Self-hosted subscription billing and PCI DSS scope

A self-hosted billing system can stay out of most PCI DSS scope if card data never reaches it. This page explains how gateway tokens, a vault and SAQ type decide the work.

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Keeping self-hosted subscription billing out of PCI DSS scope

If you run or plan to run Kill Bill or Lago, your PCI DSS scope is set by where cardholder data is stored, processed or transmitted, not by the billing brand you chose. The practical goal is a design in which the billing platform never holds a primary account number, so the cardholder data environment stays small and provable. PCI DSS v4.0.1 is the only active version of the standard, since v4.0 was retired on 31 December 2024. The PCI Security Standards Council owns the standard but does not enforce it or impose penalties. The payment brands decide which entities must validate and run any enforcement, so confirm your acquirer's and card brands' requirements before you scope the work. Validation takes the form of a Report on Compliance completed by a Qualified Security Assessor, or a Self-Assessment Questionnaire, each backed by an Attestation of Compliance (AOC). A certificate does not count as validation.

Your first decision is architectural. Billing platforms usually receive card details only through a payment page, hosted fields or an SDK that tokenizes the data before it reaches your servers. Confirm that your Kill Bill or Lago payment plugin stores only the gateway's token and card metadata, and that no request body, log line, webhook payload or database column captures a full PAN or sensitive authentication data. Mapping every component that touches card data, including the database, backups, message queues and support tooling, gives you the scope boundary to defend. Where a vault is needed for multi-processor routing, an orchestrator such as Hyperswitch is a separate decision with its own scope. Its docs describe a self-hosted, in-house PCI model in which the merchant is fully responsible for PCI DSS certification and data handling. Ask your partner to document which vault model you are using before you choose the SAQ type or ROC route, because that choice determines your assessment burden.

Treat the scope diagram and data flow as a controlled artifact. Ask your implementation partner to produce it as part of the design phase, then have your qualified assessor or acquirer confirm it. Plan for the requirements that stay in scope regardless of tokenization, such as network segmentation, access control, logging and vulnerability management. The standard's requirement set is organized into 12 principal requirements grouped under six goals. Also note that the PCI SSC opened a request for comments on v4.0.1 from 3 June to 20 July 2026, and as of October 2026 it had announced no release date for a successor, so track that announcement without assuming a new version will simplify your work.

What pulls a billing system into PCI DSS scope

A self-hosted billing platform touches cardholder data in more places than the checkout page. The components below are the ones that most often decide whether the billing environment is in scope, and each one is worth confirming with your acquirer before the architecture is fixed.

Card entry forms

Any page or iframe where a customer types a card number is the most direct point of capture. If the billing system's own portal renders the card fields and posts them to your servers, the entire portal and its hosts fall into the cardholder data environment. Hosted fields or a gateway-controlled iframe keep raw card numbers off your domain. Confirm with your acquirer exactly which script and frame origins your pages load and who controls them.

Stored PANs in the billing database

A primary account number written to a Kill Bill or Lago table, a backup, a CSV export or a log file makes that store a cardholder data environment in its own right. The usual pattern is to keep only a gateway token, a card brand and the last four digits, and let the processor or a dedicated vault hold the full number. Ask your acquirer to confirm which fields your billing schema will hold and whether any custom plugin writes additional payment data.

Webhooks and logs carrying card data

Gateway webhooks, payment plugin payloads and application logs often contain full request bodies, expanded card objects or debug output. These copies are easy to overlook because they sit outside the database. Each log sink, message queue and retry buffer that receives payment events needs a documented data flow and a filter that strips sensitive fields. Confirm which event types your gateway sends and whether they include anything beyond a token.

Administrative access to payment settings

Users who can change gateway credentials, webhook endpoints, routing rules or the card vault configuration can redirect or capture payment data even without touching a card number directly. Those accounts belong in the scope of access controls and privileged access reviews. Confirm with your acquirer how the payment administration role is defined, whether multi-factor authentication is required for it, and how changes to payment settings are logged and approved.

Interfaces to the payment gateway

The connection between the billing system and the gateway or orchestrator determines what crosses your network. A direct API call that sends raw card data from your servers is the highest-scope pattern. A token exchange where the gateway receives the card and returns a reference keeps your systems out of cardholder data flows. Confirm the integration method, the network paths and the service provider responsibility matrix in writing before development starts.

