How fast can you ship an MVP?

21 calendar days from kickoff to production deploy on the 21-Day MVP path. Custom Software builds run 6 to 26 weeks depending on scope.

How much does an MVP cost?

21-Day MVP from $5,000 USD. Custom Software Development from $11,000. AI Development from $7,000. Final quote depends on scope and integration count.

What stack do you use?

Default stack: Next.js, TypeScript, Node.js, Python, PostgreSQL, AWS, Stripe, Clerk, OpenAI, Anthropic Claude.

What services does Parallel Loop offer?

Three service lines: 21-Day MVP Development (from $5,000), Custom Software Development (from $11,000), and AI Development and AI Agents (from $7,000). Within these, 11 specialised service pillars including mobile app development, ecommerce, automation, CRM integration, cloud DevOps, and enterprise solutions.

How is the 21-Day MVP different from Custom Software?

The 21-Day MVP is productised with fixed scope, fixed price, and fixed 21-day timeline. It fits single-workflow products with off-the-shelf integrations. Custom Software is bespoke, sprint-based, and runs 6 to 26 weeks for products with multiple workflows, regulated scope, or enterprise integrations.

What stacks do you support?

Default stack: Next.js, TypeScript, Node.js, Python, PostgreSQL, AWS, Stripe, Clerk, OpenAI, Anthropic Claude. We can work in Java, .NET, Go, Ruby, PHP, Swift, Kotlin where the existing landscape requires it.

Do you offer AI development separately?

Yes. AI Development and AI Agents is a separate service line covering chatbots, generative AI, machine learning, computer vision, NLP, and AI consultation. From $7,000 for a chatbot MVP up to $35,000+ for a custom AI platform.

What is included in pricing?

Working software, full source code, CI/CD pipeline, staging plus production environments, runbook, monitoring setup, dual on-call cover for 2 weeks post-launch. We do not charge separately for architecture, design, or QA. They are part of every engagement.

Can you handle compliance and security?

Yes. We build HIPAA, PCI DSS, SOC 2 Type II, GDPR, ISO 27001, NERC CIP, IEC 62443 architecture where the build requires it. We do not issue audit certificates. We build the architecture and evidence collection that supports your audit firm.

Do you offer maintenance after launch?

Yes. Maintenance retainer from $2,200 per month. On-call cover, dependency upgrades, small features, security patching. SLA-backed. We do not require a retainer to do a build; we offer it as an option.

How fast can you start?

Typically 2 to 4 weeks from scoping call to kickoff. We do not double-book the team.

What is the average engagement length?

21-Day MVP: 21 calendar days. Custom Software: 6 to 26 weeks. AI Development: 4 to 20 weeks. Maintenance retainers run month to month.

How do I know which service line fits?

Book the free 45-minute scoping call. 30 minutes on your build, 15 minutes on which path fits. We tell you at the call if your build does not fit our service lines.

Why not use ChannelAdvisor, SellerCloud, or other off-the-shelf?

Off-the-shelf connectors win when your channel mix is standard and your SKU count is moderate. Custom wins when you have unusual channels, complex per-channel pricing logic, or are building a SaaS product yourself. We assess at scoping and recommend off-the-shelf when it fits.

What is the single source of truth?

Usually your ERP (NetSuite, Brightpearl, Cin7, Linnworks) or Shopify if you do not have an ERP. The source of truth holds canonical inventory, pricing, and listings. Channels are downstream. We do not let channels drift the source-of-truth data.

How do you prevent overselling?

Reserved inventory when an order is in flight. Optimistic locking on stock decrements. Channel-priority logic (e.g., reserve more for Amazon than eBay if Amazon penalises stockouts harder). When overselling does occur, we have a refund-or-rebook workflow.

Can you handle multi-warehouse?

Yes. Multi-warehouse with ship-from-store logic, regional fulfillment, and per-warehouse channel routing. Common for sellers using FBA plus their own warehouses plus 3PLs.

What about Walmart Marketplace approval?

Yes. We help with Walmart Marketplace seller application, integration approval, and the ongoing performance requirements. Walmart has stricter performance bars than Amazon and we build to clear them.

Can you integrate with NetSuite, Brightpearl, or Cin7?

Yes. NetSuite (SuiteScript, REST), Brightpearl, Cin7, Linnworks, Skubana, Sellbrite, Veeqo. Two-way sync with reconciliation. ERP-as-source-of-truth pattern.

What about international and multi-currency?

Yes. Multi-currency listings, FX handling, per-region tax, VAT, GST. Multi-region inventory routing. Channel auth per region (Amazon EU vs US are separate developer relationships).

Marketplace Connectors

Marketplace Connectors. Sync inventory, orders, and listings across every channel.

