Building Your Own Registrar Platform

Most of our guides answer a single question — how to connect, how to register a domain, how to run a transfer. This one is different. It steps back and shows how those pieces fit together into a complete commercial platform: a storefront where your own customers search, buy, renew and manage domains under your brand, with your pricing and your billing on top of CentralNic Reseller.

The important idea running through this page is a dividing line. For every stage of the journey, some of the work is done for you by CentralNic Reseller — the registry connections, the provisioning commands, the automated renewal engine, the prepay accounting — and some of it is yours to build, because it is where your product and your business rules live: your cart, your price list, your customer accounts, your notifications. Knowing which side of that line each responsibility sits on is what turns a pile of API calls into a coherent platform.

This is a reference, not a tutorial. Rather than repeat the detail of the individual how-tos, it ties them together and links out to each one at the point it becomes relevant.

By the End of This Page You Will Have

• A mental model of the full platform, stage by stage, from account setup to customer notifications
• A clear view, at each stage, of what CentralNic Reseller provides versus what you must build yourself
• The specific guide to open for the implementation detail of every stage
• An understanding of how the CentralNic Reseller prepay model sits underneath your own end-customer billing

First Things First

This blueprint assumes you already have a funded, secured account and have chosen how you will connect. If you have not done that yet, work through Your First Day as a CentralNic Reseller and Which Integration Method Should I Choose? first — everything below builds on top of them.

The Platform at a Glance

A domain platform is a pipeline. A visitor arrives, searches for a name, adds it to a cart, pays, and becomes the owner of a registered domain that you then renew, transfer, point at DNS and bill for over its lifetime. CentralNic Reseller powers the registry-facing half of that pipeline; you own the customer-facing half.

The table below is the map for the rest of this page. Read it top to bottom as the flow a customer moves through, and use the two right-hand columns to see where responsibility sits at each stage.

Platform stage	CentralNic Reseller provides	You build
Account setup	Reseller account, users, permissions, OT&E sandbox, security	Your own end-customer accounts and sign-up
Contact management	Contact/handle objects, reusable across domains	Collecting and validating customer contact data
Domain search	Availability checks across all supported TLDs	Search UX, suggestions, result caching
Cart	Nothing — there is no server-side cart	The entire cart and checkout experience
Registration	Domain provisioning at the registry	Order orchestration, retries, confirmation
Renewal	Automated renewal engine and renewal modes	Renewal reminders, upsells, your renewal pricing
Transfers	Standard transfer-in / transfer-out operations	Auth-code collection, eligibility UX, progress tracking
DNS management	Hosted DNS (KeyDNS) and nameserver objects	DNS editor UI, templates, defaults per customer
Billing	Prepay balance charged in real time; wholesale prices	Your price list, margins, invoices, payment capture
Customer notifications	Event / poll queue for asynchronous registry events	Emails, dashboards and alerts to your customers

The rest of this page walks each row.

Account Setup

Your CentralNic Reseller account is the single wholesale relationship behind your whole platform. Every domain your customers register is registered by you, against your balance. Your customers never see or touch CentralNic Reseller — they see your brand.

CentralNic Reseller provides the reseller account itself, a full user and permission model so your systems and staff hold only the access they need, a complete OT&E sandbox to build against without spending money, and the security controls (two-factor authentication and IP allowlisting) that protect an account able to spend real funds. If you resell under your own brand, subreseller settings let you set defaults and pricing for accounts beneath you.

You build the concept of an end customer. CentralNic Reseller has no notion of your individual buyers — it sees one reseller. Your platform owns customer sign-up, login, profiles and the mapping between each of your customers and the domains you hold on their behalf.

Design Your Account-to-customer Mapping Early

Because every domain lives under one reseller account, your database — not CentralNic Reseller — is the system of record for which of your customers owns what. Get that ownership model right before you write your first order, and keep it authoritative.

Full setup walkthrough: Your First Day as a CentralNic Reseller and Authentication, Credentials & IP Allowlisting.

Contact Management

Every domain registration references contacts — the registrant, admin, tech and billing roles — and different TLDs require different combinations and data.

CentralNic Reseller provides contacts as reusable first-class objects. You create a contact once with AddContact (or Contact:Create over EPP) and receive a handle — typically a P- handle for a validated person — which you then reference from any domain that needs it. Handles can be reused across many domains and kept current with a single update.

You build the collection and validation of your customers’ contact details in your own checkout, and the logic that decides which handle to use for which role on which order. A common pattern is to create one handle per end customer and reuse it across all their domains.