Mapping PCI DSS v4.0.1 requirements to billing functions

This table maps the 12 principal PCI DSS v4.0.1 requirements, grouped under six goals, to tasks a self-hosted billing system performs. Read each row as the question an assessor will ask of your billing environment, the evidence to prepare and where controls usually fail. The main takeaway: the fewer places that touch card numbers, the smaller the set of requirements that applies to the billing platform itself.

RequirementBilling taskEvidence an assessor expectsWhere it usually fails
1. Install and maintain network security controlsIsolate the billing app, database and admin console from the card vault and payment connectorsCurrent network diagrams, segmentation rules and reviews of allowed flowsFlat Kubernetes networks where billing pods can reach the vault namespace
3. Protect stored account dataStore gateway tokens in Kill Bill or Lago, never raw card numbers; card data stays with the gateway or vaultData discovery results, token inventory and proof that no card number appears in logs or exportsCard numbers captured in invoice notes, support tickets, CSV exports or debug logs
4. Protect cardholder data during transmissionEncrypt hosted payment page and webhook traffic between the customer browser, billing system and gatewayTLS configuration results, certificate inventory and webhook endpoint settingsInternal service calls left unencrypted, or webhook endpoints that accept unsigned requests
6. Develop and maintain secure systems and softwareControl plugin releases, catalog and price changes, and payment configuration through reviewed change ticketsChange records, approvals, separated test and production configurations and patch timelinesPrices or gateway settings edited directly in production by an admin account
7. Restrict access by business need to knowLimit who can change catalogs, issue refunds and credits, or view gateway keysRole matrix, access review records and least-privilege reportsShared admin accounts and broad roles that combine invoice edit and payout rights
8. Identify users and authenticate accessEnforce MFA on billing admin consoles and the Hyperswitch Control Center, which supports OIDC single sign-on onlyMFA enforcement settings, account lifecycle records and authentication logsControl Center has no SAML, SCIM or JIT provisioning, so confirm how removed users are deactivated
10. Log and monitor accessLog admin actions, price changes, refunds and vault calls, then forward logs to a monitored storeLog samples, retention settings, alert rules and review recordsLogs capture payment events but omit who changed a price or issued a refund
11. Test security regularlyRun internal and external scans and penetration tests on the billing app, APIs and webhooksScan reports, penetration test reports and remediation trackingTesting limited to the marketing site while the billing API and admin console go untested
12. Support security with policies and programsAssign ownership for billing security and document due diligence on gateways and hosting providersWritten policy, responsibility matrix and service provider inventoryGateway and hosting providers not inventoried or reviewed on a defined schedule

Gateway tokens, in-house vault or external vault: which model fits

In this model, Kill Bill or Lago never receives a full card number. The customer enters card details into a gateway-hosted payment page or form element, the gateway stores the card, and the billing system keeps only the token and the metadata needed to charge the customer later. Cardholder data stays in the gateway's environment, so the billing platform's role for card data is narrow: it handles payment method references, webhooks and invoices without touching PANs. Scope is usually the smallest of the four options, but that depends on how the payment page is built and on what your own systems can see.

  • Tokens only: Confirm that the Kill Bill or Lago payment plugin stores gateway payment method identifiers and does not keep raw PANs, CVVs or full track data in its database, logs or exports.
  • Hosted card capture: Card fields should load from the gateway's iframe or redirect page so your servers never handle the number.
  • Logs and webhooks: Application logs, error traces and webhook payloads are common places for accidental card data, so test them before go-live.
  • Gateway dependence: Your scope relies on the gateway's own compliance evidence. Changing gateways or building a custom card form reopens the scope question.

Ask your acquirer which questionnaire applies to your hosted page integration, and request the gateway's current Attestation of Compliance for your records.

Which open-source platforms fit a PCI-scoped billing build

A PCI-scoped billing build usually separates three jobs: recurring billing logic, payment routing and card vaulting, and the downstream ledger that receives the results. The cards below cover the platforms that play each role and what to confirm before any of them touches cardholder data.

