Backend development support connecting a web application’s API to Stripe for usage-based billing. Scope includes configuring API authentication, setting up Stripe checkout for paid access tiers, and testing the payment-to-access flow

OVERVIEW I'm building Inkora, a subscription web app: an AI creative-writing companion for fiction (romance, fan fiction, poetry, general fiction). The React front-end is COMPLETE and will be provided, with clearly marked integration points. I need the backend built, connected, and the full app deployed. This is an 18+ platform with content safeguards. STACK ALREADY IN PLACE - React front-end (provided; single-file app ready to be scaffolded into a project) - GitHub (repo will live on my account) - Vercel (hosting, my account) - Stripe account created - Anthropic (Claude) API key — must live server-side only, never in client code - Domain: inkora.com SCOPE OF WORK 1. Secure AI endpoint — a serverless endpoint (e.g. POST /api/write) that attaches the provided system prompt, calls the Claude API with the server-side key, and returns the text to the front-end. Suggested writing model: claude-sonnet-4-6. 2. Content moderation — screen user input BEFORE the model call and model output AFTER it. Block sexually explicit content and gratuitous graphic gore. Use a inexpensive-model screen (e.g. Haiku) or a third-party moderation API. Log violations; support a warn-then-suspend flow. 3. Auth — your recommendation (Supabase or Firebase preferred). Email + password baseline; Google sign-in if low effort. 4. Database — persist each user's stories (title, genre, full message history, timestamps), characters, and notes. The front-end already models these data shapes. The story's full saved history must be sent with each AI request (this powers in-story continuity). 5. Subscriptions (Stripe) — $10/month, ~$27/quarter, ~$96/year. Free tier: 10 messages per day (make this a config value), resetting every 24h. Gate writing access by subscription status / remaining free allowance. Handle the subscription lifecycle via webhooks. 6. Age-gate persistence — the front-end collects date of birth + an 18+ affirmation; store the affirmation timestamp with the account. Structure it so a third-party age-verification provider can be swapped in later without reworking the flow. I'm open to building on a proven starter/template (e.g. the Vercel AI chatbot template) if it speeds things up — adapting solid existing code is welcome. DELIVERABLES - Deployed, working app (provided front-end + your backend) on my Vercel, repo on my GitHub - All secrets configured as environment variables (never in client code) - Short handoff notes: key rotation, where moderation logs live, how to change config values WHAT I PROVIDE - Complete front-end code, a written backend brief, and the system prompt (shared privately with the selected freelancer) - All accounts (GitHub, Vercel, Stripe, Anthropic) already created and ready TO APPLY, PLEASE ANSWER THESE IN YOUR PROPOSAL: 1. Have you wired Stripe subscriptions with webhooks before? Link or example. 2. How will you keep the API key off the client? 3. How would you implement input + output moderation cost-effectively? 4. Have you deployed serverless APIs on Vercel? 5. Your fixed quote and timeline for this scope. Proposals that don't answer these questions will not be considered.

I’m looking for an experienced Meta/Facebook Ads Manager to set up reliable purchase tracking and launch sales-focused ads for my digital product: a beginner-friendly Raw Feeding Guide for Dog Owners. My product is sold through a website built with Lovable, with Stripe currently handling payments. The guide includes raw feeding education, food reference lists, transition support, printable trackers, and an interactive feeding calculator. My main goal is to generate purchases through Facebook and Instagram ads while making sure Meta can accurately track which ads lead to actual sales. What I Need Help With: 1. Meta Pixel + Conversions API Setup I need someone who can evaluate my current Lovable + Stripe purchase flow and set up the best tracking solution for confirmed sales. This should include: - Setting up or verifying my Meta Business Manager and ad account - Installing and testing the Meta Pixel on my website/sales page - Setting up key website events, such as: - ViewContent - InitiateCheckout - Purchase - Setting up Conversions API (CAPI), if appropriate and supported by my Lovable + Stripe setup - Making sure a successful Stripe payment sends an accurate Purchase event to Meta - Configuring event deduplication so purchases are not accidentally counted twice when reported through both Pixel and Conversions API - Completing a test purchase or other verification process to confirm tracking is working before ads are launched - Explaining exactly how purchase tracking is being handled through my current website and checkout setup I understand that the Pixel tracks actions from a visitor’s browser, while Conversions API can send confirmed purchase information more directly from the website or checkout system. Because my goal is sales, I want a freelancer who understands how to use both correctly when appropriate. 