What Mercury data does Well pull into Pennylane?

Mercury streams transactions, wires, ACH transfers, card payments, and counterparty records to Well over its MCP server. After Well resolves the counterparty and assigns a confidence score, the matched record posts to Pennylane as supplier and customer invoices via email-in, with amount, VAT, and date pre-filled by Pennylane's OCR, with the Mercury event ID preserved on the entry for audit.

What happens to historical Mercury data when I first connect to Pennylane?

Mercury exposes the last three years through its API on a connected account. The window Well actually pulls is configurable from the integration settings page; each record is matched against your existing Pennylane ledger, and re-running the backfill is safe because Well tracks the Mercury record IDs and updates existing Pennylane entries instead of duplicating them.

Does Well handle multi-currency records between Mercury and Pennylane?

Mercury reports a single base currency; Well stores the value verbatim and tags the record so your Pennylane ledger can apply its own conversion rule at posting time. Exchange-rate fields are not synthesised, so the Pennylane entry carries the unchanged Mercury amount and the conversion is owned by the Pennylane accounting policy.

How does Well prevent duplicates when posting Mercury records to Pennylane?

Mercury sends each event with a stable resource ID that Well tracks against the Pennylane ledger. Webhook replays (which Mercury can issue for delivery retries) are recognised by ID and either skipped or used to update the existing Pennylane entry. Distinct records that look similar are caught by Well before posting, with the candidates surfaced in the review queue when confidence is ambiguous.

What happens if a Mercury record fails to post to Pennylane?

When a record fails to post to Pennylane (validation rule, missing field, transient 5xx), Well retries automatically with backoff. Auth failures short-circuit the retry loop and notify the workspace owner; schema rejections are kept on the integration status page with a one-click retry-after-fix action pointing back at the original Mercury record. Nothing silently drops.

How does Well authenticate with Mercury and Pennylane?

Mercury's MCP server handles authorisation directly; Well receives an access token through Dynamic Client Registration and never sees raw user credentials. For the delivery side, Well forwards the reconciled document to your Pennylane email-in address once it clears the matching threshold; Pennylane creates the draft record from it and you confirm and post it. Well holds no write credential to Pennylane. Tokens are encrypted in transit under TLS 1.3. Anything Well holds between Mercury and Pennylane is encrypted at rest and handled in line with GDPR.

Mercury to Pennylane

AvailableNative · MercuryNative · Pennylane

Connect Mercury to Pennylane with Well

Reconcile Mercury transactions and transfers against your open invoices inside Well, then forward the matched documents to Pennylane's email-in inbox for one-click review.

Connect both toolsView all integrations

Mercury

Source

The Mercury integration connects your startup banking to Well via MCP, pulling transactions, balances, and counterparty data into your workspace.

Pennylane

Target

The Pennylane integration creates a bidirectional bridge between Well and your accounting workspace.

Why this pair

Mercury runs in USD on US banking rails; Pennylane runs in EUR for French SMBs.

Connecting them through Well handles the currency conversion, the counterparty resolution, and the matching in one pass inside Well's own ledger. Well matches every Mercury transaction against your existing invoices with the FX rate of the booking date and the original Mercury reference preserved, then forwards the matched document to Pennylane's supplier or customer email-in address so Pennylane creates the invoice with the data pre-filled.

What Well does between Mercury and Pennylane

One-way: Mercury into Well into Pennylane
Sync mode: Real-time MCP push
Events arrive in seconds

Trigger from Mercury

6 events · pick one

Well engine·recipe·When a new transaction posts on your Mercury account

Source

from bank line · live webhook

OVH Cloud SAS

via Mercury

Transaction

When a new transaction posts on your Mercury account

INV-1024 · 22 Apr 2026$1,284.00

Extract

5 fields read from Mercury

5 fields read

CounterpartyOVH Cloud SAS
Booking date22 Apr 2026
Amount$1,284.00
CurrencyUSD
ReferenceINV-1024

Enrich

against your historical record graph

4 fields added

CounterpartyOVH Cloud SAS
Tax idFR22424761419
Ledger account6156 · IT hosting
Match1 candidate invoice

Confidence97%

<55% refused55–85% review≥85% auto-posts

Post

post as supplier and customer invoices

Create a supplier invoice in Pennylane

auto-posted

posted

TypeSupplier invoice
VendorOVH Cloud SAS
Amount$1,284.00
Ledger6156 · IT hosting
Source docattached
Confidence97%

audit linkto Pennylane

Action in Pennylane

1 compatible with this trigger

Create a supplier invoice in Pennylane

Reconcile Mercury transactions to Pennylane ledger lines.

01Featured

Bridge US and FR without CSVs

Connect Mercury banking to Pennylane accounting without the weekly export ritual.

