May 19, 2022

How Vanta's engineering team improved productivity with esbuild

As of early 2022, Vanta’s backend consists of Typescript services and lambdas, and our frontend is a React and Typescript-based single-page application. We host all this code in a monorepo. Over time, we experienced build slowdowns due to our organically growing codebase.

Ultimately, we decided to use esbuild to ensure developer edit/refresh cycles stay smooth. In this article, we’ll explore why we made this decision, how we implemented esbuild, and the results that followed.

The challenge

Our codebase has always been structured as a tree of packages. The leaf directories are services that include a common directory and are bundled up by a Dockerfile. For development, we have a docker compose setup that spins up all services, and essentially runs tsc --watch for each service.

Back in the early days, we leveraged symlinks to manage the dependency tree, which we replaced with Typescript Project References to simplify our setup and accelerate builds.

We experienced reasonable performance with this setup for a few years until tsc --watch incremental builds were slowing down. It was taking tens of seconds to re-compile our backend for even the most minimal changes. Our first recourse was to understand the problem using Typescript’s great performance debugging guide. We discovered a few type-heavy packages, like our very own ts-json-validator, and certain usage patterns of mongoose were leading to severe slowdowns. Through a series of casts and manually provided types, we relieved some burden from Typescript's automatic inference and managed to cut build times by >50%. Even then, with a growing engineering team and codebase, we knew that this wouldn’t be a long-term solution, and re-compilation times steadily crept back up.

After another round of Typescript profiling, we noticed an interesting comment on HackerNews that talked about replacing the Typescript compiler with esbuild. After a quick manual prototype, we found that esbuild could re-compile one of our smaller services in under a second, so we decided to investigate whether we could replace all our transpilation with esbuild.

What is esbuild?

esbuild is a fast Javascript bundler written in Go that focuses on correctness and performance. Bundlers traditionally take existing source code and “bundle” it up into a smaller output file so that it can be served faster over the internet, but over the years, bundlers have taken on additional responsibilities, like transpiling from Typescript to Javascript. All we really needed for backend code was that transpilation step, along with a few niceties like source maps for better stack traces in our observability tools.

The strategy


Our biggest roadblock to enabling esbuild globally in our codebase was that we didn’t have the Typescript option esModuleInterop enabled.

Understanding the module ecosystem

Modern programming languages have a module system so developers can separate code with reasonable boundaries into a self-contained package or module and import that code somewhere else. Javascript, famously written in ten days, did not start off with a module system. Over time, one working group came up with commonjs for modules in Node. Sometime after, the community came up with a different module system—ES Modules, or ESM, with dedicated Javascript syntax for imports. The Javascript community is standardizing ES Modules since they’re the in-built system, and have slightly better and stricter semantics. Here’s a good blog on the intricacies and nuances of the two systems.

Difference in syntax

How Typescript fits in

Typescript added import statements before Javascript natively supported import. And Typescript transpiled import * as statements into CommonJS require statements:

This breaks compatibility with the new ESM spec, as CommonJS require has looser semantics than ES6 import * as. For example, require is allowed to return a non-object, whereas import * as is required to return a plain object. This behavior goes against one of their stated design goals to align with ECMAScript proposals.

Since Typescript’s generated code didn’t conform to the spec, they released an option for interoperability called esModuleInterop. They’ve enabled it by default for new projects, and highly recommend that it’s enabled for all projects going forward.  esbuild does not need to break the spec, so its generated code has different semantics than Typescript generated code with esModuleInterop: false. For example, esbuild generates code that assumes imported modules are not callable and are read-only. This is such a common issue that there’s documentation about it, and the recommended path forward is to enable esModuleInterop for codebases to use esbuild.

We needed to take on two kinds of tasks to correctly enable this option: re-do our imports and clean up mocking code.

Re-doing imports

esModuleInterop automatically enables allowSyntheticDefaultImports, so we migrated many of our imports. This wasn’t strictly required, but it was the cleaner end state with this option enabled.



Unfortunately, this led to a few breakages that weren’t caught at compile-time, since this only retained the same behavior for packages that didn’t have pre-existing default exports. We discovered most bugs here through testing and deployment in our staging environment.

Re-doing mocks

We use sinon for our mocks in tests. An example:

This would no-longer work with esModuleInterop because ES modules are not directly assignable. We were essentially modifying code that was imported, which is a code-smell. We decided to remove mocks where it was easy, and export objects that sinon could mutate when it wasn’t, rather than trying to redo the import itself. This was another common issue with a lot of discussion in the community.

