Invoice Submission via WhatsApp, Email and API: How Multi-Channel Intake Works

Accounts payable teams receive invoices from many directions at once: email attachments from established suppliers, WhatsApp photos from field operations, files dropped into shared folders by logistics providers, and system-to-system API calls from integrated procurement platforms. Each channel is a valid way for a supplier to submit an invoice, and each one creates work for the AP team if there is no single place to collect them.

KIP.ai by Axrail consolidates invoice intake across all these channels, so the AP team works from one queue rather than checking multiple inboxes and folders. Axrail is an AWS Premier Partner. This guide explains how each submission channel works, what happens to documents after they arrive, and how automation removes the collection step so the team can focus on extraction, matching and approval.

Why do invoices arrive from so many channels?

There is no single standard for how suppliers submit invoices. The channel a supplier uses depends on their size, their technology and the relationship they have with the buyer. Large suppliers with integrated systems send invoices over API or EDI. Mid-size suppliers typically use email. Smaller suppliers, field agents and casual vendors often reach for whatever is fastest, which is frequently WhatsApp or a shared folder link.

Buyers have little control over which channel a supplier chooses, and asking every supplier to adopt a new portal creates friction, particularly for suppliers who process a small number of invoices with any given buyer. The result is that most AP teams receive invoices from several channels at once, and the first task each day is collecting them all before any processing can begin.

That collection step takes time, and the time compounds at scale. When an AP team processes hundreds of invoices per month, checking multiple inboxes and folders every morning, downloading attachments, renaming files and routing them to the right person is a significant amount of work before a single field has been extracted or matched.

The practical solution is to bring all channels into one system, so the collection happens automatically. The AP team then starts each day with a single queue, organized and ready for review, regardless of where each invoice came from.

Email invoice submission

Email is the most common channel for invoice submission. Most suppliers have email set up, and sending an invoice as a PDF attachment requires no additional technology on either side.

The challenge for AP teams is that email was not designed for structured document intake. Attachments arrive without consistent naming conventions, mixed in with supplier queries, payment reminders and other correspondence. Someone has to identify which emails contain invoices, download the attachments, check that nothing was missed and route each file to the right step in the process. When invoice volume is high, this monitoring and sorting is itself a full-time task.

KIP.ai monitors a designated email inbox and picks up attachments automatically. When an invoice arrives, KIP.ai extracts it from the email, begins the extraction process and adds it to the processing queue. The AP team does not need to log in to the email account, download files or sort them. The inbox becomes an intake point rather than an inbox to manage.

Invoices that arrive with the wrong attachment format, or emails that contain no attachments, can be flagged for the AP team to follow up with the supplier. This keeps the queue accurate without requiring the AP team to check every email manually.

FamilyMart Malaysia uses KIP.ai to receive supplier invoices by email. KIP.ai picks up each attachment, extracts the fields and validates them against expected values before turning the data into an ERP-ready purchase order file. The team processes 2,000 to 3,000 invoices per month this way. Read the FamilyMart Malaysia case study.

WhatsApp invoice submission

WhatsApp has become a practical invoice submission channel in many businesses, particularly where suppliers are individuals or small businesses who communicate primarily over messaging apps. A supplier taking a photo of a printed invoice and sending it over WhatsApp is submitting an invoice. The question is whether the receiving end can process it.

For AP teams without automation, a WhatsApp invoice creates several problems. It arrives on a personal or business WhatsApp account, needs to be downloaded, identified as an invoice, saved and routed manually. The file may be a photo rather than a PDF, which adds an extra step if the extraction tool only handles PDFs. And unlike email, WhatsApp is not naturally organized by subject or sender, so finding all invoice messages requires scrolling through a conversation history.

KIP.ai accepts invoice documents sent over WhatsApp. The supplier sends the PDF or image to the designated WhatsApp number, and KIP.ai picks it up for extraction automatically. The supplier does not need to log in to a portal, create an account or change their submission method. For the AP team, WhatsApp invoices appear in the same queue as invoices from every other channel.