Contact Data Has Real Registry Consequences

Getting contact data wrong is not a cosmetic problem. For a private person the organisation field must be left empty — placeholder text like “private” can be published in WHOIS or even cause a registry to suspend the domain for invalid data. Validate before you submit.

The handle model, the four roles, role-contact pitfalls and GDPR are covered in Understanding Contacts, Handles & Ownership.

Domain Search

Search is the front door of your storefront, and the point where availability is confirmed before anyone spends money.

CentralNic Reseller provides availability checking across every supported TLD via CheckDomain (one name) and CheckDomains (several at once), or Domain:Check over EPP. This is the authoritative answer to “can this be registered right now?”.

You build everything around it: the search box, name suggestions and alternate-TLD prompts, how you present prices alongside availability, and any caching or rate management so a busy search page does not translate into a flood of checks. Always check availability before attempting a registration — it is the cheapest way to avoid a failed order.

See the API Command Reference for the check commands and the complete domain lifecycle for how search leads into registration.

Cart and Checkout

This stage is worth calling out precisely because there is nothing here on the CentralNic Reseller side. There is no server-side shopping cart, no held reservation, no multi-item order object waiting for you to consume.

You build the cart and checkout in full: line items, quantities and registration periods, add-ons such as privacy or DNS, the running total in your own currency, and the checkout flow that captures payment and confirms intent. The cart is pure application state in your platform until the moment you commit an order.

Availability Is Not a Reservation

A domain confirmed available at the moment it is added to a cart can be taken by someone else before checkout completes — a name is only secured when the registration succeeds. Re-check availability at checkout, handle the “no longer available” case gracefully, and treat registration itself as the point of truth.

Registration

Checkout ends with the one irreversible, billable action in the whole flow: registering the domain.

CentralNic Reseller provides provisioning at the registry through AddDomain (or Domain:Create over EPP). A registration carries the period, the nameservers and the contact handles for the roles the TLD requires; many TLDs need extra data supplied through registry-specific extensions. On success the domain is live under your account and your balance is charged in real time.

You build the order orchestration: turning a paid cart into one registration call per domain, handling partial failures across a multi-domain order, retrying sensibly, recording the result against the owning customer in your database, and showing a clear confirmation. Because registration spends real money, this is the code that most deserves careful error handling and idempotency.

The end-to-end registration flow, including nameservers and TLD-specific data, lives in The Complete Domain Lifecycle; registrars building over EPP should follow the EPP Integration Guide.

Renewal

Renewal is where CentralNic Reseller does the most work on your behalf — and where the prepay model matters most.

CentralNic Reseller provides a full automated renewal engine. Domains are automatically renewed, left to expire, or deleted at the end of their lifecycle according to their renewal mode — AutoRenew (the safe default), AutoExpire, AutoDelete, RenewOnce and several TLD-specific variants. Renewal is driven by an internal renewal date (not the raw registry expiration date), and modes can be set for the whole account or per domain.

You build the customer-facing side of renewal: reminder emails ahead of the renewal date, self-service auto-renew toggles that map to the CentralNic Reseller renewal mode, upsell and multi-year offers, and your own renewal pricing. You also decide your operating posture — lean on automated AutoRenew, or handle renewals explicitly yourself.

Automated Renewals Depend on a Funded Balance

If your account cannot cover a renewal fee in full at the moment of renewal, the domain is left to auto-expire and removed — recovering it then requires a paid restore. Keep your balance ahead of your renewal volume and use low-balance warnings. This is the single most important operational discipline for a platform at scale.

The modes, the renewal-date model, grace periods and restores are documented in The CentralNic Reseller Renewal System, with the customer-flow view in The Complete Domain Lifecycle.

Transfers

Bringing domains in (and letting them out) is a standard part of any platform, and an important acquisition channel.

CentralNic Reseller provides the full transfer command set — request, query, approve, reject and cancel — via TransferDomain (or the Transfer:* commands over EPP). Transfers are asynchronous: your request starts the process and the outcome arrives later, typically through the event/poll queue.

You build the customer experience around it: collecting the authorisation (“auth”/EPP) code, guiding the customer through unlocking the domain at their old registrar, checking eligibility up front, and showing live progress while the transfer completes in the background. Note that not all TLDs support changing contact handles during a transfer — plan your UX for the TLDs you actually sell.

