WordPress API integration services for agencies

WordPress API integration for your clients’ sites: CRM, payment provider and business tools connected, built by us and delivered under your brand.

Leads land in the CRM, orders reach the ERP, and nobody copies data between tabs. When a sync fails, someone gets an alert instead of finding out a month later.

WordPress site connected to a CRM, Stripe, Mailchimp and an ERP product feed, with an API log

Why integrations cause trouble

  • Clients copy data between systems by hand
  • Leads and orders go missing between tools
  • Connector plugins can’t handle the client’s logic
  • A sync fails silently and nobody notices
  • API keys end up in the theme code
  • Your team hasn’t built API integrations before

An integration is only useful if it works every time, and tells you when it doesn’t.

What we connect

Almost any service with a documented API.

CRMs

HubSpot, Salesforce, Pipedrive and others, with form leads and UTM data sent automatically.

Payments

Stripe, PayPal and regional providers, with verified webhooks for payments and refunds.

Email marketing

Mailchimp, Klaviyo, ActiveCampaign and others, triggered by signups, purchases or forms.

ERP and inventory

Products, stock and orders synced between WooCommerce and the client’s ERP.

Your own endpoints

Custom REST API endpoints for mobile apps, headless front ends and partner systems.

Logs and alerts

Every request logged, with an alert when a sync fails, so you fix it before the client asks.

Integrations we build most often

Each one looks simple in a sales call. The detail below is where the hours go. For the technical side, read our guide to integrating third-party APIs with WordPress.

HubSpot

Form entries become contacts with UTM source and lifecycle stage, and the contact owner is set by region. No duplicate contacts when someone fills in two forms.

Salesforce

Web-to-Lead swapped for the REST API, so custom fields, record types and duplicate rules actually work.

ERP and inventory

Stock and prices pulled from the ERP every 15 minutes. Paid WooCommerce orders pushed back with the client’s SKUs and tax codes.

Stripe and payments

Subscriptions, refunds and failed payments handled through signed webhooks. Card data never touches the WordPress server.

Booking and calendars

Availability read from the client’s booking system, so the site never offers a slot that’s already taken.

Shipping

Live rates and label creation through ShipStation, Shippo or a carrier’s own API, with fallback rates if the API is slow.

What happens when an API call fails

APIs time out, rate-limit and change. Most of the work in a good integration is in handling that.

Queued, not blocking

Syncs run in a background queue (Action Scheduler). A slow CRM never makes a visitor wait on the form or the checkout.

Retries

Failed calls are retried with increasing delays. A short outage on the other side fixes itself.

No duplicates

Each record carries an ID the other system can check, so a retry updates the record instead of creating a second one.

Logs you can read

An admin screen with recent requests, responses and errors. Your team can answer “did that lead go through?” in a minute.

Alerts

If a sync keeps failing, an email or Slack message goes to whoever you choose.

API keys and client data

The parts that matter in a security review.

  • Keys live in wp-config.php or environment variables, never in the theme or in Git
  • Each key gets the narrowest permissions the integration needs
  • Incoming webhooks are checked against their signature before anything runs
  • Only the fields the other system needs are sent, which keeps GDPR reviews short

How we build a WordPress API integration

  1. 1. Map the data

    Which system owns which data, what triggers a sync and what should happen when it fails.

  2. 2. Spec and quote

    We read the API docs, check the rate limits and send a short spec with a fixed price.

  3. 3. Build on sandboxes

    We build on staging with sandbox accounts and test the failure cases, not only the happy path.

  4. 4. Go live and watch

    We deploy, watch the first syncs and hand over docs your team can share with the client. Bugs found in the first 30 days are fixed at no extra cost.

Example: a B2B store connected to HubSpot and an ERP

A typical project for a WooCommerce agency with a wholesale client.

  1. The problem

    Sales staff re-typed every web order into the ERP. Stock on the site was a day behind, and leads from three forms landed in a shared inbox.

  2. What we built

    Stock and customer price lists pulled from the ERP every 15 minutes, paid orders pushed back automatically, and all three forms sent to HubSpot with UTM data.

  3. Effort

    About 60 hours, including a staging copy of the ERP connection and a week of parallel running before the switch.

  4. After launch

    Two mapping fixes in the first month, both covered by the 30-day bug fix period. Since then, the log screen is where the client’s team looks first.

Agencies that send us integration work

Mostly agencies whose clients sell B2B or run WooCommerce stores with an ERP behind them.

  • Agencies with B2B and lead generation clients
  • WooCommerce agencies syncing with an ERP
  • Marketing agencies connecting CRMs and ad platforms
  • Agencies building client portals
  • Teams without a backend developer
  • Agencies replacing fragile connector plugins

API integration FAQ

Almost any service with a documented API: CRMs, payment providers, email platforms, ERPs, booking tools and custom systems.

A reliable plugin when one fits, custom code when the logic is specific to your client’s business. Often a mix of both.

Bugs in the first 30 days after launch are on us. After that, a retainer covers monitoring and updates, so an API change doesn’t break the client site. Most providers announce breaking changes months ahead, and we plan around them.

Yes. We build custom REST API endpoints for mobile apps, headless front ends and partner systems.

In the server configuration or environment variables. Never in the theme, and never in Git.

Related services

Custom plugin development

When the integration needs its own admin screens and business logic.

Custom WordPress plugins

WooCommerce development

Stores connected to ERPs, payment providers and shipping APIs.

White label WooCommerce

Retainer packages

Monthly hours to monitor integrations and keep up with API changes.

WordPress retainers

Which systems need to talk to each other?

Tell us, and we’ll send a short spec and a quote. We reply within one business day.