Just in Time vs. Just in Sequence: Optimizing Your Inventory Management

Manufacturers are constantly searching for more efficient, cost-effective ways of operating. When it comes to improving their inventory management and procurement logistics, it’s worth assessing and comparing the Just in Time (JIT) and Just in Sequence (JIS) delivery methods, to see if they offer added efficiencies.

In this post, we’ll break down how Just in Time and Just in Sequence actually work on the floor and how to decide which approach fits where based on your mix, space, and process needs.

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In a Just in Time setup, materials don’t sit around waiting. They show up to the line right before they’re needed i.e. nothing extra, nothing early.

This keeps inventory light and the floor clear. There’s less shelving, less sorting, and fewer workarounds when priorities shift. A part gets used, a signal goes out, and the next one’s on its way. That signal might come from a barcode scan, a digital kanban loop, or even a simple app tied to the build schedule.

It’s a good fit when production runs are stable and timing is predictable. But there’s a catch: if a delivery’s late or a shipment gets missed, there’s no safety net. That’s why most teams apply JIT where it makes sense i.e. on steady SKUs, common parts, or repeatable builds while keeping buffer zones in places that see more variation.

Just in Sequence is a manufacturing process where the parts or components to be assembled are delivered by the supplier directly to the line at the time they are required and in the sequence they are needed.

This form of delivery aims to simplify and speed up the production process by ensuring assembly workers don’t have to choose from different parts, but are able to just pick the next part in the supply queue.

JIS is also known as Sequential Parts Delivery (SPD) or, in the automotive sector, In-Line Vehicle Sequencing (ILVS).

Because the aim of JIS is to ensure parts are delivered to where they are required for assembly, and in the order they are needed, it eliminates the time, resources, and effort traditionally required by warehouse staff to pick and move parts from storage to the line.

For JIS to work effectively, however, detailed communication, planning, and coordination are required so suppliers are able to prepare and ship components at the right time and in the correct order.

The Core Difference

JIT makes sure you’ve got the right part at the right time. JIS adds one more piece: the right order. Both methods aim for smoother flow and fewer storage headaches. Which one makes sense for you depends on how much variation you’re managing and how tightly your line runs.

When to Go JIT and When to Go JIS

There’s no blanket answer. It depends on what you’re building, how steady demand looks, and how tightly your supply chain and line are synced up.

JIT usually works best when:

• Demand is steady and predictable

• You’ve only got a handful of SKUs and not much variation

• Takt time doesn’t bounce around

• You want to cut down on inventory without adding a bunch of extra process steps

• Parts can be dropped off at the line without heavy sequencing or labeling
  

If you’re running the same product day in and day out, JIT keeps things simple. A Kanban loop, a milk run, maybe some light MES triggers and that’s usually enough to keep material flowing.

JIS comes into play when:

• You’re in high-mix, low-volume territory

• Every shift brings new variants like different trims, colors, options

• Changeovers are frequent and you can’t afford mix-ups

• Line-side space is tight, so kits need to show up in the right order

• You’ve got sequencing handled upstream
  

JIS is all about timing and order. To make it work, you’ll need solid BOM data and reliable signals from suppliers ASN and EDI. You’ll see it most in auto plants, electronics builds, or med device lines where one small sequencing error can stall everything.

Mixing Both

A lot of plants end up running a hybrid. Base parts like fasteners, brackets, subassemblies flow in JIT. Option-heavy stuff like interiors, wire harnesses, or cosmetic panels run JIS. The smart move is finding the hand-off point: where variation really starts. Keep everything before that simple; sequence only what you need downstream.

JIT and JIS can deliver big gains, but they also leave little room for error. When something slips, the impact is felt fast. Here are a few of the usual pain points and how manufacturers deal with them:

• Supplier readiness. Not every supplier can jump straight into sequencing or ASN/EDI. Many teams start with a small pilot i.e. one part family, one process to test reliability before expanding.

• System mismatches. If ERP data isn’t lined up with MES or sequencing logic, timing falls apart. Real-time connections between systems, plus the occasional buffer scan, go a long way in keeping flow steady.