The changes here were pretty mechanical as soon as we got a handle on the problem, and it took one PR for each of the handful of modules affected.

These migrations were the bulk of the work required before we could use esbuild. 

Build script

With our migration to esModuleInterop complete, we wrote a bash script that essentially set up nodemon to watch our Typescript files, and re-ran esbuild on changes.

A large issue worth noting here is that esbuild is explicitly not a Typescript compiler replacement, so it doesn’t grok project references. Fortunately, since it’s so fast, we rebuild all running services in parallel when there are any code changes to our common directories, and that’s worked out fine in practice. Another issue is that esbuild doesn’t recognize JSON entry-points, so it doesn’t copy over JSON files into the output directory which can be imported with resolveJsonModule: true in Typescript. So we just copy those over manually through a find and cp.

The rollout

First, since esbuild is not a Typescript compiler, we made it clear to developers that their code might rebuild successfully through esbuild, even if compilation really should have failed due to type errors. Instead, they could use editors to find most compilation errors and run the Typescript compiler on watch mode manually while doing large refactors to catch compilation errors. We also run the Typescript compiler in CI to make sure that no compilation errors get through. Developers seemed to prefer this trade-off.

Second, our team strongly believes that our systems are as consistent as possible in development and production. Therefore, if developers were interacting with esbuild-built code locally, we should ship esbuild-built code to production. To roll this out, we first enabled esbuild for local development behind an opt-in flag. Next, we pushed esbuild-built code to our staging environment, and finally to production. After almost a year in production, we haven’t noticed any issues with the exception of missing source maps which we fixed by tweaking a few flags.

The results

Overall, we’ve been satisfied with our esbuild experience. Looking back, we should have looked into swc a little more, especially since we used Parcel for our front-end code and Parcel 2 uses swc behind the scenes. But it seems easy to switch from one to the other since the bulk of the work was not strictly related to esbuild.

Most developers aren’t aware that we use esbuild behind the scenes, and we count that as a success. On the other hand, we’ve run into more issues around the Typescript server in code editors, mainly around OOMs due to pathological third-party dependencies and organic codebase and dependency growth, so we’ll continue investing on that front.

Credits go to Evan Wallace, the author behind esbuild, for helping push the Javascript ecosystem towards better, faster tooling. If you’re interested in solving tricky problems to make the internet a more secure place, we’re hiring! Check out our open roles here

Learn more about engineering at Vanta 

How Vanta supports a distributed engineering team
3 GraphQL pitfalls and steps to avoid them
9 security tips for startups (and how coding plays a part)


Determine whether the GDPR applies to you and if so, if you are a processor or controller (or both)

Do you sell goods or service in the EU or UK?

Do you sell goods or services to EU businesses, consumers, or both?

Do you have employees in the EU or UK?

Do persons from the EU or UK visit your website?

Do you monitor the behavior of persons within the EU?

If any of the above apply to your business, you’ll need to get GDPR compliant.

Create a Data Map by taking the following actions

Identify and document every system (i.e. database, application, or vendor) which stores or processes EU or UK based personally identifiable information (PII)

Document the retention periods for PII in each system

Determine whether you collect, store, or process “special categories” of data

racial or ethnic origins
genetic data
political opinions
biometric data that can uniquely identifying someone
religious or philosophical beliefs
health, sex life or sexual orientation data
trade union membership

Determine whether your Data Map meets the requirements for Records of Processing Activities (Art. 30)

the name and contact details of the controller
the purpose behind the processing of data
a description of the categories of data that will be processed
who will receive the data including data
documentation of suitable safeguards for data transfers to a third country or an international organization
the retention period of the different categories of data
a general description of the technical and organizational security measures

Determine whether your Data Map includes the following information about processing activities carried out by vendors on your behalf

the name and contact details of the processor or processors and of each controller on behalf of which the processor is acting, and, where applicable, of the controller’s or the processor’s representative, and the data protection officer
the categories of processing carried out on behalf of each controller
documentation of suitable safeguards for data transfers to a third country or an international organization
a general description of the technical and organizational security measures

Determine your grounds for processing data

For each category of data and system/application have you determined the lawful basis for processing based on one of the following conditions?