Transfers Are Asynchronous — Design for the Wait

Unlike a registration that resolves in one call, a transfer can take hours or days and can be declined. Build a status view your customer can return to, and consume the event queue so you learn the result the moment it lands rather than polling a customer’s patience.

The eligibility rules, auth codes and failure handling are in Transfer a Domain into CentralNic Reseller, with contact-handle-on-transfer behaviour covered there too.

DNS Management

Once a customer owns a domain, they will want it to do something — and DNS is usually the first thing they ask for.

CentralNic Reseller provides two things: nameserver (host) objects you manage with commands such as AddNameserver and ModifyNameserver, and KeyDNS, our hosted DNS service for managing zone files and records (including DNSSEC and CAA), which can itself be provided to and invoiced to subresellers.

You build the DNS-editing experience your customers use: a record editor, sane defaults and templates applied at registration (so a new domain resolves the way you expect out of the box), and any bulk or per-customer nameserver policies. You decide whether customers use your KeyDNS-backed zones, point at their own nameservers, or both.

Automating records, zones and nameservers is covered in DNS Automation.

The Billing Model: Your Billing on Top of Prepay

This is the stage most often misunderstood, so it is worth being precise. There are two billing layers, and they are separate.

CentralNic Reseller provides the wholesale layer: a prepayment account. Your account carries a balance, and every registration, renewal, transfer and restore is charged against it in real time at your wholesale price — there are no invoices to wait on and no credit delays. Your wholesale rates come from your pricescale, visible under Services & Prices and per-TLD Domain prices.

You build the retail layer — the entire commercial relationship with your customers. That means your own price list and margins, your currencies, taxes, invoices, payment capture, refunds and dunning. CentralNic Reseller never bills your customers; it bills you, and your platform bills them. Your margin is the difference between your wholesale cost and what you charge.

Your Retail Revenue Must Keep the Prepay Balance Funded

Because the wholesale layer is prepaid and automated, an empty balance stops new registrations and can cause automated renewals to fail. Treat topping up the CentralNic Reseller balance as a first-class part of your finance operations, not an afterthought — set a low-balance warning and, ideally, automate replenishment ahead of demand.

The prepay model and low-balance notifications are described in Payment Settings, and the funding walkthrough is in Your First Day.

Customer Notifications

A platform that only ever pushes commands to CentralNic Reseller is half-built. Much of what matters — transfer outcomes, renewal results, restore completions — happens asynchronously, and your customers expect to hear about it.

CentralNic Reseller provides an event / poll queue: a per-account stream of asynchronous notifications for registration, renewal, update, transfer, deletion and restore events. Over EPP you read it with Poll:Request and acknowledge with Poll:Ack; over the API the same events are available through the event commands. This is how your platform learns about things that do not resolve inside a single request/response.

You build everything your customer actually sees: turning a queue message into a customer-friendly email, dashboard update or alert; expiry and renewal reminders driven by your own schedule; and the notification preferences your customers set. The queue is your source of truth for “what just happened”; the messaging is yours.

Consume the Queue on a Schedule, and Always Acknowledge

Poll regularly so events are handled promptly, and always acknowledge a message once you have safely processed it — an unacknowledged message stays at the head of the queue and blocks the ones behind it. A reliable queue consumer is the backbone of trustworthy customer notifications.

The poll queue and event message types are detailed in the EPP Integration Guide and the API Command Reference.

Putting It Together

Read as a whole, the pattern is consistent: CentralNic Reseller owns the registry-facing, wholesale, automated half — provisioning, renewal, transfers, DNS, prepay accounting and the event stream — and you own the customer-facing, retail, experiential half — accounts, search UX, cart, pricing, billing and notifications. Build cleanly to that dividing line and each half stays simple.

When you are ready to turn this blueprint into a concrete design, the next two guides help you choose a shape and, if you are coming from elsewhere, bring your portfolio across:

Reference Architectures for Domain ResellersConcrete patterns for hosting, registrar, SaaS, marketplace and corporate platforms.

Migrating from Another ProviderExport, transfer strategy, cutover timeline and risk mitigation for moving a portfolio in.

The Complete Domain LifecycleSearch, register, renew, transfer and delete — the core flows every platform automates.

Which Integration Method Should I Choose?Control Panel, WHMCS, SDK, API or EPP — pick the foundation for your platform.

EPP Integration GuideSessions, provisioning, transfers and the poll queue for registrars building over EPP.

API Command ReferenceThe authoritative list of account, domain, contact, DNS and event commands.