Cross-border close in days

Pre-filled Pennylane drafts with EUR conversion applied keep both jurisdictions current on the same pace.

Accountant-ready draft

Mercury transactions arrive in Pennylane as pre-filled drafts, ready for your accountant to assign and post.

Audit trail intact

Keep the link between Mercury, invoices, and booked entries for compliance reviews.

13 signals and actions across Mercury and Pennylane

When a Mercury account is read
Pulls from the Mercury transactions API. Pulls each Mercury account the workspace holds with its balance, currency, and routing details. Forwarded to Pennylane's email-in with amount, VAT, and date pre-filled by Pennylane's OCR.
Trigger·Account
When a Mercury card charge posts
Pulls from the Mercury transactions API. Captures debit card transactions with merchant and MCC code. Forwarded to Pennylane's email-in with amount, VAT, and date pre-filled by Pennylane's OCR.
Trigger·Transaction
When a wire transfer is sent from Mercury
Pulls from the Mercury transactions API. Tracks outbound wires with beneficiary detail and instruction. Forwarded to Pennylane's email-in with amount, VAT, and date pre-filled by Pennylane's OCR.
Trigger·Transaction
When an ACH payment clears in Mercury
Pulls from the Mercury transactions API. Picks up cleared ACH credits and debits with the company id reference. Forwarded to Pennylane's email-in with amount, VAT, and date pre-filled by Pennylane's OCR.
Trigger·Transaction
When a check is deposited to Mercury
Pulls from the Mercury transactions API. Tracks check deposits with the payer, amount, and clearing date. Forwarded to Pennylane's email-in with amount, VAT, and date pre-filled by Pennylane's OCR.
Trigger·Transaction
When a wire transfer arrives in Mercury
Pulls from the Mercury transactions API. Captures incoming wires with originator, reference, and value date. Forwarded to Pennylane's email-in with amount, VAT, and date pre-filled by Pennylane's OCR.
Trigger·Transaction
When a new transaction posts on your Mercury account
Pulls from the Mercury transactions API. Triggers on every debit or credit posting in a Mercury account. Forwarded to Pennylane's email-in with amount, VAT, and date pre-filled by Pennylane's OCR.
Trigger·Transaction
When a Mercury account's payment details are read
Pulls from the Mercury transactions API. Resolves the account and routing numbers from the Mercury account so a payment instrument can be matched. Forwarded to Pennylane's email-in with amount, VAT, and date pre-filled by Pennylane's OCR.
Trigger·Payment method
Create a supplier invoice in Pennylane
Driven by Mercury transaction events. Well forwards the extracted PDF to Pennylane's supplier inbox; Pennylane creates the supplier invoice with amount, VAT, and date pre-filled.
Action·Invoice

Reference

Field mapping for Mercury → Pennylane

5 fields across 1 record type, open to see the full table.

Transaction fields

5 fields flow from Mercury into Pennylane.

Mercury field	Label		Pennylane field	Label
transaction.amount	Amount	→	amount	Amount
transaction.currency	Currency	→	currency	Currency
transaction.posted_at	Posted date	→	date	Execution date
transaction.bank_description	Description	→	label	Label
transaction.id	Transaction id	→	external_reference	Source id

Connect Mercury and Pennylane in three steps.

1
Connect Mercury
Click Connect with Mercury; Mercury's MCP server handles authorisation through Dynamic Client Registration. Mercury's MCP server registers a read-scoped Well client through DCR; no credential paste, no shared secret.
- AuthConnect
2
Map your accounts
Well discovers Mercury's transactions, wires, ACH transfers, card payments, and counterparty records and the the Pennylane Purchases tab and the customer-invoice collections list. Counterparty proximity, amount, date, and reference drive the match score; lines above 85% post automatically and the rest queue for a one-click sign-off.
- Auto-post above85% confidence
- Overridemanual anytime
3
Connect Pennylane
Click Connect with Pennylane; Well's OAuth proxy handles Pennylane authorisation through Dynamic Client Registration. Pennylane's MCP server registers a write-scoped Well client through DCR; no credential paste, no shared secret.
- AuthOAuth 2.0
- First syncup to an hour

23 agent skills run on Mercury and Pennylane.

Each one answers a question from the data this pair brings in. The required ones return nothing until a source like it is connected.

Needs a source like these

Runway

Know exactly how many months and days of cash you have left.

Cash position

Know exactly how much cash you have, and which accounts it came from.

Payment and invoice lookup

Find what payment settled an invoice, or catch every payment that never got one.

Burn rate

Know what you actually spend each month, averaged over real months.

Cash forecast

See where your cash lands if nothing new comes in.

Cash movement

See the bridge from last month's balance to this one.