Kill Bill as the billing engine

Kill Bill is an open source subscription billing and payments platform licensed under Apache-2.0, and killbill-0.24.22 was published on September 29, 2026. In a PCI-scoped design it should hold plans, invoices and subscription state while card numbers never reach it. Confirm which payment plugin you will use, how it receives gateway tokens, and whether any of your own plugins or logs could capture payment fields.

Lago as the usage-based alternative

Lago is a candidate for usage-based metering and invoicing in the same design. Its current version and license must be confirmed directly with the vendor before you rely on them in a scope document. The PCI question is the same as for Kill Bill: confirm that the payment provider connection is tokenized, and that event payloads and webhooks carry no card data.

Hyperswitch as the payment vault layer

Hyperswitch is an Apache-2.0 composable payments platform, and v1.128.0 was published on October 16, 2026. It ships Helm charts for Kubernetes and a separate card vault that stores card data for the platform. Choosing its self-hosted in-house PCI model makes you fully responsible for PCI DSS certification and data handling, so the vault model decision drives your SAQ or ROC path.

Hyperswitch vault deployment models

Hyperswitch documents three vault models: native in-house PCI, orchestration with an external PCI vault provider, and orchestration with the SaaS Hyperswitch Vault. Each one places the PCI boundary in a different spot. Ask your assessor which model yields the smallest cardholder data environment for your architecture, and confirm the provider's own PCI attestation if you outsource.

Hyperswitch control center access

The Control Center supports single sign-on through OpenID Connect only, with no SAML, JIT or SCIM provisioning, and roles are managed inside Hyperswitch rather than mapped from your identity provider. Access to a dashboard that can view payment data is in PCI scope, so plan invited-user onboarding, offboarding and role reviews as manual controls with their own evidence.

Apache Fineract and Odoo as downstream consumers

Apache Fineract (Apache-2.0, version 1.15.0 published July 14, 2026) and Odoo (LGPL-3.0 Community core) are relevant only when they receive billing outputs such as invoices, payments and ledger postings. Neither should store or process card numbers in this design. Confirm that the interface passes only tokens, amounts and references, and that reconciliation data is kept out of any PCI-scoped log.

How admin access to the payment stack is controlled

Does Hyperswitch Control Center support SAML single sign-on?

No. The Hyperswitch Control Center supports single sign-on through OpenID Connect only, and SAML is not supported. If your identity provider is SAML-only, you need an OpenID Connect bridge or a different admin access design before the dashboard can authenticate staff through your directory. Confirm the current SSO configuration steps in the Hyperswitch docs on configuring SSO for the Control Center and test them against your own identity provider before you commit to the design. Your identity team should also confirm how the OpenID Connect client is registered, how signing keys rotate, and what happens to sessions when a user is disabled in the directory.

Can Hyperswitch provision users automatically with JIT or SCIM?

No. The Control Center does not offer just-in-time provisioning or SCIM provisioning, so a user cannot be created automatically on first login or pushed from your directory. An administrator must invite each user first, which means joiner, mover and leaver steps have to be run as manual tasks or scripted through your own process. Offboarding deserves particular attention: removing a person in the identity provider does not, by itself, remove their Hyperswitch account, so your procedure must include disabling the invited user inside the Control Center. Record each invitation and removal as a ticket so the access history can be shown to an assessor.

How are roles managed when identity provider groups cannot map to them?

Roles are managed inside Hyperswitch, not mapped from your identity provider. Group membership in your directory does not assign permissions in the Control Center, so each role change is a deliberate action in the dashboard. Design a small, written role model before go-live, separating people who configure connectors and routing, people who view reports, and people who can reveal or manage vault and key material. Review assignments on a fixed schedule and keep the review evidence. Confirm with the vendor and in your own test environment exactly which permissions each built-in role grants, because a role that looks read-only may still expose sensitive configuration.

Does multi-factor authentication apply to Hyperswitch admin accounts?

MFA is enforced by your identity provider, not by a Control Center setting you can assume exists. When you use OpenID Connect, sign-in to the dashboard goes through your provider, so MFA policies on that provider apply to the login, and you should require them for every admin role. Confirm whether any local or break-glass accounts exist in your deployment, since accounts that bypass the identity provider would sit outside your MFA policy. Your team should test the full sign-in path, including password reset and account recovery, to make sure none of those flows skip the second factor.

What do the FTC Safeguards Rule access controls require for payment admins?

