Shopify Custom App Developer – LegitApp API + Webhook Integration

@fullstackdev1

Hi, This is exactly the kind of clean backend integration I specialize in. You don’t need theme edits — you need a secure automation layer between Shopify and LegitApp with proper webhook handling, metafields storage, and automated emails. That’s my expertise. I’ve built Shopify custom apps that: Listen to orders/paid Call external REST APIs (Bearer auth) Process third-party webhooks securely Store structured data in order metafields Trigger transactional emails (SendGrid/Klaviyo) How I’d Build This 1. Order Paid Trigger Detect Authentication Service product Create authentication intent via LegitApp API Save intent ID, submission URL, and status in order metafields Send submission link email to customer 2. Webhook Receiver Secure endpoint with signature validation + idempotency Handle events (submission received, extra photos, completed) Update metafields (status, result, certificate link) Trigger status emails automatically 3. Order Status UI Shopify order status extension block Show live status + certificate download button What You’ll Get Fully automated Shopify → API → Webhook workflow Clean, structured, documented code Secure deployment setup Clear setup instructions I have 14+ years backend experience and have built similar Shopify-to-external-service integrations before. This is a focused integration — I can deliver it efficiently and cleanly. Happy to discuss timeline and technical approach.

@extreamcode

Hi, Your project to seamlessly integrate Shopify with LegitApp's external authentication service is a clear signal of wanting a smooth, automated flow that enhances customer transparency without redundant UIs. With extensive experience in Shopify custom app development and API integrations, I understand the critical role of syncing order statuses and ensuring timely notifications. I will build a secure backend app that handles Shopify order paid webhooks, invokes the LegitApp API to create authentication intents, updates Shopify order metafields with the necessary status and links, and sends customer emails via your chosen email service (SendGrid, Klaviyo, etc.). I also commit to clean, well-documented code alongside setup instructions to simplify maintenance. 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. Have you experienced any challenges with Shopify webhook rate limits or API throttling in past integrations? Best regards, Asad

@Shaiwan

❗❕‼️⁉️ Hello ⁉️‼️❕❗ ❗❕❗❕❗❕ I understand you need a Shopify custom app to integrate orders with the LegitApp API, handle webhooks, update order metafields, and send notifications. I HAVE SOME QUESTIONS REGARDING THE PROJECT SEND ME A MESSAGE FOR MORE DISCUSSION ❗❕❗❕❗❕ What I offer: ⇆ ⇆ ⇆ Build a secure Shopify custom app or backend service ✱ Integrate Shopify orders/paid webhooks with LegitApp API to create authentication intents ✱ Receive and process external webhook events (submission received, extra photos, authentication completed) ✱ Update Shopify order metafields and trigger customer email notifications ✱ Display order status and links inside Shopify order history ✱ Deliver clean, documented code with setup instructions ⇆ ⇆ ⇆ ➷➷➷ I am best candidate with 7+ years of experience in Shopify custom apps, webhook handling, and REST API integrations. I have successfully built similar automated backend workflows for e-commerce clients. Approach: Review Shopify store structure and LegitApp API docs ✱ Develop webhook listeners and metafield updates ✱ Test end-to-end flow including emails and order status display. Let’s chat to clarify workflow details and timelines. Best Regards, Shaiwan Sheikh

@billybryan98

Hello, I hope you’re well. I’m a solo Shopify developer with strong backend experience, focused on building secure, automated integrations rather than front-end edits. I’ve designed and maintained custom apps and backend services that connect Shopify with external APIs, manage webhooks, and keep order data in metafields with reliable email notifications. I work end-to-end, from authentication with bearer APIs to webhook processing and clean, documented code that you can maintain easily. In similar work, I’ve built backend glue that triggers on Shopify order events, creates external intents, stores IDs and URLs in order metafields, and sends status emails automatically as the external service progresses. I handle webhook routing, data persistence, and email delivery using scalable, tested patterns, ensuring data integrity and clear customer communications. I can deliver a secure, scalable Shopify app-backed workflow that updates status and certificates in order metafields, handles external webhooks, and provides easy status visibility in Shopify orders. I’ll provide straightforward setup instructions and ready-to-run code. Best regards, Billy Bryan

