FinTech Dev Needed for Real-Time Payments App

@shivmirthyusl

Hi, With almost two decades in the industry and over 483 successful projects, we are the go-to experts for delivering reliable, scalable, and business-focused technology solutions – just like your project demands. When it comes to digital finance, we have a rich history of crafting powerful tools that prioritize speed and security. In fact, our teams are versed in integrating diverse financial APIs and handling transactional challenges with utmost precision – a skillset that will prove invaluable when dealing with real-time payments as crucial as those on Australia's NPP and PayTo platforms. With solid experience in backend development using Node.js (one of the preferred languages on these platforms) and proven expertise in deploying cutting-edge encryption like AES-256 and OAuth 2.0, we ensure data security while facilitating swift transactions. Additionally, our familiarity with Go and Python ensures we're able to adapt to various scenarios seamlessly. Lastly, we understand that time is of the essence in fintech development, which is why our agile milestone-based approach fits perfectly into your specified timeframe of 2-3 months. Thanks, SBM

@ixorawebmob

Hello, I’ve gone through your project details and this is something I can definitely help you with. I have 10+ years of experience in mobile and web app development, working with Flutter, Android, iOS, React, Node.js, and APIs. I focus on clean architecture, scalable code, and clear communication to ensure the project runs smoothly from start to finish. I will first review your requirements, suggest the best technical approach, and then proceed with development while keeping you updated at every stage. Here is my portfolio: https://www.freelancer.in/u/ixorawebmob I’m interested in your project and would love to understand more details to ensure the best approach. Could you clarify: 1. Do you need this for mobile, web, or both? 2. Do you already have UI/UX designs or should we create them? 3. Will there be any third-party API or payment gateway integration? 4. What is your expected timeline for completion? 5. Are there any reference apps or websites you like? Can you specify the required security protocols for API integration in your payment app? Let’s discuss over chat! Regards, Arpit Jaiswal

@mubeenm5026

As a FinTech specialist with an impressive track record, I believe my skills and experience at Web Crest perfectly position me to help bring your vision to life for your real-time payments app. My experience includes integrating API functions, specifically in the realm of finance, and I'm well versed in handling webhook failures or transaction drop-offs. I have a deep understanding of the importance of detail-oriented security practices, such as deploying secure encryption, OAuth 2.0, and device biometric token validation - all key components specified in your project's requirements. At Web Crest we don't simply focus on building applications; we strive to deliver scalable, maintainable solutions through our agile project management approach. This aligns with your project's scope - a backend MVP that demonstrates smooth integration of critical processes. Additionally, we understand the gravity of financial security which makes us an ideal fit given the high level of encryption you require in this payments system. I’ve worked on numerous projects involving payments similar to what you need. The backend languages we're proficient in - Node.js, Go and Python - combined with robust databases (PostgreSQL/MySQL) proficiency and strong financial data security understanding assure effective implementation of Reliable yet efficient APIs for third-party banking services via Monoova or Zepto.

@kamrankhan089

Hi, I have read the job description. I have have worked on fintech app with fidar company. The company is is india base. I am senior devloper. I am ready for live interview which will best for both of us. Thanks

@mahig47

HELLO, Your real-time payments MVP needs a secure backend capable of connecting Australian banking rails, merchant QR payments and transaction workflows reliably. I’ve already developed fintech/payment platforms involving digital wallets, payment gateways, transaction ledgers, third-party banking APIs, webhooks and secure payment processing, so I’m familiar with the requirements of this type of product. I can build the backend using Node.js, Go or Python with PostgreSQL and Redis, integrating BaaS APIs such as Monoova/Zepto and implementing the required NPP, PayTo and PayID flows. Dynamic merchant QR codes can be generated around the required ISO 20022 payment structure, with secure API communication, webhook handling, transaction state management and sandbox testing. Security will be built into the architecture with OAuth 2.0, AES-256 encryption, secure token handling and device/biometric validation. I’ll also structure the ledger and payment workflows for accurate reconciliation, retries and auditability, with clean APIs and documentation for future expansion. If you share the BaaS provider you’ve selected and the intended merchant payment flow, I can map the MVP architecture and end-to-end transaction lifecycle. Regards, Nikita Gupta

@pinkeegupta

Hi I previously integrated a payment/financial transaction API into a web and mobile application, handling payment initiation, transaction status, callbacks, and reconciliation. For webhook failures, i implemented secure webhook validation, idempotent transaction handling, logging, retry mechanisms, and scheduled status verification through the API. I am having expertise in Native on Android Java, kotlin and IOS Swift, and For Hybrid Cross platform on Flutter Dart & React- Native and for web and backend on react js and node js, Python Django. Please consider me and initiate a chat for further detailed discussion. Regards, Anju

