handle real-time data while managing payments securely. What usually matters most here is how we design the architecture to prevent bottlenecks, especially under heavy load. A common issue in systems like this is maintaining data integrity during peak times, which requires careful planning of database and API interactions. My approach would focus on structuring the backend for scalability and maintainability. I prioritize building a solid foundation that supports growth and integrates smoothly with payment gateways and session management. This way, we can adapt to changing requirements without extensive refactoring. I’ve worked on similar projects involving complex backend systems and payment integrations, allowing me to anticipate potential pitfalls. A few questions to better understand the scope: Q1 – What specific payment gateways are you considering? Q2 – How do you envision user roles and permissions being managed? Q3 – What are your expectations for data load and user traffic in real-time sessions? Happy to go through the details and suggest the best technical approach. Looking forward to hearing from you.

@corpmember29

Hello, SQL BACKEND + PAYMENTS + REAL-TIME SESSION SYSTEM {{{ I HAVE CREATED SIMILAR BEFORE AND I CAN SHOW YOU }}} I understand you need the existing SQL schema, backend integrations, payment processing, access entitlements, and real-time session flow completed, integrated, and fully tested with strong protection against duplicate transactions, concurrent redemption, interrupted payments, and reconnection issues. I can finalize the SQL schema, migrations, constraints, transactions, retries and rollback, secure complimentary-code generation/redemption, account and entitlement recovery, hosted payment checkout, signed payment webhooks, reconciliation and background processing. I can also connect entitlements to the existing real-time sessions with fair waiting/queue handling, duplicate-reservation prevention, session consumption only after activation, reconnection recovery, and resource cleanup. I will cover production security, rate limiting, TLS, monitoring, deployment, backups/restoration, documentation, and comprehensive failure/concurrency testing while ensuring conversation content is not stored in SQL, logs, or backups. I have 11+ years of experience in SQL, backend development, payment integrations, real-time systems, authentication, transactions, webhooks, recovery workflows, and production deployments. I CONFIRM DELIVERY BEFORE 7:00 P.M. QUEBEC TIME ON SEPTEMBER 23, 2026. I WILL PROVIDE 2 YEAR FREE ONGOING SUPPORT AND COMPLETE SOURCE CODE. Thanks, Christina

@Hubready

Hello!, This is James from Hollywood... I read your post as a need for more than “just backend help” - you need a team that can keep SQL data clean, make payments reliable, and handle real-time sessions without lag or broken state. That’s exactly the kind of build I like. My approach: 1. Review the current database, payment flow, and session logic 2. Identify edge cases, bottlenecks, and failure points 3. Build in phases: SQL structure, API layer, payment processing, then real-time session handling 4. Test thoroughly for race conditions, retries, security, and data consistency I care about the small things here, because projects like this usually fail on details like duplicate charges, session desync, poor query design, or weak state handling. I’ll make sure the foundation is solid, not just “working for now.” Relevant work: - SaaS billing backend with subscription + invoice handling - Real-time booking system with live session updates - SQL-driven operations dashboard for a service company - Payments and user session flow for a marketplace app A few quick questions: 1. Do you already have the SQL schema and payment provider chosen? 2. Is the real-time session part chat, booking, live tracking, or something else? 3. Do you want a full backend build, or a focused fix/rebuild of specific modules? If you want someone who will think through the risky parts and deliver this properly, I’m ready to chat.

@gotucat

Hi, I reviewed the request for an end-to-end SQL backend that handles payment processing, complimentary codes, entitlement issuance, and real-time session access management with recovery and concurrency safety. I’ll finalize the prepared schema and migrations, implement transactional data access and constraints so entitlements are never double-consumed, and wire the backend to the existing real-time session flow for confirmed-active consumption, reconnection rules, and fair waiting/queue allocation. I’ll also integrate the payment provider with server-side confirmation, signed notification verification, duplicate/out-of-order handling, and background reconciliation so every confirmed payment results in exactly one entitlement. I deliver clean, testable code with careful rollback/restore support and monitoring readiness. I confirm delivery before 7:00 p.m., Quebec time, Wednesday, September 23, 2026. Let’s discuss here now.

@sufyanasmat38

I have experience building SQL-backed real-time platforms with secure payment integrations, entitlement systems, webhooks, background jobs, retries, reconciliation, authentication, and concurrency-safe workflows. I can complete the database, backend integrations, complimentary codes, payment confirmation, entitlement recovery, session allocation, queueing, and production security while preserving your existing real-time architecture. I’ll ensure duplicate payments, webhook retries, concurrent redemptions, reconnections, and interrupted sessions cannot double-issue or consume entitlements. I can also handle failure/recovery testing, deployment, rollback, monitoring, and documentation. I can start immediately and explicitly confirm delivery of the complete agreed scope before 7:00 p.m. Quebec time on September 23, 2026. I’d be happy to share relevant SQL, payment, real-time, and recovery projects along with recent project references.