2. Sales Campaign Strategy and Launch Once tracking is set up correctly, I need help creating and launching a Meta sales campaign optimized for purchases. This should include: - Reviewing my sales page and checkout flow before sending paid traffic - Identifying any issues that may prevent conversions - Recommending ad angles and messaging for my target audience - Recommending what creative assets I should prepare, such as video ads, images, testimonials, guide previews, or calculator demonstrations - Building an initial Facebook and Instagram sales campaign optimized for purchases - Creating an audience and testing strategy - Setting up retargeting audiences, when appropriate - Monitoring initial campaign performance and recommending next steps Product Details Product: Digital Raw Feeding Guide for Dog Owners Audience: Dog owners interested in raw feeding, dog nutrition, meal prep, feeding confidence, and premium pet care Format: Online guide and downloadable PDF, with worksheets and calculator access Website: Built using Lovable Payment processor: Stripe Primary goal: Direct purchases through my website Traffic source: Facebook and Instagram ads Ideal Freelancer I’m looking for someone with experience in: - Meta Ads Manager - Facebook and Instagram sales campaigns - Meta Pixel setup and testing - Conversions API setup - Purchase-event tracking and deduplication - Stripe checkout or digital-product purchase tracking - Working with landing pages and conversion optimization - Selling digital products such as ebooks, online guides, memberships, courses, or downloadable resources Experience with Lovable websites, Stripe integrations, or pet/dog-related products is a major plus. I am not looking for someone who will simply boost posts or run traffic/awareness campaigns without reliable purchase tracking. I need someone who understands how to connect ad performance to actual sales. Deliverables The selected freelancer should provide: 1. Review of my current Lovable + Stripe website and checkout flow 2. Meta Pixel installed or verified correctly 3. Key events configured and tested, including Purchase 4. Conversions API recommendation and setup, if appropriate for my setup 5. Purchase-event deduplication configured correctly, if Pixel and CAPI are both used 6. Verification that successful purchases are tracked accurately in Meta Events Manager 7. Initial sales campaign strategy and testing plan 8. Facebook/Instagram sales campaign built and launched 9. Recommendations for ad creatives and copy 10. Initial performance review with clear recommendations for next steps 11. A brief screen-recorded walkthrough or written explanation of what was set up, so I understand my account and tracking after the project is complete To Apply, Please Answer These Questions 1. Have you set up Meta Pixel and Conversions API for a digital product before? Please describe one relevant example. 2. Have you worked with a website built in Lovable or a checkout/payment flow using Stripe? 3. How would you verify that a completed Stripe purchase is being accurately reported to Meta? 4. How would you prevent purchases from being counted twice when using both Pixel and Conversions API? 5. Have you managed Meta sales campaigns for ebooks, online guides, courses, memberships, or similar digital products? 6. What would you review on my sales page and checkout flow before launching paid ads? 7. What starting ad-testing budget would you recommend for a new digital product, and how would you structure the initial test? 8. Please include relevant examples, screenshots, or results from purchase-focused Meta campaigns you have managed, with any sensitive client information hidden. Budget and Contract Type I would prefer to start with a fixed-price project for the tracking setup, campaign strategy, and initial launch. Please propose your fixed-price rate and clearly explain what is included. If the tracking and initial campaign are set up correctly and the ads show promise, I may continue with ongoing campaign management and optimization. Important Note I am not expecting guaranteed sales or guaranteed profitability. I am looking for someone who can correctly set up tracking, help improve the sales funnel, launch a thoughtful purchase-focused testing strategy, and make decisions based on real conversion data.

