Put-to-Light

Put-to-light (PTL) is a light-directed warehouse technology that guides operators where to place an item after it has been retrieved — the functional inverse of pick-to-light, which guides operators where to take from. It is the automation layer that resolves the sortation step in a Batch Picking workflow: a picker collects items for many orders in a single warehouse pass, and put-to-light then directs them to place each item into the correct order bin or cubby without paper or memorisation.

How it works

The operator workflow is as follows: the operator scans an item barcode; the light module at the correct destination bin illuminates (typically showing the quantity to place and using colour to indicate placement type); the operator places the item; they press a confirmation button or break a sensor; the system sends a real-time confirmation event back to the Warehouse Management System (WMS) or Warehouse Execution System (WES); the operator scans the next item. (AutoStore, dclcorp.com — undated evergreen page, fetched 2026-07-05)

Put-to-light systems integrate with WMS and ERP via bidirectional REST API: the WMS sends light-on commands specifying location, quantity, and colour; the device sends confirmation events back in real time. (Voodoo Robotics, voodoorobotics.com — undated, fetched 2026-07-05)

Coloured lights distinguish different placement instructions, reducing cognitive load and operator search time. (AutoStore, autostoresystem.com — undated, fetched 2026-07-05)

Primary use case: batch-to-sort

The dominant application in ecommerce fulfilment is the batch-to-sort (or zone-batch) workflow:

1. Pickers collect multiple orders simultaneously by SKU in a single warehouse pass — Batch Picking
2. At the put wall or sortation station, put-to-light directs each item into the correct order bin or cubby
3. A second team on the other side of the Put Wall packs completed orders

"One of the most popular applications for put-to-light systems is sorting of batch picked products into individual orders." (DCL Logistics, dclcorp.com — undated, fetched 2026-07-05)

Sellercloud describes a related pattern: zone batch picking, where a warehouse is divided into zones, pickers batch within their zone, and put-to-light performs the cross-zone sortation. (Sellercloud, sellercloud.com — undated, fetched 2026-07-05)

Put-to-Light vs. Put Wall — not interchangeable

A common source of confusion in vendor pitches: put-to-light is the light-guided software system (hardware modules + controller + WMS integration); a Put Wall is the physical shelving structure (cubbies, slots) in which PTL light modules are typically embedded. Choosing between them — or combining them — should start from identifying where errors and delays arise in a specific operation, not from the technology. (Electrotec SC, electrotecsc.com — undated, fetched 2026-07-05)

Performance benchmarks

[!unverified] All accuracy and throughput figures below are vendor-cited. No independent, peer-reviewed study (e.g. Fraunhofer, MHI, WERC) was surfaced in 2024–2026 searches. Treat as directional.

• Order accuracy: PTL systems consistently deliver ≥99.9% order accuracy vs 96–98% for manual paper-based picking. (as-of undated; AutoStore, autostoresystem.com — fetched 2026-07-05)
• Throughput: 300–500 lines per operator per hour in general environments; rising to 400–600 with horizontal carousels or VLMs in pharmaceutical/electronics settings. (as-of undated; Numina Group, numinagroup.com — fetched 2026-07-05)
• Improvement vs baseline: 30–50% throughput improvement over paper-based or RF-scanner picking in high-velocity repetitive environments. (as-of undated; AutoStore, autostoresystem.com — fetched 2026-07-05)

• Training time: 30–45 minutes to train an operator on a well-configured PTL system. (as-of 2025-03-27; Aliter Business Services, youtube.com/watch?v=Eac8Za0hjyE — fetched 2026-07-05)
• Sorting speed: An automated put wall with PTL allows a single operator to sort up to 3× faster than manual sorting. (as-of undated; unknown channel, youtube.com/watch?v=QZvq-FjGwJE — low confidence; unattributed benchmark)

Throughput by directing technology

Honeywell Intelligrated identifies three directing technologies for put-wall operation, ranked by throughput: RF handheld (lowest) → voice-directed (mid) → put-to-light (highest). (as-of 2021-11-04; Honeywell Intelligrated, youtube.com/watch?v=CbvIcWNIRak — fetched 2026-07-05)

Vendor landscape

The put-to-light / pick-to-light market's major vendors include: Daifuku, SSI Schäfer, Dematic, Honeywell Intelligrated, KNAPP, Kardex Group, Vanderlande, Lightning Pick Technologies (Matthews Automation), Swisslog, Murata Machinery, Bastian Solutions, Falcon Autotech. Top-10 players hold more than 50% of the warehouse automation market. (as-of 2021-08-11; BusinessWire/ResearchAndMarkets — stale-risk applies)

Notable vendor developments (2025–2026)