If your business is a covered financial institution under the FTC Safeguards Rule, 16 CFR 314.4 requires multi-factor authentication for any individual accessing any information system, along with logging of authorized user activity and change management procedures. Invite-only onboarding and MFA at the identity provider can support those requirements, but they do not satisfy them alone. You also need logs of admin actions that reach the billing and payment systems, a documented change process for connector and routing changes, and evidence that your access reviews happen. Whether your organization is covered is a legal question to settle with counsel before you map controls to this rule.

Who builds and operates this admin access model, and what does it cost?

Cost depends on how much identity integration, role design and evidence work the scope includes, and DeployOpen does not publish prices. Your identity provider team, your internal security and compliance staff, and any implementation partner each carry part of the work. The recurring cost is the ongoing access review, invitation and removal handling, and log retention, which continue after launch. Ask any partner for a written scope that lists the OpenID Connect configuration, the role model, the MFA verification, the runbooks for joiners and leavers, and the evidence package, along with who maintains each item after go-live.

What evidence should an assessor expect for admin access to the payment stack?

Assessors usually ask for a current list of admin users and roles, the invitation and removal records for each person, sign-in records showing the MFA method used, and periodic access review sign-offs. For a PCI DSS assessment, the evidence should match the scope your assessor agreed, so the list of people who can reach the vault, encryption service and Control Center must be complete. Your assessor decides what is sufficient, and DeployOpen prepares systems, controls and evidence for those assessments but does not issue reports or attestations. Build the evidence pack while you configure the system, not after an audit request arrives.

Is invite-only onboarding enough to control who can change payment settings?

Invite-only onboarding limits who can enter the dashboard, but it does not by itself limit what an admin can change. Pair it with role separation, so that changes to connectors, routing rules and vault settings require a role that is granted deliberately and reviewed. Add change control on top: approvals for configuration changes, a record of who made each change, and a check that production changes match an approved request. Test these controls in a non-production environment first, because the exact permissions in each role determine whether the separation holds.

Evidence auditors ask for and which component produces it

This table maps each piece of evidence an assessor typically asks for to the component or record that produces it in a self-hosted billing stack. Read it as a checklist: if a row has no owner or no retained record, the scope statement is weaker than it looks. DeployOpen prepares this evidence, but the Attestation of Compliance comes from the assessor, not from DeployOpen or the vendor.

EvidenceProduced byWhat the assessor checks
Network diagram and scope statementArchitecture team, mapped against the billing, vault and payment flowsWhich systems store, process or transmit cardholder data, and which are out of scope with a stated reason
Data flow showing PANs never reach Kill Bill or LagoGateway or orchestrator tokenization at the client, documented per payment pathCard numbers are captured by a hosted field or SDK and only tokens or references are passed to billing
Vault and encryption key management recordsHyperswitch card vault and encryption service, or an external PCI vault providerKey custody, rotation, access to key material and where card data is actually stored
Access review and invite logsIdentity provider logs plus Hyperswitch Control Center user and role recordsNamed accounts, periodic reviews and removal of users who no longer need access
Change records for price and gateway configurationVersion control or ticketing for catalog, price and gateway settings, with approvalsWho changed a price or routing rule, when, why, and who approved it
Logs of user activityApplication, database and admin access logs forwarded to a central storeRetention, tamper resistance and review of administrative and payment-related actions
Penetration test and vulnerability scan reportsIndependent testers and scanning tools covering the in-scope componentsScope covers the billing, vault and orchestrator components, with findings tracked to closure
SAQ or ROC with AOCQualified Security Assessor for a ROC, or the merchant or provider for an SAQ, using official PCI SSC templatesThe AOC is signed by the assessor or the entity, not by DeployOpen; certificates are not accepted as validation

What tooling alone does not satisfy

A vault or orchestrator reduces the card data a billing system touches, but it does not make the environment compliant. The cards below cover the gaps that stay with the merchant after the platform is selected, and each one maps to a decision the implementation team has to make and document.

PCI DSS is controls, not a product

PCI DSS is a set of requirements covering network security, access, logging, testing and policy across every system that stores, processes or transmits cardholder data or could affect that environment. No platform, including Hyperswitch, Kill Bill or Lago, makes a deployment compliant on its own. Ask each vendor which requirements their component helps you meet and which remain your responsibility.