What this is: I'm the founder of a working AI SaaS platform (FastAPI/uvicorn backend, React/Vite frontend, deployed on AWS). The product pipeline is built and live! I need an experienced engineer to build the authentication, payments, and usage-entitlement layer that gates the product behind login and paid usage. You'll work against a runnable stub repository (real routes + data shapes, proprietary internals removed) - so you can build and test the full layer without ever touching the core IP, and afterwards - I will merge your work into the production app! Scope: • Auth (Clerk): signup/login, session lifecycle, backend session/JWT verification, inject a validated `user_id` into protected endpoints. • Payments (Stripe): Checkout for purchasing usage credits, plus a webhook that credits the user's ledger on successful payment. The webhook MUST be signature-verified, idempotent (Stripe retries-credit exactly once), and reconcilable (handle webhook-failed-but-payment-succeeded). • Entitlement ledger (the core): a credit balance per user with atomic check-and-decrement (two concurrent requests must never double-spend) on PostgreSQL. A `check_entitlement(user_id, ...)`gate that expensive endpoints call before doing paid work. • Server-side route gating: enforce entitlement on every paid endpoint (not just hidden in the UI); clean 401/402/403 responses. • Frontend integration (React): login/signup UI, buy-credits/checkout flow, balance display,graceful "out of credits" states, wired to the above. • Tests for the money-critical paths (webhook idempotency, atomic decrement, gating-bypass attempts). Stack you'll work with: Python 3.11, FastAPI, Pydantic, uvicorn (Linux). React + Vite, Tailwind. PostgreSQL. Clerk. Stripe. Who I'm looking for: Someone who has shipped this exact kind of system to production before. In your proposal, briefly tell me: 1. How you ensure Stripe webhook idempotency and handle reconciliation when a webhook fails but payment succeeded. 2. How you'd implement the atomic credit check-and-decrement so concurrent requests couldn't double-spend. 3. A relevant production system you've built (Stripe + auth + usage metering ideally). *I'd much rather a short, specific proposal - than a long generic one!* Working with me: I'm an engaged founder who genuinely enjoys building, and I want this to be a good experience for both of us! I'm responsive, communicate clearly, and I respect your expertise - because you're the specialist here,and I'm hiring you because you know this much better than I do! I'm not a micromanager and I'm not nitpicky - I just want the end results to be solid! I review in milestones, asking questions because I like understanding the work (not because I'm second-guessing you), and I make decisions quickly so you're never stuck waiting on me! The scope is already well-defined (detailed spec + a runnable stub repo on engagement), so you're not pricing around a vague, shifting target - it's a clean, bounded build. I care about getting the money-handling pieces right, and I'm betting you do too - if that resonates, I think we'll work well together! IP / engagement: A mutual NDA + IP-assignment (work-for-hire) before repo access. You build against stubs; you won't receive the proprietary pipeline. Work is milestone-based, fixed-bid preferred. To apply: Answer the three questions above + share 1-2 relevant examples, and ballpark your timeline and milestone structure (suggested: auth → payments+webhook → ledger+gating → frontend → tests/docs)!

Are you a backend engineer who enjoys debugging, improving existing systems, and completing real product features in a fast-moving startup environment? We are building a platform for the foodservice industry focused on bid management, rebates, contracts, invoices, and document automation. We are looking for a backend developer to help us fix, complete, and stabilize several important modules in our application. This will begin as a paid trial project. If the work is completed successfully, there is an opportunity for ongoing development work as we continue to grow. Main Tasks We currently have several backend modules already built, but they are incomplete, buggy, or not working as expected. Your main responsibility will be to review the existing code, identify issues, fix bugs, complete missing functionality, and make sure the modules work properly from end to end. 1. Invoice Management Module We currently have an invoice module, but it is not working as expected and has multiple bugs. This module also connects with Stripe, so we need someone who can troubleshoot and complete the Stripe-related backend workflows. Responsibilities may include: Debugging the existing invoice management module Fixing invoice creation, updating, viewing, and status logic Reviewing and fixing Stripe integration issues Ensuring invoice/payment data is handled correctly Improving API reliability, validation, and error handling Testing the full invoice workflow from admin and user perspectives 2. Contracts Module We currently have a contracts module, but it is not fully functional. At the moment, admins are not able to properly create contracts, and users are not able to view or sign open contracts. This module uses DocuSign, so experience