@devendrathakur12

Hi, I’m a Senior Backend Engineer with 20+ years in SQL and payment integrations. I have gone through your specific requirement for entitlement and payment backend. I built something like this for business clients, with 20+ years across backend work, including Linfohub. I would use PostgreSQL transactions rather than application-only locking because duplicate redemption and payment callbacks need atomic state changes. I will build the backend services around entitlement issuance and session consumption. Node.js will handle payment callbacks and PostgreSQL transactions, while a background worker retries failed reconciliation jobs. And I’ll connect the existing real-time state to entitlement checks so reconnects cannot consume twice, at least that is where I would start. Relevant SQL, payment and backend samples I can send. Which payment provider and real-time session code are already in place? How is session capacity currently tracked and queued? Can you share the July or August 2026 project references required for verification? I confirm delivery before 7:00 p.m. Quebec time on September 23, 2026. Free for a quick call this week? Or answer those three and I’ll map out the first pass tonight. Dev Singh

@rizwange4

Hi, We can complete the SQL backend, payment integration, entitlement management, and real-time session flow with a strong focus on reliability, security, and recovery. We’ll handle database setup/migrations, complimentary codes, authentication, hosted payments, signed webhooks, duplicate-payment protection, entitlement recovery, waiting/queue management, session consumption, reconnection handling, retries, monitoring, and production security. We’ll also thoroughly test concurrent requests, failures, rollbacks, duplicate notifications, and recovery scenarios. We can provide relevant examples of SQL, payment, and real-time system integrations and discuss milestone-based delivery after reviewing the technical documentation and existing code. Best regards, Muhammad Rizwan LA

@denisSolution

Hi, I'm Denis, a backend and real-time systems developer who has built SQL-backed systems with payment flows, access control, and concurrency handling. This project needs a reliable backend that coordinates session entitlements, payments, and real-time state without ever double-consuming credits. I’ll extend the provided schema with strict transaction control, idempotent payment handling, and background reconciliation for out-of-order or lost notifications. The existing real-time relay will be connected to the new backend using signed session tokens so reconnection never wastes a session. Complimentary code generation will include rate-limited batch export with cryptographic validation and immediate deactivation after redemption. I’ve recently worked on a similar system where payment confirmations, queue management, and recovery logic had to remain consistent under load. The deliverables will be the completed schema, migrations, and integration code, plus documentation and one-click deployment scripts. The main risks are unclear third-party rate limits and edge cases in background job retries; these will be handled with idempotency keys and manual override hooks. All testing will cover duplicates, network failures, and recovery. I can start working right away. Let's connect and discuss the details. Thanks, Denis.

@ukroficer

✅ Hello, You need the SQL backend, payment processing, entitlement recovery, and real-time session access completed around an existing flow, schema, and tests, with strict idempotency for duplicate notifications, concurrent redemption, and reconnection. We would first review the current codebase, SQL scripts, state handling, and payment touchpoints, then lock the final integration path to meet delivery before 7:00 p.m. Quebec time on Wednesday, September 23, 2026. - Proposed stack: Laravel 11 + PostgreSQL, if your current codebase does not require another fit. - Design REST APIs, auth, entitlement ledger, idempotency keys, and signed webhook handling. - Integrate hosted checkout, recovery flow, queueing, background jobs, retries, and reconciliation. - Add concurrency tests, failure recovery tests, monitoring, deploy scripts, backup and rollback. We are Webcapitan, a Ukraine-based studio with 8+ years, Preferred Freelancer status, and 5★ across 580+ reviews. Is this an existing PHP codebase, and if so which framework/version is already in place? Is the designated payment provider already chosen, and is any DB schema or webhook contract final? Please let me know your thoughts. Looking forward, Roman

@sagarwal3005

Completing the SQL database and backend integration for your interactive avatar service requires a detailed approach to ensure secure payment processing and effective session management. I will finalize the existing SQL schema, implement robust transactions, and enable secure batch generation for complimentary codes while ensuring that concurrent access does not lead to entitlement conflicts. My skills in Node.js, Express, and SQL databases position me well to manage these backend tasks effectively. I maintain a 4.9-star rating across 200 client reviews, having completed 220 projects with a 97% project-completion rate. Can you confirm the specific requirements for session management and the existing components you would like to reuse?

@mahads31

As a seasoned tech partner, specializing in web, mobile, and SaaS development, I bring to the table a well-rounded set of skills that aligns perfectly with your project requirements. With expertise in API development, backend development, and database management among others, your project's core needs are addressed skillfully. My proven track record in turning complex requirements into scalable systems ensures the delivery of an efficient product designed for lasting success.