Multi-channel marketplace connectors that sync inventory, orders, and listings across Amazon, eBay, Walmart, Etsy, Shopify, BigCommerce, TikTok Shop, and your ERP. Real-time reconciliation, overselling protection, and per-channel pricing strategies. Custom builds where off-the-shelf connectors do not fit. Shipped in 8 to 16 weeks. USD pricing.

Book a Free Call →See how we work ↗

Tell us your channel mix, SKU count, and current pain points (overselling, channel drift, manual reconciliation). Scoped plan plus quote within 3 business days.

8–16WEEKS TO SHIP

$9.5K+2-CHANNEL SYNC

MultiMARKETPLACE

NoOVERSELL

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How we work

Overview: Three phases from channel API access to multi-channel sync live. We build with reconciliation as a first-class feature so channel drift surfaces fast.
Step 1 — Scope and architecture: Two weeks scoping. Channel inventory and capability matrix. SKU and listing data model. Source-of-truth decision (ERP vs Shopify vs custom). Reconciliation strategy. Per-channel pricing logic.
Step 2 — Build in sprints: 5 to 12 weeks build. Event-driven sync via webhooks and pull-based fallback. Idempotency on every write. Throttling per channel API. Channel-specific quirks handled (Amazon SP-API rate limits, eBay categorisation, Walmart approval flows).
Step 3 — Harden and launch: 1 to 2 weeks hardening plus launch. Reconciliation queue stress test. Overselling scenarios tested (race conditions between Amazon and Shopify selling the last unit). Cutover plan with parallel running before full switch.

Recent ecommerce builds

Recent marketplace and multi-channel builds shipped to production.

ShipLogicUnified multi-carrier shipping

Multi-supplier orchestration with sync, retry, and reconciliation patterns transferable across marketplace channels.

Read case study →

Dutch GoatWarehouse eBay inventory

eBay-integrated warehouse inventory management for multi-channel sellers with real-time stock updates.

Read case study →

Stupel WallArtShopify-Amazon sync

Shopify-to-Amazon sync platform with inventory reconciliation, listing automation, and order routing.

Read case study →

Full library on the case studies page →

What we deliver. Marketplace Connectors

Multi-channel inventory sync

Real-time inventory updates across Amazon, eBay, Walmart, Etsy, Shopify, BigCommerce, TikTok Shop. Single source of truth (your ERP, Shopify, or custom). Reservation handling for in-flight orders.

Multi-channel order ingestion

Orders from every channel land in one place. Channel-specific fields preserved. Fulfillment routing logic. Status updates pushed back to each channel as orders move through fulfillment.

Listings management

Create, update, and delete listings across channels from one source. Per-channel pricing, descriptions, images, categorisation. Bulk operations for catalog-wide changes.

Reconciliation and drift detection

Scheduled reconciliation of inventory and order data per channel. Alerts when a channel drifts from source of truth. Audit log of every sync action for debugging when something goes sideways.

Channel-specific quirks handled

Amazon SP-API throttling. eBay categorisation rules. Walmart Marketplace approval flows. Etsy listing fees. TikTok Shop video requirements. We map and handle each channel's quirks rather than pretending they all behave the same.

Overselling protection

Race-condition handling between channels when the last unit sells in two places at once. Reserved inventory, optimistic locking, and channel-priority logic. Refund or rebook workflow when overselling does occur.

Typical engagement ranges

Single workflow

From $9,500

Sync between 2 channels (typically Shopify plus Amazon, or ERP plus Shopify).
Best for sellers consolidating from manual processes.
8 to 10 weeks.

Multi-system automation

From $21,000

Sync across 3 to 5 channels with reconciliation and drift detection.
Channel-specific quirks handled.
10 to 14 weeks.

Commerce platform build

From $38,000

Full multi-tenant SaaS for marketplace connectors.
Per-merchant onboarding, channel auth, tier-based pricing.
14 to 22 weeks.

Maintenance retainer

From $2,200 / mo

Channel API updates, reconciliation monitoring, oversell alerts, on-call cover.

Indicative USD ranges. Final quote depends on channel count, SKU volume, and ERP scope. Exact scope and pricing locked on the scoping call.

FAQ

Amazon (US, EU, JP, AU, MX, BR), eBay (US, EU, AU), Walmart Marketplace, Etsy, TikTok Shop, Wayfair, plus Shopify and BigCommerce as both channels and source-of-truth platforms. New marketplaces added on request based on API availability.

Need marketplace connectors?

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Marketplace Connectors. Sync inventory, orders, and listings across every channel.

Get started in 60 seconds

Who we've built for.

How we work

Recent ecommerce builds

What we deliver. Marketplace Connectors

Multi-channel inventory sync

Multi-channel order ingestion

Listings management

Reconciliation and drift detection

Channel-specific quirks handled

Overselling protection

Typical engagement ranges

Single workflow

Multi-system automation

Commerce platform build

Maintenance retainer

FAQ

Need marketplace connectors?