Missing supplier invoices

See which suppliers owe you paperwork, before your accountant asks.

Assign missing invoices

Put a name on every settled expense that still has no invoice.

Missing invoice sweep

Walk the whole month-end sweep in one prompt.

Close the books

Drive the month-end close to the point of approval.

Categorize your suppliers

Close the category gaps behind your spend before you close a month.

Answers better with these connected

Cost structure

See where your company's money actually goes, no spreadsheets required.

Receivables aging

See who owes you money, and how long they've been sitting on it.

Bills due

See exactly what's coming due, in what order, and how much cash it adds up to.

Rank clients by LTV

Find out who your best customers really are, ranked by what they've actually paid.

FX exposure

See how much of your cash and receivables sit outside your home currency.

Company profile

Everything you know about one company, in one view.

Missing receipts

Find the bills with no paperwork attached, before an auditor does.

Recurring revenue

Know what you can count on earning each month, averaged over real months.

Invoice fetching agents

See exactly which agents would run, before any of them does.

Convert currencies

Turn mixed currencies into one number you can actually audit.

Connects and checks them

Check your connections

See what is connected, what is syncing, and what is missing.

Connect your bank

Get the bank feed in, and confirm it is really live.

Browse all skills

How Mercury and Pennylane stay secure with Well

Well connects to Mercury through its MCP server, which issues short-lived access tokens via Dynamic Client Registration. Well never holds a long-lived Mercury secret; the server refreshes its own tokens on each session. Anything Well holds between Mercury and Pennylane is encrypted at rest and handled in line with GDPR.

MCP server authEncrypted at restGDPR compliant

Scopes Well requestsmcp.mercury.com/mcp

Read Mercury records
Scoped to transactions, wires, ACH transfers, card payments, and related records. No access to anything else in your Mercury account.
granted
Deliver documents to your Pennylane inbox
Well forwards the extracted document to your Pennylane email-in address; Pennylane reads supplier and customer invoices via email-in, with amount, VAT, and date pre-filled by Pennylane's OCR from it and you review and post. No write credential to Pennylane is requested.
granted
Modify or delete Mercury records
Not granted. Mercury is read-only on Well's side; the source of truth never moves.
refused
Read other workspaces' data
Not granted. A session resolves only to the workspaces your account belongs to, and Well checks that membership before it returns any record.
refused

Disconnect any time from Well settings or Mercury’s admin panel.

Frequently asked questions about Mercury and Pennylane on Well

01What Mercury data does Well pull into Pennylane?: Mercury streams transactions, wires, ACH transfers, card payments, and counterparty records to Well over its MCP server. After Well resolves the counterparty and assigns a confidence score, the matched record posts to Pennylane as supplier and customer invoices via email-in, with amount, VAT, and date pre-filled by Pennylane's OCR, with the Mercury event ID preserved on the entry for audit.
02What happens to historical Mercury data when I first connect to Pennylane?: Mercury exposes the last three years through its API on a connected account. The window Well actually pulls is configurable from the integration settings page; each record is matched against your existing Pennylane ledger, and re-running the backfill is safe because Well tracks the Mercury record IDs and updates existing Pennylane entries instead of duplicating them.
03Does Well handle multi-currency records between Mercury and Pennylane?: Mercury reports a single base currency; Well stores the value verbatim and tags the record so your Pennylane ledger can apply its own conversion rule at posting time. Exchange-rate fields are not synthesised, so the Pennylane entry carries the unchanged Mercury amount and the conversion is owned by the Pennylane accounting policy.
04How does Well prevent duplicates when posting Mercury records to Pennylane?: Mercury sends each event with a stable resource ID that Well tracks against the Pennylane ledger. Webhook replays (which Mercury can issue for delivery retries) are recognised by ID and either skipped or used to update the existing Pennylane entry. Distinct records that look similar are caught by Well before posting, with the candidates surfaced in the review queue when confidence is ambiguous.
05What happens if a Mercury record fails to post to Pennylane?: When a record fails to post to Pennylane (validation rule, missing field, transient 5xx), Well retries automatically with backoff. Auth failures short-circuit the retry loop and notify the workspace owner; schema rejections are kept on the integration status page with a one-click retry-after-fix action pointing back at the original Mercury record. Nothing silently drops.
06How does Well authenticate with Mercury and Pennylane?: Mercury's MCP server handles authorisation directly; Well receives an access token through Dynamic Client Registration and never sees raw user credentials. For the delivery side, Well forwards the reconciled document to your Pennylane email-in address once it clears the matching threshold; Pennylane creates the draft record from it and you confirm and post it. Well holds no write credential to Pennylane. Tokens are encrypted in transit under TLS 1.3. Anything Well holds between Mercury and Pennylane is encrypted at rest and handled in line with GDPR.