• Dematic broke ground in January 2026 on a USD 150M expansion of its Grand Rapids, Michigan plant — 200,000 sq ft of new capacity for Automated Storage and Retrieval System (AS/RS) and PTL systems, creating 300 jobs and cutting North American lead times by ~⅓. (as-of 2026-01; Spherical Insights secondary source, fetched 2026-07-05 — original Dematic press release not fetched)
• Honeywell Intelligrated Momentum WES: just-in-time cubby allocation assigns orders to the first available put wall cubby, even across multiple put walls, to prevent idle locations and maintain throughput. (Honeywell Intelligrated, youtube.com/watch?v=CbvIcWNIRak — 2021; product page confirms active product line)
• Lightning Pick (Matthews Automation): integrates with auto baggers, WMS, WES, WCS platforms; 1,000+ installations worldwide in retail, ecommerce, 3PL, pharmaceutical, grocery, cosmetics. (as-of 2020; Lightning Pick — stale-risk)
• Falcon Autotech: PTL system designed specifically for fashion retail and 3PL store-order fulfilment scenarios with high SKU counts and partial-carton processing requirements. (Falcon Autotech, falconautotech.com — undated, fetched 2026-07-05)
• Dematic Next Generation series: fully customisable PTL, scalable, integrates into most existing WMS and ERP processes. (Dematic, dematic.com — undated, fetched 2026-07-05)

Case study: cabi (fashion retailer) — 2026

Fashion brand cabi relocated its distribution centre from California to Indianapolis in 2024–2025 and implemented a put wall system. The new facility separates operations into three distinct stages: (1) batch picking by SKU, (2) sorting at the put wall using put-to-light into cubbies (one cubby per order), (3) packing by a second team on the wall's other side.

The put wall system was designed and built by integrator Systems in Motion, which also integrated a Warehouse Execution System (WES) running its KOZ automation software and added a conveyor from pack stations to delivery docks. The full project — from market assessment through relocation and facility opening — was completed in 12 months. (DC Velocity, dcvelocity.com — published 2026-01-18; Alpine Supply Chain Solutions, alpinesupplychain.com — undated)

[!unverified] Quantitative productivity improvements (30% delivery improvement / 40% transit time / 50% pick line productivity) appeared in a search engine snippet from the DC Velocity article. These figures could not be independently confirmed as the full article may be behind a paywall. Filed as unverified until confirmed.

Market size

Drivers cited for market growth: e-commerce expansion, warehouse automation adoption, retail sector demand. Expanding addressable markets: cold storage and food industry (GlobeNewswire, 2024-08-23). Trend signals for 2025–2026: AI integration, enhanced sortation, greater flexibility for diverse product types (Future Market Insights, futuremarketinsights.com — undated; low confidence — market report summary language only).

Fashion/apparel relevance

Fashion and apparel retail is identified as a high-ROI vertical for PTL because high SKU counts and size/colour variants create maximum mis-pick risk in manual workflows. Falcon Autotech specifically designed its PTL offering for fashion retail store-order fulfilment (partial quantities from inbound cartons of multiple SKUs). (Falcon Autotech, falconautotech.com — undated, fetched 2026-07-05)

AutoStore notes that integration of AutoStore GTP + PTL + Swisslog SynQ WMS can process over 25,000 daily orders. (as-of undated; AutoStore — vendor claim, no named client; low confidence)

Key terms

Term	Meaning
PTL	Put-to-Light — the light-directed system
Pick-to-Light (PTL/P2L)	Light system guiding operators to retrieve items (inverse of put-to-light)
Put Wall	Physical shelving structure with cubbies in which PTL modules are typically embedded — see Put Wall
Batch-to-sort	Workflow: batch pick by SKU across many orders, then sort to individual order bins at a put wall
Zone controller	Hardware unit controlling light modules in a defined sortation zone; single point of failure if not backed up
WES	Warehouse Execution System (WES) — layer between WMS and hardware that orchestrates real-time PTL commands
Cubby	Individual compartment in a put wall assigned to one order
Light module	Illuminated display unit mounted at each cubby/put location; shows quantity, colour, and confirmation button
JIT allocation	Just-in-time cubby allocation (Honeywell Momentum) — assigns orders to first available cubby dynamically rather than pre-assigning at run start

Gaps in current coverage

• No independent benchmarks (Fraunhofer / MHI / WERC) for accuracy or throughput — all figures are vendor-sourced
• No ROI / payback period data with named sources (2024–2026)
• No European-specific adoption data, vendor market share in EU, or regulatory/labour-cost context
• No head-to-head comparison of PTL-at-a-put-wall vs Goods-to-Person (GTP) for the same operation type
• No pricing or TCO data (vendors do not publish)
• Reddit signal: unavailable — reddit-research MCP produced no real data in this run (tool calls: 0); gap logged
• Omnichannel use cases (store replenishment + ecommerce from the same zone) not covered
• BOPIS / click-and-collect PTL use cases not covered