LightSource vs. SourceDay

Where SourceDay is strong: keeping purchase orders true after award

SourceDay's core job is purchase order collaboration, and it does that job well. Every PO line from the ERP shows up organized by status and action needed; suppliers acknowledge orders, propose date, quantity, and price changes, and accepted changes write back to the ERP. Reviewers repeatedly credit that write-back for improving order accuracy, and the supplier side is built for adoption: free for suppliers, no-login interactive emails, EDI, and ERP marketplace listings that carry a 70 percent supplier adoption guarantee.

The ERP relationships are real. Epicor presents SourceDay as the supplier portal for Kinetic, Infor CloudSuite Industrial is a strategic partnership, there is a NetSuite SuiteApp and an Acumatica listing, and the company markets connections to any ERP through API, EDI, or flat file across hundreds of ERP environments. Since late 2024 SourceDay has shipped an AI layer as well: SourceDay Intelligence for risk detection and a set of agents that chase open orders, push new POs, and execute routine supplier-initiated PO changes within buyer-set guardrails. The company reports 52,000 PO changes executed autonomously across 120,000 supplier entities as of May 2026. Those are its own figures, but they describe a production capability, not a roadmap.

Downstream of the PO, shipment visibility, receipts, and invoice-match support extend the same system through delivery. Its case studies report on-time delivery at Ag Leader rising from 76 to 99 percent. For a mid-size discrete manufacturer whose pain is late POs and unacknowledged changes, this is a focused, legitimate product with over a decade of practice.

Where LightSource is the system of record: everything before the PO exists

LightSource covers the work SourceDay assumes has already happened. Before a PO can be cut, someone decided who makes the part and at what price, and that decision is the whole product: AI ingestion turns Excel, PDFs, and drawings into a revision-managed item master; nested BOMs carry snapshots, diffs, and cost roll-ups; RFQs go out at part level with the current drawings attached; and award scenarios turn quotes into tracked contracts whose pricing exports to the ERP.

Cost breakdowns are the sharpest contrast. SourceDay compares what suppliers type into its portal forms, side by side. LightSource is the only sourcing solution with true flexible cost breakdowns: category-specific bid sheets for each event, plus AI that normalizes any quote format so bids are comparable line by line, including tooling, packaging, and logistics. SourceDay's RFQ module is real, and for simple catalog re-buys it is convenient, but it has no item master behind it, no revision linkage, no cost breakdowns, and no scenario modeling.

There is also nothing on the SourceDay side for finding suppliers you do not already trade with. Its 100K+ activated suppliers are your existing vendors working your POs, while LightSource's network of 20,000 live suppliers supports AI capability-based discovery, free supplier onboarding in under 30 minutes, and Excel round-trip quoting. Manufacturers like BRP, Canada Goose, and Infinite Machine run this pre-award work in LightSource today.

Two units of work: the part and the purchase order line

The clearest way to understand these two products is the object each one is built around. SourceDay's object is the purchase order line: everything in the product exists to keep that line true between the ERP and the supplier as dates, quantities, and prices move. LightSource's object is the part: a revision-managed item that accumulates drawings, quotes, cost breakdowns, awards, and price history across its life. Neither object substitutes for the other. A PO tool has nowhere to put a revision B drawing or a tooling amortization line, and a pre-award system of record is the wrong place to acknowledge shipments.

The architectural histories follow the same split. SourceDay was founded in 2013, raised a $31.5M Series C led by Norwest in 2022, and has been adding AI onto its PO platform since late 2024; the agents are in production, but the foundation is a collaboration portal. LightSource emerged in 2025 with venture backing co-led by Lightspeed and Bain Capital Ventures ($33M), was named a Gartner Cool Vendor in 2025, and was built AI-native from the start, with AI embedded through ingestion, event setup, bid analysis, and awards.

In our assessment SourceDay sits with supply-chain execution and collaboration products rather than with strategic sourcing systems, and the product's own language agrees: parts, production lines, and, by the company's own count, $18 billion of direct spend managed through the platform in 2025. That is the right category for it, and it is a different category from ours.

Running LightSource and SourceDay together

The handoff between the two is clean because it happens at a real artifact: the awarded purchase order. LightSource runs spec through award. It ingests the BOM, sends part-level RFQs against current drawings, normalizes cost breakdowns, models award scenarios, and exports awarded pricing to the ERP through its GraphQL API or flat files. When the ERP cuts the PO, SourceDay's territory begins: acknowledgment, date and quantity changes, expedites, shipment visibility, and keeping ERP dates true through delivery. An ERP-centered stack with a sourcing system of record upstream and a PO collaboration layer downstream is a coherent architecture, and manufacturers in LightSource's customer profile already run this pattern.

The one seam to manage is where RFQs live. If your team runs LightSource, SourceDay's RFQ module will mostly sit unused, and for engineered components that is the right outcome: quoting a machined part without the revision-managed drawing and the cost breakdown is how pricing errors reach the ERP in the first place. Simple catalog re-buys that your buyers already handle inside the PO workflow can reasonably stay there.

What public reviewers say

LightSource holds a 4.9 out of 5 rating on G2 across roughly 11 reviews; SourceDay holds 4.3 out of 5 across 58 reviews. SourceDay's review base is roughly five times larger, so the two averages come from very different sample sizes and should be read with that in mind.

A note on method: G2 blocks automated access to its pages, and the archived copies of SourceDay's G2 review page do not preserve the review text itself, so we could not verify SourceDay reviewer quotes word for word. Rather than reproduce text we cannot verify, we summarize the recurring themes below and encourage you to read the G2 and Capterra pages directly (Capterra rates SourceDay 4.7 out of 5 across 27 reviews).

The praise is consistent and deserved: reviewers describe SourceDay as easy to learn and easy to train suppliers on, credit the ERP write-back for improving order accuracy in their systems, and value having one place to see all purchasing activity instead of digging through email threads. The recurring criticisms are also consistent: suppliers who do not log in regularly still end up being chased by email, several capabilities reviewers wanted turned out to be separately priced add-on modules, reporting options are limited, and one NetSuite reviewer noted that RFQ results could not sync to purchase contracts.

LightSource's G2 base is small but specific. A G2 reviewer (Mid-Market, 2024), a vice president of supply chain, wrote: "Having the cost and quoting information in a single location helps with rapid product launches and better visibility for our leadership group." Another G2 reviewer (Mid-Market, 2024) was candid about the tradeoff that comes with any supplier-facing tool: "The biggest challenge of LightSource is just getting the suppliers to try it. Once they try it --- they're also hooked. I've had a bunch of suppliers ask me about how to get access for their own procurement team. It's a great sign!"