@jayprakashyadav

With strong experience in Shopify app development, I can seamlessly integrate your store with the LegitApp API using webhooks, metafields, and RESTful APIs. I’ve built custom Shopify apps that automate workflows efficiently without requiring additional UI changes. My background across Shopify, WooCommerce, PrestaShop, and Magento allows me to design scalable, well-structured eCommerce solutions. I specialize in webhook automation, external API integrations, and email API setup to ensure smooth authentication and fully automated processes. You can expect clean, reliable, and bug-free implementation. I’m available full-time and ready to begin immediately. Thanks, Jay

@johnallenvillan1

Hello, I’ve gone through your requirement for a backend-only Shopify integration that links your store with LegitApp’s authentication flow. The need to orchestrate order-paid events, intent creation, webhook syncing, and metafield updates stands out clearly. I’ve built similar Shopify custom apps where I delivered automated post‑purchase flows connecting Shopify with external verification APIs, including webhook-driven status updates and customer notifications that reduced manual follow‑ups significantly. The deeper challenge here isn’t the API calls themselves but ensuring idempotent webhook handling and maintaining a clean, reliable mapping between external intent states and Shopify order metafields without race conditions. I’ll set up a secure custom app, implement the orders/paid webhook, create intent calls with stored metafields, build a robust webhook processor for all LegitApp events, and integrate email delivery through the provider you prefer. I’ll also add an order‑page UI block reflecting real‑time authentication status. Before starting, I’d like to confirm your preferred hosting setup and email provider to keep the integration consistent across environments. All steps can be delivered in a tight, controlled workflow. Thanks, John allen.

@ravikumarsingh1

Hi! Yes — I’ve built Shopify custom apps that integrate external REST APIs via webhooks and store workflow data in order metafields. For your LegitApp integration, I’d build a lightweight Shopify custom app (Node.js + Shopify API) that: • Listens to orders/paid webhook • Calls LegitApp API (Bearer auth) to create authentication intent • Saves intent ID, submission URL, and status into order metafields • Sends customer submission email (SendGrid/Klaviyo) • Receives external webhooks and updates order metafields accordingly • Triggers email notifications on each status change • Adds an order status UI extension block so customers can view authentication progress and certificate link in their order history The app will be secure, webhook-verified (HMAC validation), and fully documented for deployment. This is a clean backend automation project and can be completed in ~4–6 days including testing. Happy to share examples of previous Shopify webhook + external API integrations.

@aptechzain1

As a top 1% preferred freelancer, I’ve successfully built dozens of Shopify custom apps like the one you need, integrating them seamlessly with webhooks and external APIs. I pride myself on clear communication, on-time delivery, and creating scalable and future-ready code – all crucial to the success of your project. Not only am I well-versed in Shopify custom app development and webhooks, but my REST API integration skills make me an ideal fit for your project. I understand that your workflow is already handled by the external service and this project entails backend integration. That's why I'm confident in delivering a fully automated Shopify → API → Webhook workflow according to your estimated scope. Moreover, my range of other skills like using Shopify metafields, integrating Email APIs (like SendGrid or Klaviyo), and more means I can handle a variety of challenges that come up during projects. My aim is to provide not just a functional solution but also ensure the best experience for both you as my client and ultimately your customers. Let's connect and transform your idea into a powerful digital product together!

@natanr28

HELLO, HOPE YOU ARE DOING WELL! I understand you need an experienced Shopify developer to create a backend app that integrates your Shopify store with the LegitApp authentication API. My extensive background in Shopify custom app development and API integration makes me suitable for this project. I plan to build an automated flow where customer purchases trigger API calls, store necessary data in metafields, and manage webhook events for status updates, ensuring seamless communication between your Shopify store and the external service. I'd like to have a chat with you at least so I can demonstrate my abilities and prove that I'm the best fit for this project. Warm regards, Natan.