with DocuSign or similar e-signature integrations is strongly preferred. Responsibilities may include: Debugging the existing contracts module Fixing admin contract creation workflows Fixing user contract viewing and signing workflows Reviewing and fixing DocuSign integration issues Ensuring contract statuses update correctly Handling permissions and access control for admins and users Testing the complete contract lifecycle from creation to signature 3. Document Classifier Module We have a document classifier module that works in some cases, but it fails when multiple files are loaded through S3 and has additional bugs. We need help stabilizing the file processing and information extraction workflow. Responsibilities may include: Debugging the existing document classifier module Fixing issues with multiple file uploads through S3 Improving information extraction reliability Handling batch file processing correctly Fixing bugs related to file parsing, storage, and classification Improving error handling and logging for failed document processing Testing single-file and multi-file workflows What You’ll Do You will be working primarily on backend development and debugging for an existing application. This is not just new feature development — we need someone comfortable jumping into existing code, understanding how the system works, finding bugs, and completing unfinished backend workflows. Your work may include: Reviewing and debugging existing Nest.js/TypeScript backend code Building and fixing RESTful API endpoints Working with Stripe, DocuSign, S3, and document-processing workflows Improving validation, permissions, error handling, and logging Testing APIs using Postman or similar tools Coordinating with frontend developers to ensure features work end to end Creating or updating backend/API documentation as needed Using Git and our CI/CD workflow for deployment Tech Stack Our current backend stack includes: Nest.js TypeScript REST APIs Stripe integration DocuSign integration S3 file storage Document classification / extraction workflows CI/CD pipelines Postman or similar API testing tools Slack and ClickUp for communication and task tracking Skills We’re Looking For The ideal candidate should have: Strong experience with Nest.js and TypeScript Experience debugging and completing existing backend modules Strong understanding of RESTful API design Experience with third-party API integrations Experience with Stripe is strongly preferred Experience with DocuSign is strongly preferred Experience with S3 or cloud file storage is preferred Ability to troubleshoot complex backend bugs Strong API testing skills using Postman or similar tools Good understanding of authentication, authorization, and permissions Ability to write clean, maintainable code Clear communication and reliable follow-through Comfort working in an agile startup environment Compensation and Trial Period This role will start with a paid trial sprint. Compensation is $100 per completed 2-week sprint, paid after successful completion, testing, and verification of the assigned sprint work. We understand this is modest starting compensation, but we are looking for someone who wants to grow with the company. If the initial work is completed successfully, we would like to continue working together on additional backend features, improvements, and platform modules. There may also be an opportunity for full time employment consideration after a successful trial period, based on performance, reliability, and long-term fit. Why Join Us? Meaningful Product Work Your work will directly improve core parts of our platform, including invoices, contracts, payments, and document automation. Startup Growth Opportunity We are an early-stage company building in the foodservice bid and rebate space. The right person can grow with us as the platform expands. Real Ownership You will not just be assigned small isolated tasks. You will help complete important backend modules that are central to the product. Flexible Collaboration We use Slack and ClickUp to manage tasks and communication. Standups may be scheduled as needed, and we work in an agile sprint-based structure. How to Apply Please apply with: A brief summary of your backend experience Your experience with Nest.js and TypeScript Any experience with Stripe, DocuSign, S3, or document processing Examples of backend modules or integrations you have built or fixed Your availability for a 2-week sprint Confirmation that you are comfortable working on a paid trial sprint with the possibility of ongoing work We are looking for someone who can start by helping us fix and complete the invoice, contracts, and document classifier modules. If the work goes well, we would like to hire you for additional backend development work as we continue building the platform.

We need a freelancer to set up and integrate Calendly, Stripe, Zoom, Zapier, and Jotforms for our healthcare business. The work includes configuring each tool, connecting them smoothly, and ensuring everything runs reliably. You should be comfortable handling healthcare-related workflows and troubleshooting any issues that arise. This is a small, part-time project for someone who can deliver a clean, functional setup.