Merchant owns the in-house vault

In the self-hosted, in-house PCI model, the Hyperswitch documentation states that the merchant is fully responsible for PCI DSS certification and data handling. Running the card vault yourself moves the cardholder data environment into your assessment scope, including key management, access and hosting. Confirm this allocation in writing before choosing the model.

Customized approach needs mature risk management

PCI DSS v4.x allows the customized approach, which meets a stated security objective by a different method than the defined approach. The option is generally reserved for entities with robust security and risk management, and it requires documented evidence of how the objective is met. A billing team without a formal risk process should expect to use the defined approach.

No next PCI DSS version announced

The PCI SSC ran a request for comments on v4.0.1 from June to July 2026, but as of October 2026 it had announced no release date for the next version. Plan against v4.0.1, which is the only active version, and build a review step into the roadmap so that a future revision does not force an unplanned rework of the billing architecture.

Vault choice does not remove segmentation

A tokenizing vault keeps card numbers out of the billing database, but the systems that call the gateway, the servers that hold API keys and the logs that record requests can still fall into scope. Network segmentation, centralized logging, access reviews and penetration testing remain required. Ask the implementation partner to draw the data flow and mark which systems can affect the cardholder data environment.

How a PCI-scoped billing rollout proceeds

The sequence fixes the payment model and cardholder data boundary first, so that the billing system, the vault and the network controls are built around a scope that an assessor or acquirer can confirm.

  1. Confirm acquirer and SAQ path

    Before any build work, the merchant confirms with its acquirer or payment processor which PCI DSS validation route applies, including the Self-Assessment Questionnaire type and whether a Report on Compliance from a Qualified Security Assessor is expected. The PCI SSC does not enforce compliance, so the payment brands and the acquirer set the requirement. Done means a written note from the acquirer naming the validation route, the SAQ or ROC, and the attestation the merchant must sign. Ask the acquirer whether it accepts a hosted payment page or iframe model and what evidence it expects for it.

  2. Define the cardholder data environment

    The engineering team, with the security lead, maps every system that stores, processes or transmits cardholder data or could affect its security. For a self-hosted Kill Bill or Lago deployment, this covers the billing application, its database and backups, logs, reporting exports, support tooling and any plugin that touches payment details. Done means a data flow diagram and an inventory showing which components hold no card data, which only see tokens, and which fall into scope. Components marked as out of scope must be justified in writing, since scope decisions drive the rest of the work.

  3. Select the vault model

    The team decides where card data is captured and stored. Options include a gateway-hosted payment page that returns only a token, a self-hosted orchestrator vault such as the Hyperswitch card vault with in-house PCI responsibility, or an orchestration model that uses an external PCI vault provider. The Hyperswitch docs state that under the self-hosted in-house model the merchant is fully responsible for PCI DSS certification and data handling, so the decision carries a large assessment burden. Done means a signed decision record that names the vault owner, the key management owner and the assessment route it implies.

  4. Build the tokenized integration

    Developers connect the billing system to the chosen payment layer so that the billing database stores only gateway or vault tokens, card brand, expiry and last four digits where the acquirer allows them. Payment method updates, dunning retries and refunds run through the tokenized interface, never through a form that passes raw card numbers to billing code. Done means test cases proving that no card number, CVV or full track data reaches application logs, database tables, message queues or exports, verified in a non-production environment with a sample of test cards.

  5. Segment networks and harden

    The engineers place the in-scope components in a segmented network zone, restrict inbound and outbound traffic to documented flows, and apply multi-factor authentication and role-based access to administrative consoles, including the Hyperswitch Control Center. Because the Control Center supports OpenID Connect single sign-on only, with no SAML, SCIM or JIT provisioning, the team records how users are invited and removed. Hardening covers configuration baselines, patch routines, encryption of stored data and logging of administrative activity. Done means segmentation test results and a hardening checklist signed by the system owner.

  6. Collect evidence

    The compliance lead assembles the artifacts an assessor will ask for: the scope inventory, data flow diagrams, vault decision record, configuration evidence, access reviews, change records, log samples, vulnerability scan results and penetration test reports. Each requirement in the chosen validation template is mapped to the evidence that supports it, and gaps are logged with owners. Done means an evidence index that a QSA or the acquirer can follow without asking the engineering team to explain the system from memory.