Accepting WhatsApp invoices without automating the collection step creates more work than it saves. The value of accepting this channel comes from connecting it to the same extraction and matching workflow as every other channel, so the submission method does not change the processing steps.

API invoice submission

For suppliers with their own procurement or billing systems, API submission is the most efficient channel. The supplier’s system sends the invoice data directly to KIP.ai over a structured connection. No email, no attachment, no manual step on either side.

API submission is common in larger supplier relationships and in industries where invoice volumes are high and both sides want to minimize the manual touch. A manufacturer invoicing a large retail chain, for example, may send hundreds of invoices per month through an integrated API connection. The buyer receives each one automatically, and the data is already in a structured format, which speeds up extraction and reduces the chance of errors from manual handling.

KIP.ai accepts invoices via API. Suppliers or their systems can send documents or structured data to KIP.ai, and the invoices join the same processing queue as documents from other channels. The extraction and matching steps are the same regardless of how the invoice arrived.

For buyers, API submission also makes it easier to request the documents that are often missing, such as delivery orders, purchase order acknowledgements or supporting attachments, because the connection is already in place and both sides can agree on what to send.

Shared folders, SFTP and other intake channels

Beyond email, WhatsApp and API, invoices also arrive through shared folders and SFTP. These are common in organizations where operational teams collect documents in the field, in logistics businesses where delivery confirmation and invoicing are linked, and in supplier relationships where batch submissions are preferred over individual email sends.

A shared folder intake point works like a monitored inbox: KIP.ai watches the folder and picks up new files as they appear. The supplier or the operations team drops the invoice into the folder, and the collection step is complete. SFTP works the same way for teams that need a more secure transfer method or are integrating with a supplier’s existing file transfer process.

KIP.ai also accepts invoices directly from the ERP. Some AP workflows start with a purchase order in the ERP and need to match incoming invoices against it. Having the ERP as a source means the matching context is always available from the start.

The range of intake channels matters because different suppliers and different parts of the same supply chain will use different methods. A system that only accepts email will still require manual work to process the invoices that come in by other channels. A system that handles all channels removes that work across the board.

The problem with managing multiple channels manually

When each intake channel is managed separately, the AP team has several inboxes and folders to check, different file naming and organization conventions to work with, and no single view of what has arrived, what is in progress and what is waiting. The collection step is not straightforward; it is repeated across each channel and requires judgment to handle edge cases like missing attachments, forwarded emails and duplicate submissions.

There are three common failure patterns in manual multi-channel intake.

Missed invoices. A supplier submits by WhatsApp instead of email, and the invoice sits unprocessed until the supplier follows up at payment time. By then, the payment is late and the relationship is strained.

Duplicate entries. A supplier sends the same invoice by email and WhatsApp, unsure which the buyer prefers. Without a system to flag duplicates at intake, the same invoice may be entered twice. KIP.ai flags duplicate invoice numbers at the extraction stage so the AP team can resolve them before anything is posted.

Channel-specific backlogs. One channel receives a surge of invoices while another is quiet. Without visibility across all channels, the AP team cannot see that work is piling up in one place until the backlog has already grown. A single queue across all channels makes the volume visible and manageable.

Manual collection also makes it harder to measure intake performance. If invoices arrive across five channels and are collected at different times by different people, there is no easy way to know how long the average invoice waited before processing started, or which channel is the most common source of delays.

How multi-channel intake works in KIP.ai

KIP.ai monitors all configured intake channels continuously. When an invoice arrives, whether by email attachment, WhatsApp message, shared folder drop, SFTP transfer, API call or ERP export, KIP.ai picks it up and adds it to the processing queue. The AP team works from one place, and the channel the invoice came from is recorded but does not change the processing steps.