@GameOfWords

Shopify + LegitApp Authentication Integration (Intent Link + Webhooks + Status + Emails) I’m a full-stack software engineer with expertise in React, Node.js, Python, and cloud architectures, delivering scalable web and mobile applications that are secure, performant, and visually refined. I also specialize in AI integrations, chatbots, and workflow automations using OpenAI, LangChain, Pinecone, n8n, and Zapier, helping businesses build intelligent, future-ready solutions. I focus on creating clean, maintainable code that bridges backend logic with elegant frontend experiences. I’d love to help bring your project to life with a solution that works beautifully and thinks smartly. To review my samples and achievements, please visit:https://www.freelancer.com/u/GameOfWords Let’s bring your vision to life—connect with me today, and I’ll deliver a solution that works flawlessly and exceeds expectations.

@abdullahbhabh

I can assure you of an optimal solution to integrate your Shopify store with LegitApp's API. For more than a decade, I have provided businesses with digital products that meet their requirements efficiently while adhering to strict timelines and budgets. A recent venture involved creating a secure backend service for a similar Shopify custom app that utilized both Shopify's and external APIs, along with webhooks to automate workflows and update the relevant metafields. I'm confident in replicating this success for your Authentication Service project. Overall, I'm committed to delivering clean, highly functional code that suits your needs perfectly and providing transparent communication throughout the project. Given the opportunity to work on the Backend glue/automation project for your Shopify store integration, I’m ready to bring my skills and expertise on offer airtight security, efficiency and ease of use for transforming it into a fully automated workflow seamlessly integrating Vialect's roses very appropriately. Undoubtedly, we'll make an excellent team!

@KanzahAfaqAhmad

Hi there, I understand you're seeking an experienced Shopify developer to create a custom backend app that seamlessly integrates your Shopify store with the external authentication service API (LegitApp). This project requires expertise in RESTful API integration and handling webhooks, making it a perfect match for my skill set. With over 7 years of experience in Shopify development, I specialize in building custom apps, working with webhooks, and REST API integrations. My proficiency in managing Shopify metafields and email API integration will ensure a smooth and efficient workflow for your project. You can view my portfolio here: https://www.freelancer.com/u/KanzahAfaqAhmad I have successfully implemented similar projects before, and I look forward to discussing how I can help automate your Shopify to API to Webhook workflow. Thank you for considering my proposal. Regards, Kanzah Afaq

@BlocKeyFi

Hi, I understand that you are seeking an experienced Shopify developer to integrate your Shopify store with an external authentication service API (LegitApp). I am confident that I can deliver a seamless backend integration solution for your project. My technical strategy involves building a custom backend app to automate the workflow between Shopify and the external authentication service API. This will include setting up Shopify webhooks for order processing, integrating with the external REST API using Bearer authentication, handling webhook events, updating Shopify order metafields, and integrating email notifications using platforms like SendGrid or Klaviyo. The final deliverables will include a fully automated Shopify to API to webhook workflow, clean and well-documented code, and basic setup instructions for easy implementation. I have a strong background in Shopify custom app development, webhooks, REST API integration, Shopify metafields, and email API integration. I will ensure professional standards, reliable results, and seamless execution throughout the project. I'll send over my portfolio via direct message. Feel free to reach out there. I'm available to dive deeper into your requirements and address any concerns. Best regards, Taneem

@nathanc97

Yes — I’ve built Shopify custom apps integrating external REST APIs with webhook-driven workflows (order automation, status sync, certificate generation, and metafield updates). Proposed architecture: • Shopify Custom App (Node.js + Express or NestJS) • Shopify webhooks: orders/paid • External API integration (Bearer auth) • Webhook receiver endpoint (verified + idempotent handling) • Order metafields storage (intent ID, submission URL, status, result, certificate link) • Email integration (SendGrid or Klaviyo) • App block / order status UI extension to display authentication status Flow: orders/paid → create authentication intent Save intent + URL to metafields Send customer submission email Process external webhooks Update metafields + notify customer Display live status inside order history Key points: • Secure webhook verification (Shopify HMAC + external signature) • Retry-safe processing • Clean service-layer structure • Clear setup documentation Deliverables: • Fully automated Shopify ↔ API ↔ Webhook flow • Clean documented repository • Setup & deployment guide Estimated timeline: 5–7 days. Ready to start immediately and can share example integration patterns upon request.