• Sequence breaks. One wrong kit can ripple through an entire run if nobody catches it. Point-of-use checks like barcode scans, pick-to-light systems help spot the issue before it snowballs.

• Delivery mistakes. Parts that arrive late or out of place often turn into rework. Simple dashboards at the line let operators confirm loads before they start pulling from them.

• Supplier dependency. With JIS especially, you’re only as strong as your upstream partners. Consistent communication and digital links to suppliers are what keep the system from stalling.

This isn’t theory - plants are already running JIT and JIS to deal with variation, space limits, and the usual push-pull between flow and flexibility. A couple of examples make it clear.

Automotive: Dealing with Variant Overload on Mixed Lines
In auto plants, just-in-sequence isn’t optional in fact it’s survival. OEMs like BMW and Toyota rely on it to feed seats, dashboards, and wiring harnesses in the exact order cars are built. Every vehicle rolling down the line can be configured differently, and without sequencing, the sheer number of trims and options would swamp the floor.

Industrial: JIT to Keep Standard Production Steady
One HVAC manufacturer uses just-in-time to run stable flows of standard parts like brackets, fans, coils. Deliveries hit the line right before use, triggered by digital kanban and scanned in at the station. It keeps stock lean and work areas clear, and because the parts don’t need sequencing, the system stays simple.

Electronics: Blending JIT and JIS for Complex Builds
A U.S. electronics assembler ran into headaches sequencing custom device builds, so they shifted to a hybrid. Base items like PCBs, resistors, fasteners still flow JIT. But for high-variation parts like displays, enclosures, and connectors, they use JIS. Pick-to-light stations and MES rules make sure the right mix shows up at the right time.

Aerospace: Building in Tight Spaces
On aerospace lines, every square foot matters. There’s no room for racks of staged material or rework piles. Boeing suppliers solve this with JIS, sending pre-kitted assemblies sequenced by tail number or order straight to the work cell. Operators scan each kit before install, which cuts clutter and catches mistakes before they turn into scrap.

JIT and JIS only work if the tools on the floor keep up. Operators need something quick, flexible, and easy to adjust when reality doesn’t match the plan. That’s where Tulip fits in.

With Tulip, teams can spin up apps that handle the nuts and bolts of sequencing and flow, like:

• Kitting and sequencing – generate kit labels, automate pick logic, and tie into ASN/EDI

• Line-side checks – scan kits when they land, catch mismatches, confirm before install

• e-Kanban and replenishment – trigger JIT pulls based on takt or real-time WIP

• Exception handling – log and fix breaks in sequence without stopping the line

• Dashboards – track delivery, sequence accuracy, and operator scans as they happen
  

Because it’s no-code, you don’t have to wait weeks for IT or wrestle with rigid MES add-ons. Engineers and production leads can tweak rules, hook into ERP or PLCs, or drop in new digital instructions right when the build mix changes. Minutes, not months.

• JIT is about timing i.e. parts show up when you need them, which keeps inventory lean and flow steady. JIS takes it further by making sure those parts also arrive in the right build order, which helps operators move faster and with fewer mistakes.

• JIT fits when demand is predictable and product variety is low. JIS makes more sense when you’re juggling lots of variants - different trims, options, or configurations where sequence is just as important as timing.

• Most plants end up running a mix. JIT for the basics fasteners, standard subs, common parts. JIS for the option-heavy stuff like interiors, wire harnesses, or cosmetic panels. Decoupling points help you know where one stops and the other starts.

• To make JIS work, you need the foundations in place: clean master data, reliable labeling (QR/barcode/RFID), stable takt time, and suppliers that can handle ASN/EDI. Without that, sequences break.

• The toolset matters, but it doesn’t have to be complicated: MES apps for kitting and sequencing, ERP links for order sync, pick-to-light to guide operators, and dashboards that flag issues in real time.

• Tulip makes it easier because teams can build and adjust JIT/JIS apps themselves - sequencing, kitting, e-kanban, line-side checks without waiting on IT or ripping out existing systems.

• Don’t roll it all out at once. Start with one product family. Measure sequence adherence and first-pass yield. Once it works, expand.