Post
Your inbox has 42,000 unread emails.
Somewhere in there is the K-1 your client sent last Tuesday.
Cairn Post watches your firm's inbox, understands what is coming in from each client, pulls the important content out, and sends it to the right place inside the suite, all without anyone on the team triaging the mail by hand.
The Problem
Information arrives faster than anyone can file it.
Documents vanish in threads
Clients forward W-2s buried in reply chains mixed with questions, small talk, and "here u go" messages, and the documents quietly get lost while the surrounding context evaporates.
Context dies in the inbox
When a client calls months later asking "why did you do X?", the answer is sitting in an inbox somewhere, and nobody remembers the email or can find it quickly enough to actually answer the question.
Knowledge walks out the door
The senior partner knows every client's quirks, including who needs reminders, who sends phone photos of documents, and who panics every Q4. When they retire, all of that institutional knowledge leaves the firm with them.
How It Works
Post in four steps
Every incoming email passes through a pipeline built for accounting work, with domain-aware classification that knows the difference between a 1099-NEC and a newsletter without anyone training it on the basics.
Identify
Every incoming email is classified by an assistant with accounting domain knowledge, which determines who sent it, what it is, and why it matters to the firm.
Extract
When documents arrive as attachments, the assistant pulls the key fields, including form type, tax year, amounts, and identifying details, so the firm knows what came in without opening every file.
Route
One-click routing sends each item to the right place in the Cairn suite, with K-1s going to Returns, receipts to Receipts, and IRS notices to Notices, so nothing falls through the cracks.
Learn
Over time, Post builds profiles of how each client communicates, including who responds quickly, who needs reminders, and who sends photos from a phone. That knowledge feeds into Cairn Contacts where it lives for the long term.
Incoming / Today
12 classifiedFW: Here's the K-1 from Chen Holdings partnership
FW: Got this from the IRS - what do I do??
here u go (attached: blurry phone photo)
Can we deduct the new office furniture if we bought it in December?
AI that knows accounting, not just email.
Post does not do generic sorting by importance. It understands that "here u go" with a blurry phone photo is probably a W-2, that a forwarded chain from a client's banker likely contains financial documents, and that an IRS CP2000 is still a CP2000 even when the client's subject line is just "help???"
Every classification carries routing context with it, so each piece of incoming content lands in the right app, against the right client, matched to the right open request inside the suite.
The Differentiator
Post sorts email. Then it learns people.
Over months and years, Post builds behavioral profiles from the email patterns that pass through it, accumulating the kind of institutional knowledge a senior partner spends decades developing.
Responds to document requests within two hours, always CCs spouse on financial matters, prefers phone photos to scans, and gets anxious in Q4 with shorter emails and more follow-ups.
Typically needs three reminders for document requests, sends everything as forwarded chains with attachments buried in threads, and is most responsive on Tuesdays. Business decisions involve their CFO, who is CCed on 80% of financial correspondence.
Asks advisory-level questions frequently, consistently early with documents and sends them unprompted, and communication peaks around quarterly board meetings. Professional tone throughout, and expects detailed responses.
When the founding partner retires, their 30 years of client knowledge doesn't walk out the door.
Cairn Post feeds behavioral intelligence directly into Cairn Contacts, including communication patterns, response habits, document preferences, and relationship signals. Those signals are synthesized into client personality profiles that any team member can access instantly when a question or call comes in.
New hires no longer start from scratch on long-tenured clients. They inherit decades of relationship context from day one, because the firm's institutional knowledge lives in the system rather than in any one person's head.
Feeds into: Cairn Contacts AI client briefs, relationship intelligence, and client personality profiles. The richest data source in the Cairn integration network.
The Ecosystem
The front door to the entire Cairn suite.
Post sees everything coming in and knows where it should go inside the suite. Every other app gets sharper as Post feeds it the right context, and Post itself gets sharper as every app sends classification data back into it.
Tiered Processing
Not every email needs AI.
Post uses a four-tier pipeline that filters out the noise early and saves the heavier analysis for the emails that actually warrant it.
Rule-Based Filtering
Spam, newsletters, auto-replies. Caught and discarded without touching AI.
Lightweight Classification
Quick pass sorts remaining email into signal vs. noise. Client vs. non-client.
Full AI Analysis
Accounting-domain classification for emails that matter. Document type, urgency, routing.
Document Extraction
Attached documents get key fields pulled: form type, tax year, amounts, identifiers.
Post watches. Post understands. Post routes.
Your team decides and acts.
Not an email client. Doesn't replace Gmail or Outlook.
Not an auto-responder. Never sends emails on behalf of the firm.
Not a practice management suite. Focused on intake intelligence, not workflow management.
Capabilities
What Post does
Classification that knows accounting, so it can tell a 1099 from a newsletter without help
Extracts the key fields from K-1s, W-2s, 1099s, bank statements, and receipts
One-click routing to Returns, Docs, Statements, Receipts, and Notices, so nothing gets lost
Learns each client's communication patterns over time, the way a long-tenured staff member does
Tiered processing pipeline that starts with rule-based filtering and only escalates when needed
Gmail and Microsoft Outlook integration through OAuth, with no inbox forwarding required
Feeds client profiles into Cairn Contacts automatically, so the institutional knowledge accumulates
Part of the Stack
Connects to every app in the suite
Cairn Post is the most connected app in the suite, both consuming cross-app data and feeding context back to the rest of the apps in equal measure.
Cairn Contacts
Sends communication patterns, response habits, and relationship signals into client profiles.
Cairn Returns
Routes tax documents (K-1s, W-2s, 1099s) to the correct filing.
Cairn Docs
Auto-fulfills open document requests when matching attachments arrive.
Cairn Statements
Matches forwarded bank statements to the correct client account.
Cairn Receipts
Routes receipt images and expense documents for categorization.
Cairn Notices
Routes IRS and state correspondence to the notice tracker.
Cairn Post is in active development.
The most ambitious tool in the Cairn suite, and the one that ties everything else together. We are onboarding firms individually to make sure every implementation is done right.