Custom API integration and connectors
Your data sits in tools that never talk to each other. We build the connectors that link them to your application, from banking to payroll to your CRM.
What is an API integration, and when should you have one built?
An API integration is a connector built between your application and an external tool, so data moves without anyone retyping it. Off-the-shelf connectors cover standard cases; a custom connector becomes the right answer when your business model does not fit the boxes, when the volume or reliability you need goes beyond what a no-code tool can absorb, or when the data is sensitive and has to stay under your control.
16 families of tools we integrate
Online payments
Collect payments, invoice, handle subscriptions and marketplaces.
See the whole category 3 toolsBanking & open banking
Pull your transactions, reconcile them, trigger transfers.
See the whole category 4 toolsAccounting & invoicing
Link your application to Sage, Pennylane, EBP or Cegid.
See the whole category 3 toolsPayroll & HRIS
Connect Lucca, Silae or PayFit to your HR tools.
See the whole category 4 toolsCRM & sales
Sync HubSpot, Salesforce or Pipedrive with your product.
See the whole category 3 toolsERP & business software
Graft your application onto Odoo, SAP or Divalto.
See the whole category 3 toolsElectronic signature
Get documents signed inside your flow, not next to it.
See the whole category 3 toolsCustomer support
Zendesk, Freshdesk and Intercom wired to your product data.
See the whole category 5 toolsSMS, email & telephony
Send, verify and call straight from your application.
See the whole category 4 toolsCalendars & booking
Sync calendars and automate appointment booking.
See the whole category 4 toolsFiles & document management
Store and find your documents in Drive, SharePoint or Box.
See the whole category 4 toolsCompany data
Prefill a form from a company number, verify a business.
See the whole category 9 toolsFrench open data
Addresses, INSEE, land registry, Legifrance: wiring public APIs.
See the whole category 3 toolsShipping & logistics
Labels, tracking and pickup points across carriers.
See the whole category 5 toolsProductivity
Slack, Notion, Airtable and Jira connected to your product.
See the whole category 6 toolsAI, voice & video
Voice agents, speech synthesis, avatars, language models.
See the whole categoryLess data entry, figures you can trust, teams that move
Engineering in service of a measurable result. A connector is judged on what it takes off your teams' plate.
No more double entry
Data is entered once and propagates. The re-typing time leaves the schedule, and the gaps between your tools go with it.
Figures you can decide on
Your systems say the same thing at the same time. You stop arbitrating between two exports that disagree.
Variance €0.00 · checked on every sync
Your teams keep their tools
Nobody has to switch software for this to work. We connect what exists rather than replace it.
A connector that belongs to you
Code delivered, documented and maintainable. You are locked into neither a black box nor a subscription to a generic connector.
How we run an integration
Scoping
Which flows, what volume, what frequency, which authentication mode. We list the edge cases before writing a line of code.
Development
Typed connector, rate limit handling, retry queue, isolated secrets. A demo every week.
Acceptance testing
Replay on your real data, gap checks, and testing the failure scenarios on the provider's side.
Monitoring
Alerts on sync failures and a connector health dashboard. You know a flow is broken before your customers do.
What we cover, and how we ship
Connectors in production, not tutorials
The questions we get asked about integrations
It depends on the number of flows, the direction of the sync and the quality of the API on the other side. A simple one-way flow, for example pulling bank transactions to display them, costs far less than a two-way sync with conflict handling. We scope the perimeter up front and give you a firm estimate before we start.
A first useful flow usually ships in two to three weeks. A complete chain, with retry handling, monitoring and edge cases covered, is closer to six to eight weeks. The timeline depends less on the API than on how complex your business model is.
For a standard case at low volume, those tools are enough and cost less. Custom development becomes the right call when your business logic does not fit a linear scenario, when you need serious retry handling, when volume makes per-task pricing explode, or when the data is too sensitive to pass through a third party. We also use n8n when it is the right tool: see our dedicated page.
That is planned for. The connector isolates external calls behind a dedicated layer, which confines the impact of a change to a single place in the code. We follow the changelogs of the APIs we integrate and show the last review date on every page.
Yes, and we are asked often. We audit the connector, identify the root cause, fix it, then put in place the monitoring that was missing. We work on code we did not write just as readily as on new projects.
An integration project in mind?
Let's talk. 30 minutes to scope your need, check what the APIs actually allow and tell you honestly what is feasible.
Discuss my project