Pull your Sesterce expense ledger into your stack

Every Sesterce group is a small ledger: who paid, who joined, what each person's share was, and the net of who owes whom after the app settles it up. That state lives on the server behind app.sesterce.io and is mirrored down to each member's phone or browser. If you want that ledger inside your own budgeting tool, accounting system, or a migration target, the practical job is reading the group cleanly and keeping a copy current as members keep adding expenses — and members add them from anywhere, sometimes offline, sometimes hours apart. That cadence is what an integration has to respect.

For a tool like this there is no bank rail to consent into — Sesterce is a self-contained ledger, not an account aggregator. So the dependable basis is the group owner's own authorization to read their group, and the work is mapping the web app's traffic to a stable connector. Below is what is reachable, how we'd take it, and what lands in your repository at the end.

What the ledger actually holds

Field names follow how Sesterce presents them in the app and its CSV; the exact wire shapes are pinned during the build.

Domain	Where it comes from in the app	Granularity	What you'd do with it
Groups & members	Group creation; members joined without needing an email; access roles (admin, editor, read-only)	Per group, per member	Top-level entity you sync against; map members to your own user records
Operations (expenses)	Each expense entry — payer, amount, label, category, date	Per line item	The core transaction feed for a budget or accounting view
Participation shares	Per-expense allocation — who took part and at what weight	Fractional, per member per expense	Recompute exact debts instead of assuming an even split
Balances & settlements	The computed who-owes-whom after settle-up	Per member pair	Drive reconciliation or hand pairs to a payments step
Categories	User-defined custom categories per group	Per group	Normalize to a chart of accounts or reporting buckets
Currency & conversion	Foreign-currency expenses converted to the group base	Per expense (original + converted + rate)	Keep multi-currency trips reconciling to what members saw
Stats	Spend rolled up by category and by member	Aggregate	Skip recomputation when you only need the summary

Routes to the data

Authorized interface integration (recommended)

Sesterce runs a real web client at app.sesterce.io, which means the group, its operations and the settle-up result are all served as structured responses to an authenticated session. We analyze that traffic under your authorization and build a connector that reads the same surfaces the web app does. Reach is the whole ledger; effort is moderate; durability is good as long as we add a small revalidation step when the app ships a notable update. This is the route that keeps shares, conversion and balances intact.

User-consented session access

Because groups can exist without an email and may be password-protected, access is set up with you during onboarding using the credentials of a group you control. The connector then runs scoped to those groups only. This is less a separate route than how the recommended one is anchored — it's what makes the read authorized rather than assumed.

Native CSV export (fallback)

Sesterce can share a .csv of a group's expenses, and it imports CSV from Splitwise and Tricount too. That file is a fine fallback for a one-off pull, but it flattens shares and the settlement math, and it is manual. We wire CSV parsing into the build as a backstop, not the primary feed.

The recommendation is the interface connector with consented session access as its footing, and CSV kept as a safety net for backfills. That gives you the live ledger with the debt math preserved, and a manual path that still works if a sync window is ever missed.

What lands in your repository

The headline deliverable is code that runs against your authorized group, not a document about it.

Runnable connector source in Python or Node.js: authenticate the session, list a group's operations, pull members and shares, read the settle-up result.
A change-driven sync routine that pulls deltas on a schedule and emits a record whenever a group's ledger moves, so a member adding an expense surfaces downstream promptly rather than on the next manual export.
An automated test harness that exercises the connector against fixture responses, so a field that shifts under you shows up as a failed assertion before it reaches your data.
A normalized schema that keeps original and converted amounts, the rate, and per-member share counts — the things CSV drops.
Then, as supporting material: an OpenAPI-style description of the surfaces used, a short auth-flow report (how the session token/cookie chain works as observed), and interface documentation with data-retention guidance.

Connector sketch

Illustrative — endpoint shapes are confirmed against the live web app during the build, not guessed here.

# Read one authorized Sesterce group and normalize its operations.
# The session carries the consented login set up during onboarding.
import httpx

def fetch_group(session: httpx.Client, group_id: str):
    r = session.get(f"https://app.sesterce.io/api/groups/{group_id}/operations")
    r.raise_for_status()
    payload = r.json()
    return [normalize(op) for op in payload["operations"]]

def normalize(op: dict) -> dict:
    return {
        "id":          op["id"],
        "label":       op.get("title"),
        "paid_by":     op["payer_id"],
        "amount":      op["amount"],            # in the expense's own currency
        "currency":    op["currency"],
        "amount_base": op.get("converted_amount"),  # group base ccy, when converted
        "rate":        op.get("exchange_rate"),
        "shares":      op["shares"],            # member_id -> share count
        "category":    op.get("category"),
        "revision":    op["revision"],          # change key for delta sync
        "updated_at":  op["updated_at"],
    }

def changed_since(ops, cursor):
    # late edits from a previously-offline device sort by revision, not arrival
    return [o for o in ops if o["revision"] > cursor]

Engineering notes specific to Sesterce

Three things about this app shape how the connector is built; we handle each rather than passing them to you as conditions.

