Senior Demand Planner & Buyer — Apparel & Ecommerce

Thrivin; Cardiff; On-site; GBP 42,000 - 64,000; Full time

Job summary

Thrivin is seeking an experienced Demand Planner & Buyer to own the planning, purchasing and inventory management across the business in a fast-growing global ecommerce environment.

You will oversee sales forecasting, open-to-buy management, PO placement, replenishment and inventory optimisation, working closely with product, operations and commercial teams to support trading decisions and future growth.

Qualifications

• 5+ years' experience in apparel planning, merchandising, buying or related field.
• Personally owning an open-to-buy and making commercial buying decisions.
• Hands-on experience creating and placing purchase orders.
• Advanced proficiency in Excel and working with large datasets.
• Experience in high-growth DTC, ecommerce or activewear is advantageous.

Responsibilities

• Own the open-to-buy (OTB) by category, including forecasts, receipt plans and plan vs. actuals.
• Run the bi-weekly replenishment cycle end-to-end, from demand analysis to PO submission.
• Determine newness buy quantities at style, colour and size level to align with launches and targets.
• Own the full purchase order lifecycle: PO creation, submission, amendments, invoicing and ETA tracking.
• Manage inventory across categories to maintain stock health and in-stock rates.
• Monitor inventory performance and identify stock risks, shortages and excess.
• Lead markdown and overstock actions to optimise sell-through.
• Analyse weeks of cover, sell-through, size curves, gross margin and stock health.
• Present planning readouts during weekly and monthly trade reviews.
• Collaborate with suppliers on proforma invoices, MOQs, lead times and delivery timelines.
• Identify discrepancies early and improve planning processes as Thrivin scales.

Skills

Open-to-buy

Purchase orders

Excel

Data analysis

Supplier management

Tools

Claude Code

Claude Cowork

Job description

Thrivin is seeking an experienced Demand Planner & Buyer to own the planning, purchasing and inventory management across the business in a fast-growing global ecommerce environment.

You will oversee sales forecasting, open-to-buy management, PO placement, replenishment and inventory optimisation, working closely with product, operations and commercial teams to support trading decisions and future growth.