@amaank66

Hello, This is a clear backend automation project — and exactly the type of Shopify custom app integration we handle. Yes, we’ve built Shopify custom apps using Admin API, webhooks, external REST APIs (Bearer auth), metafields, and transactional email integrations. For your LegitApp flow, we will: • Build a secure Shopify custom app/backend • Listen to orders/paid webhook • Create authentication intent via external API • Store intent ID, submission URL, and status in order metafields • Send customer email with submission link For external webhooks: • Secure endpoint to receive status updates • Map events (submission received, extra photos, completed) • Update order metafields in real time • Trigger customer email notifications • Store and display certificate link We will also add a clean order status UI block in the customer order history showing authentication progress and certificate access. Deliverable: Fully automated Shopify → API → Webhook workflow with clean, documented code and setup instructions. We focus on structured, secure backend builds — not theme-level shortcuts. Best regards, Amaan Khan P. CUBEMOONS PVT LTD.

@murtuza90

I'm Murtuza, a seasoned ????-????? developer with over 13 years in building high-performance applications. I believe my extensive experience would be a great asset for your challenging Shopify project. In my career, I've handled complexities involved in backend integration and RESTful API like your task where a seamless connection between Shopify and LegitApp is crucial. You can trust me to deliver a completely automated flow that connects Shopify to API to Webhook system. Moreover, I have prior experience in developing Shopify custom apps integrating external APIs through webhooks. A recent example includes building an app that integrated Klaviyo for one of my clients. They wanted customers to receive personalized emails based on their shopping behaviors; it was all managed through webhooks generating customer profiles from Klaviyo back to Shopify. I can apply this invaluable experience, customize it to suit your project's needs, and offer you a similar efficient and streamlined workflow, exceeding your expectations. By hiring me for this task, you'll not only get the skills of an accomplished developer but also of an entrepreneur-savvy problem-solver who won't just code blindly but will ensure to add "scalable", "secure", and "efficient" dimensions to the product delivered - because eliminating technical debts is second nature to me. Together, let's transform your vision into a reality that resonates with your mission effectively!

@osmelt5

Hello , Thank you for posting your project. I am an experienced software developer with strong expertise in App Development, Shopify Development and RESTful API. I have successfully completed similar projects and can deliver high-quality, scalable, and reliable solutions tailored to your requirements. I’ve reviewed the attached document and understand the key requirements. I’ll follow up shortly with any clarifying questions if needed. I am confident I can help you achieve your goals efficiently and within your timeline. Let’s connect to discuss the project details, expectations, and next steps. Looking forward to working with you. Best regards, Osmel

@fabians73

Hi there, I’ve read your brief and can build a small, secure Shopify backend app that glues your store to LegitApp with reliable webhooks and order metafield updates. I have practical experience integrating REST APIs, handling Shopify webhooks, storing data in order metafields, and sending transactional emails via SendGrid/Klaviyo. I’ll implement: an orders/paid listener that creates LegitApp intents, saves intent ID/submission URL/status to order metafields, sends the customer an email with the hosted link, and a webhook receiver to process submission/extra-photo/authentication events with metafield updates and customer notifications. I’ll deliver clean, documented code, setup instructions, and a simple order page UI block to display status and certificate links. I can start with a small scoped sprint and deliver a tested integration within the timeline below. Do you have API credentials and test webhook samples from LegitApp I can use to begin development? Thanks, Fabian

@haseebsidd07

Hi There, I understand you're looking for an experienced Shopify developer to build a custom backend app for integrating your Shopify store with an external authentication service API (LegitApp). I can facilitate the seamless automation of your customer flow, ensuring that all API calls, webhook events, and email notifications are efficiently managed. I am Abdul Haseeb Siddiqui, a Shopify developer with over 6 years of experience in RESTful API integration, Shopify app development, and building custom backend solutions. My expertise aligns perfectly with your project requirements. You can view my relevant projects and skills in the following links: https://www.freelancer.com/u/haseebsidd07 I'm confident in delivering a fully automated Shopify → API → Webhook workflow tailored to your needs. Looking forward to contributing to your project! Thank you, Abdul Haseeb Siddiqui