  7. Assess with the QSA or acquirer-accepted route

    The merchant completes the agreed assessment, either a Report on Compliance by a Qualified Security Assessor or the required Self-Assessment Questionnaire, and signs the matching Attestation of Compliance. Where a requirement is met through the customized approach or a compensating control, the assessor reviews the documented objective and risk analysis. DeployOpen prepares systems, controls and evidence for this step but does not issue reports, attestations or certifications. Done means an accepted AOC on the official PCI SSC template, shared with the acquirer, with a recurring review calendar for the next validation cycle.

Questions buyers ask before hiring help on billing PCI scope

What does PCI scope work for a self-hosted billing system cost?

The cost depends on the scope of the cardholder data environment, the vault model you choose, the number of payment and tax integrations, and the volume of evidence the assessor will need. A single gateway with hosted fields and no stored card numbers is a much smaller piece of work than a self-hosted vault that holds card data in your own environment. Costs fall into two groups. Implementation work is one-time: scoping, architecture review, network segmentation, configuration, logging and documentation. Recurring costs include the assessor's annual validation, quarterly scans where they apply, staff time for access reviews and change control, and platform upgrades. Ask any partner for a written scope that lists the systems in scope, the vault model, each integration and the evidence set before you compare quotes. DeployOpen does not publish a price list; a quote follows from that written scope.

How long does a PCI DSS scope project take?

The timeline depends on your environment, how many systems touch cardholder data, and when your assessor can review the work. A billing system that only receives gateway tokens will move faster than one that needs a self-hosted vault, network segmentation and a full review of administrative access. Two external dependencies often set the pace: the assessor's schedule and the acquirer's or payment brand's requirements for validation. Confirm the assessment type early, because a Self-Assessment Questionnaire and a Report on Compliance involve different effort. Ask your partner to put milestones, dependencies and the assessor's review window into the written scope so the timeline is tied to named work rather than estimates.

What does our team need to supply for a PCI scope engagement?

Most of the delay in these projects comes from missing access and missing decisions, not from the technical work. Plan to supply the following before work starts:

  • Named contacts at your acquirer or payment service providers who can confirm validation requirements and approve the architecture.
  • Read access to current architecture diagrams, network designs, cloud account structure, Kubernetes or hosting configuration and existing logs.
  • Named owners for each change type, including catalog and price changes, gateway configuration, key management and access approvals.
  • A decision on the vault model and on who holds responsibility for cardholder data handling.

Without these, the scoping step cannot close, and the assessor will ask for evidence that does not yet exist.

Can an internal team complete PCI DSS scoping for a self-hosted billing system alone?

An internal team can do scoping alone if it has people who understand cardholder data flows, network segmentation, key management and the assessment type your payment brands require. The gaps usually appear in three places: confirming which components are in scope, documenting the evidence an assessor will sample, and keeping that evidence current through upgrades. Many teams keep the delivery work in-house and bring in outside help for the scope review or the evidence pack. Be honest with yourselves about who will maintain the setup after go-live, since PCI DSS validation is an annual exercise tied to the systems as they run, not as they were designed. DeployOpen can plan, implement and document the environment, but the assessment itself belongs to your QSA or the applicable assessor.

Does DeployOpen issue the PCI DSS Attestation of Compliance?

No. DeployOpen does not issue Attestations of Compliance, Reports on Compliance or any other validation. Those documents come from a Qualified Security Assessor for a Report on Compliance, or from the merchant or service provider for a Self-Assessment Questionnaire, each with an Attestation of Compliance that the payment brands accept. DeployOpen prepares the systems, network controls, configuration records and evidence that the assessor or your self-assessment will rely on. Ask your acquirer which assessment type applies to your setup before you scope the work, and ask any partner to state in writing what it delivers for evidence and what remains with your assessor.

How does the PCI DSS version affect the work I need to pay for?

The active version matters because it determines the requirements your assessor will test. PCI DSS v4.0.1 is the only active version, since v4.0 was retired on 31 December 2024 and v3.2.1 was retired on 31 March 2024, according to the PCI SSC. The PCI SSC ran a request for comments on v4.0.1 from 3 June to 20 July 2026 to start the next iteration, and as of October 2026 it had announced no release date for a new version. Ask your partner how they will track changes to the standard and whether the scope includes a review if a new version is published during your engagement.