@installerpoint

Hello, I can take ownership of the SQL/backend, payment, entitlement and real-time session integration and complete the work without unnecessarily rebuilding the components that already exist. I understand this is a production-oriented integration project where correctness under concurrency and failure conditions is critical, not simply a CRUD/API implementation. Technical approach I’ll review the existing code, SQL schema, session state management and automated tests first, then extend the current architecture. Key areas I’ll implement and validate: SQL schema, migrations, constraints and secure data access Transaction-safe entitlement creation and consumption Atomic single-use complimentary-code redemption I’ll work exclusively against the agreed scope and will not introduce additional paid dependencies without approval. AI-assisted development tools such as Codex or Claude can be used where they improve development speed, but all generated code will be reviewed, tested and validated before delivery. Responsibility for the final implementation remains with me/the development team. I can provide verifiable examples and references for relevant SQL/backend, payment, recovery and real-time integration work during the selection process. I’m ready to review the existing codebase and technical specification with you and begin implementation immediately after scope confirmation. Best regards ADEEL

@tyronet2

You need a senior-level training program that moves beyond syntax and teaches experienced engineers how to make better architectural, operational, and delivery decisions. I bring 9+ years of production software experience across distributed systems, cloud infrastructure, full-stack platforms, and AI-assisted development. At Marin Software, I worked with Python, AWS, real-time pipelines, and LangChain agents, giving me practical material for architecture and troubleshooting exercises. I’ll structure the program around system design, scalability, API and data architecture, testing strategy, security, observability, CI/CD, cloud-native delivery, performance, and responsible AI engineering. Each module will include learning objectives, concise theory, production-style case studies, hands-on labs, code reviews, failure scenarios, assessments, and instructor notes. I can provide a sample module outline first, then deliver the complete curriculum and reusable training assets. What course duration, delivery format, primary tech stack, and seniority level should the program target?

@CorporateRD

Hi there, I understand that you want are looking for complete the backend, SQL database, payment, entitlement, and real-time session system for an interactive avatar service. The system will support free access codes and paid time-based sessions with secure payments, queuing, recovery, reconnection, and strong data protection. Right? 1. Can you share the existing technical documentation and current code structure with us so we can understand the SQL schema, backend, real-time session system, and unfinished components? 2. Which payment provider will be used for the CAD $0.99 sessions, and is the production merchant account already ready? Also, do you already have the required webhook and hosted-checkout credentials available for testing? 3. For the real-time sessions, what is the current allocation logic when all available sessions are occupied? Do you already have a queue mechanism that we should extend, or should we complete the waiting and allocation logic from the existing implementation? I start by reviewing the existing code, SQL schema, real-time session flow, payment requirements, and tests to identify what can be reused. Then I complete the backend in controlled stages, focusing on secure entitlements, payment confirmation, queue/session management, recovery, concurrency, and automated testing before final deployment and handover. Budget and Duration are placeholders. Regards, Royal Design :)

@Tanmoy236

Hi There! I specialize in backend, SQL, payment and real-time systems with 9+ years of experience. Our team can complete the existing backend integration with strong focus on transaction safety, duplicate prevention, entitlement recovery and reliable session consumption. We’ll finalize the SQL/migrations, payment webhooks, complimentary codes, authentication, queues, retries, reconciliation, real-time session integration and production security, then test failure/concurrency scenarios end-to-end. We explicitly confirm delivery by 7:00 p.m. Quebec time on September 23, 2026. Can you share the existing code and technical documentation for review?

@Eliteinno

Hello, Is your current SQL schema compatible with the existing real-time state management? Do you have a preferred payment provider already selected? Excited about your avatar service! I'll ensure seamless integration and focus on robust entitlement management to prevent duplicate session issues. Let's discuss the timeline and costs in more detail after reviewing your full requirements together. Looking forward to a chat to explore further steps. Feel free to message me anytime!

@emilesd617

Hi, I am a backend developer with 8 years of rich experience in software development, with a strong background in SQL systems, payment integrations, and real-time applications. I am familiar with SQL, PostgreSQL, Node.js, Python, REST APIs, WebSockets, database transactions, concurrency control, payment webhooks, background jobs, authentication, Docker, Linux, TLS, and automated testing. I can confirm delivery before 7:00 p.m. Quebec time on September 23, 2026. My proposed fixed price is CAD $1,560,with milestones tied to database/entitlements, payments/recovery, real-time session integration, and final production testing and documentation. I'm an individual freelancer, but I can coordinate with the existing development team and work on any time zone you want. Please contact me with the best time for you to have a quick chat and review the existing architecture and detailed scope. Looking forward to discussing more details. Thanks. Emile.

@longngoc2307

Hello, Truong here. "SECURE SQL + PAYMENT BACKEND" — you need reliable entitlement handling across payments, complimentary codes, real-time sessions, retries, and recovery. I’d use PostgreSQL with transactional, idempotent backend operations so duplicate payments or concurrent redemptions can never create two entitlements. I’d also connect the existing session state to a durable queue/worker for retries, reconciliation, recovery, and safe consumption. I confirm delivery before 7:00 p.m. Quebec time on September 23, 2026. Can you share the existing SQL schema, backend code, and real-time session implementation for review? Looking forward to work with you