@softwarelinkerrs

Having extensive experience in building secure and scalable digital systems, I'm confident that my team at SoftwareLinkers can deliver on your FinTech project. We have proven expertise in API development and integration with mobile and web platforms and have successfully integrated financial transaction APIs in the past while addressing any glitches that arose. Our PHP & MySQL backend development skills align directly with your project's needs. We are familiar with PostgreSQL/MySQL databases and Redis caching and have a strong understanding of financial data security standards crucial to your application's success. Additionally, we offer optional AI-powered features which can enhance your app's functionality. What sets us apart is our focus on long-term partnerships rather than just delivering code. We invest time to deeply understand your business goals and design efficient, reliable systems tailored to those goals. Furthermore, we offer comprehensive maintenance and support services well beyond the project completion to ensure your app runs smoothly even after deployment. Choose us for a professional team that delivers results, on-time, and with clear communication. Let's discuss how we can turn your vision into reality!

@Hrolgar

First off, get a signed idempotency key or nonce into the BaaS webhook headers before anything else touches the transaction state machine, since Monoova and Zepto will both retry a callback on timeout and a payment marked settled twice on a QR merchant terminal is the failure mode that actually loses money here. That state machine is the piece I'd build first: pending, authorised, settled, failed, reversed, with the webhook handler doing signature verification against the provider's public key before it's allowed to touch state, and a retry queue with exponential backoff sitting behind it for the drop-off cases NPP webhooks are known for. PayID and PayTo add a second wrinkle since they're two different consent and mandate models even inside one BaaS provider, so the ISO 20022 payload generation needs to branch there rather than assume one shape covers both. I'd wire OAuth2 client credentials for the BaaS side and a separate token flow for the biometric validation path on the app side, since conflating them is where a lot of these integrations get tangled. AES-256 at rest for anything touching PayID aliases and mandate references, TLS for transport, nothing exotic needed beyond doing it correctly and testing it against real sandbox drop scenarios, not just the happy path. Sandbox end to end: QR generation, PayID resolution, PayTo mandate creation, NPP settlement webhook, ISO 20022 message on both legs, reconciliation against provider ledger. That's the MVP. M1: Core auth, OAuth2 setup, BaaS sandbox account wiring, project scaffolding. $36000 INR, 8 days. M2: Transaction state machine, webhook receiver with signature verification and retry/backoff. $43200 INR, 14 days. M3: QR merchant payment flow, PayID resolution, ISO 20022 payload generation. $39600 INR, 14 days. M4: PayTo mandate creation and lifecycle, biometric token validation backend. $32400 INR, 12 days. M5: End-to-end sandbox simulation, reconciliation, hardening, handover docs. $28800 INR, 12 days. The number above is built off the brief as posted, not a locked quote. Whether it moves depends mostly on which BaaS provider you've actually got sandbox access to right now and how far along their PayTo mandate API is, since that's the part of the two providers that varies most in maturity. Send me the repo and I'll have a tighter number tomorrow.

@kishanbwts

I recently helped a startup build a real-time payment gateway that integrated multiple banking APIs similar to Monoova and PayTo. For webhooks, I set up automatic retries with exponential backoff and implemented a dead-letter queue to capture and manually review failed transactions. This ensured no payment drop-offs and reliable synchronization with the core ledger. For your backend, I suggest using Node.js with AES-256 encryption for data security, combined with OAuth 2.0 and biometric token support to meet your device validation needs. I can also develop dynamic merchant QR codes formatted to ISO 20022 standards, tested thoroughly within the NPP sandbox for smooth end-to-end payment flows. Two quick questions: Are you planning to support multi-merchant accounts or just single-merchant QR transactions initially? Also, do you already have access to any sandbox environments for your chosen BaaS providers? I’m ready to get started on your MVP and deliver your core payment backend on a milestone basis, ensuring secure, real-time transaction processing from day one.