What should I ask about the vault model before I sign a scope?

The vault model sets how much of the cardholder data environment you own. In the self-hosted, in-house PCI model, the Hyperswitch documentation states the merchant is fully responsible for PCI DSS certification and data handling. In the model with an external PCI vault provider, such as VGS or Tokenex, the scope shrinks but depends on that provider's own validation. Ask whether the vault provider's attestation will be available to your assessor, how tokens are issued and who controls the keys. Get the answer in writing before you compare quotes, because the vault choice drives most of the cost difference between two proposals.

What DeployOpen scopes before work starts

Every DeployOpen engagement on a self-hosted billing stack starts with a written scope that names the systems, data flows and deliverables before any work begins. For a Kill Bill or Lago deployment with card data kept out of scope, that scope should list each component that touches payment data, the gateway or Hyperswitch vault that holds the tokens, the network zones and the people who administer each layer. Fixed scope means the boundary is agreed in writing, so a change to it (for example, adding a card form inside the billing portal) is a documented change request with its own quote and timeline, not a surprise during testing. Ask for the scope document to show the cardholder data environment boundary as a diagram and a component list, and confirm who is accountable for each row.

DeployOpen prepares the evidence package that a Qualified Security Assessor or a merchant's acquirer will ask for, but it does not issue a Report on Compliance, an Attestation of Compliance or any certification. The package typically covers the network and data-flow diagrams, configuration baselines for the billing, gateway and vault services, role and access records, logging and change-management records, and the results of testing. Under the Safeguards Rule (16 CFR 314.4), penetration testing and vulnerability assessments are expected at least every six months where continuous monitoring is not in place, so testing should be scheduled into the scope rather than added later. DeployOpen's security testing service can cover the application, API and infrastructure layers around the billing system. Confirm with your assessor which evidence they accept and in what format before the scope is signed.

Ongoing work after go-live is handled through retainers for support, upgrades and continuous testing, which are separate from the fixed-scope build. Upgrades matter here because PCI DSS v4.0.1 is the only active version, and the PCI SSC has announced no release date for a successor, so the controls mapped in the scope may need review when the standard changes. Ask each partner how an upgrade of Kill Bill, Lago, Hyperswitch or the card vault would be tested against the PCI scope, who signs off the change and how the evidence is refreshed for the next assessment cycle. Agree the retainer's response expectations in writing, since DeployOpen does not publish a price list and quotes follow from the scope.

How DeployOpen delivers PCI-scoped billing and its evidence

DeployOpen plans, implements, hardens, documents and supports self-hosted billing platforms inside your own cloud accounts, data centers or air-gapped networks. For PCI DSS scope, we start by agreeing in writing which systems touch cardholder data, then build the card path around gateway or vault tokens and prepare the evidence your assessor will request.

How we scope

  • Map every system that stores, processes or transmits cardholder data, including billing, vault and logging components.
  • Confirm with your acquirer or payment brand which SAQ type or ROC route applies to your setup.
  • Agree the scope, deliverables and timeline in a written fixed-scope document before work starts.

How we build

  • Configure the billing platform to hold only gateway or vault tokens, with no PANs in databases, logs or exports.
  • Deploy the vault and orchestration layer in your environment with network segmentation around the card data environment.
  • Run security testing of the integrated payment path, with findings tracked to closure in a documented register.

How we hand over

  • Document the cardholder data flow, component inventory and shared responsibility split between you and each provider.
  • Prepare control evidence such as configuration baselines, access reviews and change records for your QSA or internal assessor.
  • Transfer runbooks, admin access and operating procedures so your team can run the platform after handover.

How we support

  • Offer ongoing support, upgrades and continuous testing as a retainer after handover.
  • Track upstream releases and PCI DSS version changes, then assess their effect on your scope and controls.
  • Confirm with your assessor and payment brands any scope change before you alter the card data path.

Talk to our team.

Tell us what you're working on, whether it's a deployment, an audit, a security test or a cyber range. You'll speak with an engineer who can help you scope it.

  • 30-minute call: free, with no obligation.
  • NDA on request: we can sign before you share details.
  • Clear next steps: a scope and plan after the call.