Senior WordPress + SuiteCRM Developer (Ongoing Maintenance & Emergency Support) Overview We are looking for a highly experienced WordPress and SuiteCRM developer to provide ongoing maintenance, troubleshooting, and technical support for an existing business website and CRM ecosystem. This is not a new website build. Our platform relies on WordPress, SuiteCRM, payment processing, API integrations, automation workflows, and customer communications. We need someone who can quickly diagnose issues, implement fixes, perform updates, and help ensure our systems remain stable and operational. The ideal candidate is proactive, responsive, and comfortable working with complex integrations between WordPress, SuiteCRM, Stripe, email systems, and third-party APIs. Responsibilities * Troubleshoot website and CRM issues as they arise * Fix payment processing problems (Stripe and other payment integrations) * Resolve email delivery issues and CRM automation failures * Diagnose and repair API integration problems * Maintain and troubleshoot SuiteCRM workflows, automations, and integrations * Perform WordPress, SuiteCRM, plugin, and system updates safely * Identify potential issues before they impact customers * Monitor site performance and functionality * Maintain backups and recovery procedures * Assist with landing pages, forms, and website enhancements when needed * Coordinate with existing developers and vendors when necessary Technical Requirements Must have experience with: * WordPress * SuiteCRM * WooCommerce * Stripe integrations * API development and troubleshooting * Webhooks * CRM integrations * DNS management * Email deliverability * SMTP configuration * Cloudflare * PHP * JavaScript * MySQL * Website security and performance optimization Ideal Candidate We are looking for someone who: * Responds quickly when critical issues occur * Has experience supporting business-critical websites and CRM systems * Can explain problems and solutions clearly * Is comfortable working independently * Can identify root causes rather than applying temporary fixes * Is available for ongoing long-term support * Understands how customer onboarding, payments, emails, and CRM workflows connect together Important Our business relies heavily on our website and CRM infrastructure for client onboarding, payment processing, compliance services, and customer communications. If a payment gateway stops working, an API breaks, SuiteCRM workflows fail, emails stop sending, or a critical function fails, we need someone who can respond quickly and help resolve the issue. To Apply, Please Include: 1. Examples of WordPress + SuiteCRM projects you have worked on 2. Examples of payment processing or Stripe issues you have resolved 3. Examples of API integrations you have built or maintained 4. Your typical response time for urgent issues 5. Your availability and time zone 6. Whether you offer ongoing maintenance retainers 7. Any experience supporting live production websites with active customers Applications that do not include the requested information may not be considered.

JOB TITLE: Technical Advisor / Fractional CTO (Part-Time MVP Oversight) PROJECT TYPE: Mobile-First Progressive Web App (PWA) – TIME COMMITMENT: ~2 to 3 hours per week (Milestone-based review) DURATION: 4 to 5 Months (Duration of MVP build) COMPENSATION: [Flat Fee Monthly Retainer] ABOUT THE PROJECT We are launching a highly secure, niche online Progressive Web Application (PWA) tailored specifically for medical and healthcare professionals (Doctors, Nurses, EMTs, and Ancillary staff). The core features include a custom schedule/shift-matching query, a hybrid user-verification system (integrating the free US Federal NPI Registry API alongside manual photo badge uploads via Cloudinary), premium tier setups via Stripe Billing webhooks, and third-party chat infrastructure (CometChat/Sendbird). We are hiring an external software development agency to build the MVP. We require an independent, highly skilled Technical Advisor to represent our interests, audit deliverables, and ensure strict code quality. ROLE RESPONSIBILITIES: As our Fractional Technical Advisor, you will act as our "Technical Shield" during the development lifecycle. Your responsibilities will include: Architecture Review: Review the development agency’s proposed database schema (PostgreSQL/MongoDB) and technical architecture blueprint before coding begins to ensure scalability. Milestone Code Auditing: At the conclusion of each project milestone (approx. every 3–4 weeks), log into our private GitHub/GitLab repository to inspect the agency's backend and frontend pull requests for clean documentation, code efficiency, and stability. Vendor Accountability: Attend milestone demo calls alongside the founder to ask technical questions, review functional staging links, and issue a "Pass/Fail" recommendation before milestone payments are released to the agency. Security & Vulnerability Check: Perform a high-level review of data security protocols—specifically ensuring that user-uploaded medical badges, personal identifiers, and Stripe webhooks are completely secure and not exposed via public URLs. REQUIRED QUALIFICATIONS: 5+ years of experience as a Senior Full-Stack Engineer, Technical Lead, or Engineering Manager. Deep production experience building and deploying modern Progressive Web Applications (PWAs). Strong mastery of React/Next.js, Node.js (Express), or Python (FastAPI/Django). Proven experience with third-party API infrastructure drops (specifically Stripe billing pipelines and real-time chat SDKs like Sendbird/Twilio/CometChat). Excellent communication skills and the ability to explain complex technical vulnerabilities or shortcuts to a non-technical founder in simple language. Strict Neutrality Constraint: You cannot be affiliated with or employed by any software development agency bidding on this project. Send resume with expected monthly retainer