After intake, every invoice goes through the same workflow: extraction, confidence scoring, exception flagging and the maker-checker review and approval sequence. KIP.ai extracts fields such as supplier, invoice number, invoice date, PO number, line items, tax and total, and gives each field a confidence score. Low-confidence fields are flagged for the AP team to check before data is sent to the ERP.

KIP.ai delivers 90% out-of-the-box extraction accuracy on supported documents, and teams spend 80% less time per document (from 15 to 3 minutes). These figures apply to supported document types; accuracy on unsupported or heavily non-standard layouts will vary. The confidence score per field tells the AP team exactly where to focus their review.

Duplicates are flagged at the extraction stage. If an invoice number has been seen before in the same supplier account, KIP.ai flags it for the AP team to review before any entry is created. This catches both genuine duplicates and re-submissions where the supplier resent an invoice that was already in the queue.

What happens after the invoice is received?

Once the invoice is in the queue, the AP workflow continues with matching and approval. KIP.ai compares the extracted invoice data against the corresponding purchase order and delivery order. If all fields match within the configured tolerances, the invoice moves to the approval step. If any field falls outside tolerance, KIP.ai creates an exception and routes it to the maker for review.

After the maker resolves or escalates the exception, the checker approves, and clean, matched data is sent to the ERP. KIP.ai sends data to ERPs such as Xero, QuickBooks, Oracle NetSuite, and many more. It also exports to CSV or Excel for teams whose ERP does not have a direct integration.

The full sequence, from intake across any channel through to ERP posting, runs in KIP.ai without the AP team managing files, inboxes or folder structures. The team’s time goes to reviewing exceptions and approving matched invoices, not to collecting documents.

Who benefits most from multi-channel invoice intake automation?

AP teams that receive invoices from a diverse supplier base, some integrated and some not, benefit most. If some suppliers send PDFs by email, others use WhatsApp and a few have system connections, every channel that is not automated creates a separate collection task.

Teams that process invoices from operational sites, field teams or logistics providers also benefit, because those environments are where WhatsApp and shared folder submissions are most common. The choice is either to bring those channels into the automated workflow or to have a manual collection step for them in parallel.

Volume matters too. At low invoice volumes, the collection step across multiple channels is manageable. As volume grows, the collection step grows with it, and it scales linearly unless it is automated.

You can try KIP.ai on your own invoices with a free trial of 7 days and up to 100 documents. The live demo at demo.gokip.ai uses built-in sample documents and no account is needed. To speak with the Axrail team about connecting your intake channels, visit gokip.ai/contact.

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Frequently asked questions

Can suppliers really submit invoices via WhatsApp?

Yes. KIP.ai accepts invoice documents sent over WhatsApp, in addition to email, shared folders, SFTP and API. The supplier sends the PDF or image to the designated WhatsApp number, and KIP.ai picks it up for extraction automatically. The supplier does not need to log in to a portal.

What file types does KIP.ai accept for invoice submission?

KIP.ai accepts PDFs, scanned images, Excel files and CSV files, among other formats. Documents can arrive by email attachment, WhatsApp message, shared folder, SFTP, API or directly from your ERP. All channels feed into a single queue for extraction and matching.

How does KIP.ai handle invoices that arrive by email?

KIP.ai monitors a designated email inbox. When an invoice arrives as an attachment, KIP.ai picks it up, extracts the fields and line items, scores each field for confidence, and routes it for review and approval. Your AP team does not need to download, rename or sort the files.

What happens if the same invoice is submitted more than once?

KIP.ai flags duplicate invoice numbers for review before any entry is posted. The AP team can confirm whether it is a resubmission or a genuine duplicate and reject it if needed.

Is there a supplier portal for invoice submission?

KIP.ai supports submission without a portal requirement. Suppliers can send invoices by their existing method, whether that is WhatsApp, email or a system-to-system API call. If your process requires a portal, the Axrail team can discuss the right setup for your workflow. Visit gokip.ai/contact to talk to the Axrail team.