@jayantkumar314

Hi, I can build the secure backend MVP around the BaaS APIs, payment webhooks, QR payment flow, PostgreSQL/Redis and OAuth-based authentication. For transaction webhooks, I use idempotent processing, persisted transaction states, retry handling and reconciliation so duplicate or missed callbacks do not corrupt payment status. I’d first validate the selected NPP/PayTo provider’s sandbox APIs and ISO 20022 requirements before locking the payment architecture and milestone

@abhishek060

The critical part of this MVP is not just integrating a BaaS API—it is ensuring the payment state remains correct when webhooks are delayed, duplicated, or never received. I would approach the backend around an explicit transaction state machine, with idempotency keys, signed webhook validation, retry handling, and reconciliation for unresolved payments. Also, keep the Monoova/Zepto integration behind a provider layer so the core payment and ledger logic is not tightly coupled to one BaaS provider. I can work with Node.js/Python backends, PostgreSQL, Redis, secure API integrations, authentication, and transaction-based application flows. For this project, I would focus first on the end-to-end sandbox payment lifecycle before expanding the MVP. After the NDA, I can review the technical brief and map the MVP into clear integration and delivery milestones.

@sanjana22kr

hello there , I can help build your Australian real-time payments MVP with a secure, scalable backend and reliable payment processing architecture. I can cover: NPP / PayTo / PayID and Australian BaaS REST API integrations ISO 20022-compliant payment payloads and dynamic merchant QR generation Node.js/Go/Python backend with PostgreSQL/MySQL + Redis OAuth 2.0, AES-256 encryption and secure device/token validation Webhooks, transaction states, reconciliation and idempotency End-to-end testing in the NPP/SWIFT sandbox Production-ready architecture, logging, monitoring and documentation Screening Question: I have integrated financial transaction/payment APIs where reliability was critical. I handled webhook failures using idempotent transaction IDs, persistent transaction states, retries with backoff, webhook validation and reconciliation jobs. If a payment dropped or a webhook was missed, the system could safely re-query the provider and recover the transaction without creating duplicate charges or ledger entries. I’m comfortable signing an NDA before reviewing the full technical specification and working milestone-by-milestone across the proposed 2–3 month MVP. looking forward to work with you thanks

@ranjika08

The hard part in this MVP is not just connecting to a BaaS API, it’s making sure every QR-triggered payment can survive webhook misses, duplicate notifications, and sandbox edge cases without corrupting transaction state. I’d approach it with a clean payments core, provider abstraction, strict idempotency, encrypted sensitive fields, and recovery jobs from day one so the backend stays stable as you move from MVP to production readiness. My relevant work has included secure API-led flows for payments and financial data, where transaction lifecycle control mattered more than UI. In a previous transaction integration, we handled drop-offs by logging each state transition, verifying webhook signatures, retrying failed consumers through queues, and running scheduled reconciliation against the payment provider so orphaned or pending records were automatically reviewed and corrected. A couple of points will help size this properly: - Will the QR payload only initiate PayTo/NPP requests, or also encode merchant/session metadata for downstream reconciliation? - Do you need PCI-style design precautions only at application level, or are there extra compliance expectations already defined by your advisors? - Should the MVP be delivered as documented APIs plus deployment in sandbox, or do you also need production-ready DevOps setup?

@ammarahmed20

With over 40 successful projects, I'm Ammar Ahmed, a freelance developer who's more than just about building websites. My expertise includes API Development, Mobile App Development, Node.js, Payment Gateway Integration and Python. I bring not just technical skills but also industry-specific knowledge to the table. For instance, my experience in integrating financial transaction APIs gives me comfort with your specific project needs. It emphasizes more on SWIFT/NPP, ISO 20022-compliant payload generation along with secure QR code integrations and exceptional backend development skills. My valuable experiences with payment gateways comprise the usage of Stripe for escrow and handling over $100K monthly, making me well-acquainted with banking-as-a-service (BaaS) APIs like Monoova and Zepto mentioned in your project description. I always strive for production-first mentality developing clean code within specified timelines aiding your budget. Moreover, I understand the importance of data protection in a project of this nature. Hence I specialize in using AES-256 encryption, OAuth 2.0 and device biometric token validation for secure transactions as well as robust databases like PostgreSQL/MySQL and Redis for efficient storage and caching.