Offline-first reconciliation. The app advertises offline use and syncs when a device reconnects, so the same expense can arrive late or be edited after it was first written. We key the sync on each operation's revision and updated timestamp, so a plane-mode edit that lands hours later is picked up once and an untouched row is skipped.
Account-free, password-gated groups. Groups need no email and can carry a password. We set up access with you using a consenting group's credentials and scope the connector to exactly those groups, so it never reaches beyond what you authorized.
Multi-currency fidelity. A trip can mix currencies that Sesterce converts to a base. We carry the original amount, the converted amount and the rate together, so your reconciliation matches the figures members saw rather than re-deriving them with a different rate.

Sesterce is operated by Naiane SAS in France (per its legal notice), and is described in MWM's catalog as privacy-first with no email required. That puts the work squarely under the GDPR, with the CNIL as the supervisory authority and the user's Article 77 complaint right intact. Our footing is the group owner's authorization to read their own group. We log what the connector reads, hold consent records, minimize fields to what your use case needs, and keep group passwords and raw member identifiers out of anything handed back unless you specifically need them. Where a deployment touches personal data of other group members, we work under an NDA and a documented retention window. This is how we operate, not a gate you clear before we begin.

Where this gets used

A household budgeting tool pulls a roommate group nightly and posts each person's net balance into its own dashboard.
At the end of a trip, the connector reads the group, resolves the settle-up pairs, and hands those pairs to a payments step for repayment.
An accounting handoff maps Sesterce's custom categories onto a chart of accounts and emits normalized line items per expense.
A user leaving Sesterce gets every group pulled in one backfill, shares and conversions preserved, ready to land elsewhere.

Engagement

A working Sesterce connector — source you can run, with its sync routine and tests — starts at $300, and you pay only after we deliver it and you're satisfied with what it does. If you'd rather not host anything, the same integration is available as a hosted endpoint you call and pay per call, with no upfront fee. Either way the build runs in one to two weeks, and you bring only the app name and what you want out of its data; access and the compliance paperwork are arranged with you along the way. Tell us the group data you need and we'll scope it: Start a Sesterce integration

App screens

The bill-splitting category shares the same shape of data — groups, expenses, shares, balances — so a connector pattern built for one usually generalizes. Named neutrally for context:

Splitwise — the widely used group-expense ledger with friend balances and settle-up history.
Tricount — trip and group expense tracking popular in Europe, CSV-friendly.
Settle Up — group expenses with multi-currency and a web companion.
Splid — account-free trip splitting with 150+ currencies and PDF/Excel export.
Cino — splits via shared virtual cards linked to members' own bank cards.
SplitterUp — full-featured splitting with receipt scanning and smart settlements.
Kittysplit — browser-based shared tabs with no app install.
Venmo Groups — expense tracking layered onto a P2P payment app.

Questions integrators ask

Sesterce works offline and syncs when a device reconnects. How do you capture a member's edits without missing or duplicating them?

The connector reads each operation's server-side revision and updated timestamp rather than trusting insert order. When a device that was offline on a flight reconnects and pushes its edits, the next sync pass picks them up by comparing revisions, so a late edit lands once and an unchanged expense is skipped.

Our groups have no email attached and some are password-protected. Can you still read one specific group's ledger?

Yes. Sesterce groups work without an account and can carry a group password, so access is arranged with you during onboarding using a consenting group's credentials. The connector is scoped to exactly the group or groups you authorize and reads nothing else.

We already export CSV from Sesterce. Why pay for an integration instead?

The CSV holds expense rows but flattens shares, currency conversion and the computed who-owes-whom settlement. A connector keeps each operation's payer, per-member share counts, original and converted amounts and the running balances, and it runs on a schedule instead of a manual download. CSV stays as a fallback path in the build.

Which data regime covers what we pull from Sesterce, and who is the operator?

Sesterce is operated by Naiane SAS in France per its legal notice, so the GDPR applies and the CNIL is the supervisory authority. We work against a consenting account, log what is read, minimize fields to what your use case needs, and keep group passwords and member identifiers out of anything we hand back unless you need them.

Sources and method

Checked in June 2026 against the Play Store listing, the Sesterce site and web app, and the company's privacy and legal pages, cross-read with the MWM app catalog and current category roundups for the related-app set. Citations:

Assessment by OpenFinance Lab, 2026-06-01.

App profile (recap)

Sesterce – Share Expenses (package io.sesterce.androidapp, also on iOS as Sesterce – Split expenses) is a shared-expense and bill-splitting app for friends, couples and roommates. It records group expenses, supports custom categories and participation shares, converts foreign currency, shows stats by category and member, and computes who pays whom. Groups need no email and can be password-protected; the app works offline and syncs later, and offers CSV export of group expenses plus CSV import from Splitwise and Tricount. Operated by Naiane SAS, France, within the MWM catalog. Figures such as ratings and the last-update date are per the store listing and not restated here as fixed values.