Professional Auto Appraisals is seeking an experienced full-stack developer to add a customer onboarding portal to our existing appraisal management application. Important: We already have a working claim management/tracking system. We are not looking for a new CRM, dashboard, or claim management platform. This project is to extend our existing application and automate the client onboarding process. Developer must be comfortable reviewing and modifying an existing codebase. This is not a greenfield project. The selected developer will be extending an existing appraisal management application and integrating new functionality into the current architecture. Project Goal Create a customer-facing portal that allows a client to: * Submit claim information * Upload documents * Complete required agreements * Sign documents through DocuSign * Pay online * Automatically create a claim in our existing application after onboarding is complete Required Workflow Step 1 - Customer Intake Customer completes an online intake form from our website. The form should collect: * Name * Email * Phone number * Address * Insurance carrier * Claim number * Adjuster information * Vehicle year, make, and model * VIN * Mileage * Settlement offer amount * Lienholder information * GAP coverage information * Vehicle photos * Insurance valuation report * Supporting claim documents Step 2 - Document Generation The intake information should automatically populate our existing document templates: * Appraisal Agreement * Letter of Authorization * Right to Appraisal Request (if applicable) Step 3 - Embedded DocuSign Signing We already have a DocuSign account. Requirements: * Use the DocuSign API * Use embedded signing directly within the website/application * Auto-populate templates with intake information * Obtain signatures on the Appraisal Agreement and Letter of Authorization * Return completed documents to the application Step 4 - Online Payment After signing is complete, the customer should pay online. Requirements: * Stripe integration preferred * Payment confirmation stored in the application * Failed payment handling * Receipt generation Step 5 - Claim Creation A claim should only be created in the production claim tracker after: * Required documents have been signed * Payment has been successfully received Once those conditions are met, the system should: * Create a new claim record in the existing application * Attach all intake information * Attach uploaded files * Attach signed PDFs * Set initial status to: "New Intake - Paid" Optional Lead Tracking Prior to payment, the system may maintain a temporary lead record for incomplete or abandoned submissions. These records should not appear as active claims in the production claim tracker. File Storage The system should: * Store uploaded files securely * Store signed PDFs * Associate all files with the claim record * Google Drive integration is preferred if practical with the existing application architecture Technical Requirements Experience with: * Existing application integrations * React * Node.js * Replit deployments * PostgreSQL or similar databases * DocuSign API * Embedded DocuSign signing * Stripe integration * Webhooks * Secure file uploads * Google Drive API * Mobile-responsive interfaces Deliverables * Customer intake portal * Document automation * DocuSign integration * Payment integration * Automatic claim creation * File upload and storage * Status automation * Documentation for future maintenance When applying, please provide examples of: * DocuSign API projects * Embedded signing implementations * Stripe integrations * Workflow automation projects * Applications integrated into existing systems rather than built from scratch The ideal developer understands API integrations, workflow automation, and extending an existing application without replacing current functionality. The ideal candidate is someone who's built: SaaS applications Customer portals Payment workflows E-signature integrations Not someone whose experience is primarily brochure websites or WordPress sites.

Sales Funnel & Payment Architecture: Build a high-converting landing page optimized for a $1 "Tripwire" PDF download. Integrate Stripe or Thrivecart with tokenization enabled to capture credit cards for future 1-click upsells.Subscription Management: Build a recurring $9.99/month billing portal using Stripe Billing or Memberpress. Set up an automated email sequence (via Klaviyo or MailerLite) that automatically feeds AI-generated monthly health briefs and newsletters to active subscribers.White-Label Dropshipping Integration: Connect the website's e-commerce platform (Shopify or Webflow) to white-label fulfillment suppliers (such as Supliful, Zendrop, or Spocket) for automated, on-demand fulfillment of custom-branded supplements, mouth tape, and sleep-tracking watches.Interactive AI Chatbot Integration: Build and embed a voice/video interactive AI avatar (using platforms like Voiceflow, Vapi, or HeyGen) trained explicitly on my custom e-book manuals via vector database/knowledge base uploads. Implement a paywall gating access to the AI for subscribers.Customer Service Automation: Set up an automated customer service triage loop (using Gorgias/ManyChat) to handle fulfillment updates, automated returns routing, and AI ch To prove you read this entire post, start your application with the word 'KNIGHT'