@gagansahay695

Hi, I'd be glad to help build your real-time payments app MVP using Australia's New Payments Platform (NPP), PayTo, and PayID infrastructure. I will design a secure backend using Python, integrating third-party Australian Banking-as-a-Service (BaaS) REST APIs and webhooks, and implement an ISO 20022-compliant payload to generate secure, dynamic merchant QR codes. My approach will include deploying and debugging end-to-end payment simulations inside the SWIFT/NPP developer sandbox, ensuring AES-256 encryption, OAuth 2.0, and device biometric token validation. I will also handle webhook failures or transaction drop-offs using retry mechanisms and transaction logging. I can cover: • Secure backend design and implementation using Python • Integration of third-party BaaS REST APIs and webhooks • Implementation of ISO 20022-compliant payload for merchant QR codes • Deployment and debugging of payment simulations in the SWIFT/NPP sandbox • Handling of webhook failures and transaction drop-offs I work with clear daily progress updates and honest scoping. Please share your technical brief and I can get started right away. Best regards, Gagan

@rohitpatidar001

Hello, I’m interested in your FinTech Real-Time Payments MVP. I’m a Senior Java/Spring Boot developer with 11+ years of experience building enterprise backend systems, REST APIs, database-driven applications, and financial/payment-related workflows. I have strong experience with PostgreSQL/MySQL, API integrations, authentication/security, webhooks, transaction processing, Docker, and production troubleshooting. • BaaS/payment REST API integrations and webhook processing • Secure payment transaction workflows • PostgreSQL/MySQL data and transaction design • Redis-based caching where appropriate • OAuth 2.0 and secure API communication • Idempotency and duplicate transaction protection • Transaction state management and reconciliation • Reliable webhook processing with retries and failure handling • ISO 20022-based integration work • Audit logging and transaction traceability • Docker/cloud deployment and end-to-end testing • Backend architecture designed for reliability and scalability **Mandatory screening question:** In a previous financial/payment API project, I worked with transaction-oriented APIs where reliability and duplicate processing were important. I designed the transaction flow around persistent transaction states and idempotency so that the same request could safely be retried without creating duplicate processing. I’m available for the 2–3 month milestone-based engagement and would be happy to sign an NDA and review the detailed technical brief.

@ihsan191

Hi there, I specialize in building secure backend systems, and I have extensive experience integrating financial transaction APIs while managing webhook failures effectively. This project aligns perfectly with my skills, and I can deliver the MVP within your timeframe with precision. You’re looking to develop a real-time mobile payment application for the Australian retail market, utilizing NPP, PayTo, and PayID, while integrating third-party BaaS APIs and ensuring robust security measures. I understand the importance of creating dynamic merchant QR codes and deploying end-to-end simulations in the SWIFT/NPP sandbox. I can also ensure that the solution will be scalable and well-documented for future updates. I would love the opportunity to discuss this project further and collaborate closely, as I believe we can achieve great results together. Thank you, Ihsan

@TechWagger2026

As an experienced and versatile FinTech developer, I check off all the boxes when it comes to building your real-time payments app. With a robust track record of over 14 years and more than 416 successful projects under my belt, I've the technical bandwidth to integrate the necessary third-party APIs like Monoova and Zepto, leveraging my expertise in Node.js, Go, or Python. Having also previously built core ledger systems, I know how critical data security and protection are for payment apps, which is why I'm well versed with AES-256 encryption, OAuth 2.0, and device biometric token validation. Lastly, as you rightly seek a cost-effective but highly efficient solution for your venture which I can completely understand as a startup myself in earlier days. This fact empowers me to provide ultimate tailor-made digital products that help businesses grow and stand out online—and this will be no different in our partnership together. For thoroughness sake: about past project handling webhook failures or transaction drop-offs in one of my integrations; all exceptional developments has occurred through constant communication between stakeholders thanks to agile methodologies we apply behind the scenes. Let's move forward with accurate anticipations and define our shared success!

@kausarafridi07

With 15+ years of diverse experience as a Full Stack Developer, I am well-versed in not only the specific technologies you require for your Real-Time Payments App MVP, but also the larger FinTech ecosystem it operates within. Building digital wallets and core ledger systems has been one of my specialties for years, so rest assured you'll have a masterful architect at the helm of your backend development. Additionally, I have previous experience integrating financial transaction APIs into complex web infrastructures, proactively handling webhook failures and transaction drop-offs while maintaining real-time synchronization. In addition to matching your mandatory screening question by showcasing how I overcame API integrations challenges, my skillset extends beyond the purely technical; I have a profound understanding of end-to-end product development that aligns perfectly with your requirements. From idea validation to deployment and growth, I bring comprehensive solutions that ensure scalability while delivering on time and budget. The FinTech industry continues to fascinate me and your project couldn't be more suited to my passion. By selecting me for this project, you choose an expert who can integrate REST APIs flawlessly, design secure backends with encryption features like AES-256, OAuth 2.0 with no compromise made protecting sensitive financial data.