consent of the data subject
contract with the data subject
necessary for compliance with a legal obligation
necessary in order to protect the vital interests of the data subject or a third party
necessary for the performance of a task in the public interest or in the exercise of official authority vested in the controller
necessary for the purposes of the legitimate interests pursued by the controller or by a third party, except where such interests are overridden by the rights of data subject

Take inventory of current customer and vendor contracts to confirm new GDPR-required flow-down provisions are included

Review all customer contracts to determine that they have appropriate contract language (i.e. Data Protection Addendums with Standard Contractual Clauses)

Review all in-scope vendor contracts to determine that they have appropriate contract language (i.e. Data Protection Addendums with Standard Contractual Clauses)

Do your agreements cover the following items?
vendor shall process the personal data only on documented instructions (including when making an international transfer of personal data) unless it is required to do otherwise by EU or member state law
vendor ensures that persons authorized to process the personal data are subject to confidentiality undertakings or professional or statutory obligations of confidentiality.
vendor have adequate information security in place, technical and organizational measures to be met to support data subject requests or breaches
vendor shall not appoint or disclose any personal data to any sub-processor unless required or authorized
vendor shall delete or return all the personal data after the end of the provision of services relating to processing, and deletes existing copies unless Union or Member State law requires storage of the personal data;
vendor makes available all information necessary to demonstrate compliance and allow for and contribute to audits, including inspections

Have you performed a risk assessment on vendors who are processing your PII?


Determine if you need to do a Data Protection Impact Assessment

Is your data processing taking into account the nature, scope, context, and purposes of the processing, likely to result in a high risk to the rights and freedoms of natural persons?

Does your processing involve any of the following?
automated processing, including profiling, and on which decisions are based that produce legal effects
special categories of data or data related to criminal convictions and offenses
monitor publicly accessible area on a large scale.
If any of the above are true, you may need to conduct a Data Protection Impact Assessment for existing and new data projects.

Review product and service design (including your website or app) to ensure privacy notice links, marketing consents, and other requirements are integrated

Do you have a public-facing Privacy Policy which covers the use of all your products,  services and websites?

Does the notice to the data subject include the following items?

the identity and the contact details of the organization and its representative
the contact details of the data protection officer, if applicable
the purposes to process personal data and its legal basis for the processing
the recipients or categories of recipients of the personal data, if any
the details regarding any transfer of personal data to a third country and the safeguards taken applicable

Does the notice also include the following items?

the retention period, or if that is not possible, the criteria used to determine that period
the existence of the data subject rights (i.e. requests for information, modification or deletion of PII)
the right to withdraw consent at any time
the right to lodge a complaint with a supervisory authority
whether the provision of personal data is a statutory or contractual requirement, or a requirement necessary to enter into a contract, as well as whether the data subject is obliged to provide the personal data and of the possible consequences of failure to provide such data
the existence of automated decision-making, including profiling, and meaningful information about the logic involved, as well as the significance and the consequences

Do you have a mechanism for persons to change or withdraw consent?


Update internal privacy policies to comply with notification obligations

Update internal privacy notices for EU employees

Do you have an Employee Privacy Policy governing the collection and use of EU and UK employee data?

Determine if you need to appoint a Data Protection Officer, and appoint one if needed

Have you determined whether or not you must designate a Data Protection Officer (DPO) based on one of the following conditions (Art. 37)?

the data processing is carried out by a public authority
the core activities of the controller or processor require regular and systematic monitoring of data subjects on a large scale

If you export data from the EU, consider if you need a compliance mechanism to cover the data transfer, such as model clauses

If you transfer, store, or process data outside the EU or UK, have you identified your legal basis for the data transfer (note: most likely covered by the Standard Contractual Clauses)

Have you performed and documented a Transfer Impact Assessment (TIA)?


Confirm you are complying with other data subject rights (i.e. aside from notification)

Do you have a defined process for timely response to Data Subject Access Requests (DSAR) (i.e. requests for information, modification or deletion of PII)?

Are you able to provide the subject information in a concise, transparent, intelligible and easily accessible form, using clear and plain language?

Do you have a process for correcting or deleting data when requested?

Do you have an internal policy regarding a Compelled Disclosure from Law Enforcement?


Determine if you need to appoint an EU-based representative, and appoint one if needed

Have you appointed an EU Representative or determined that an EU Representative is not needed based on one of the following conditions?

data processing is occasional
data processing is not on a large scale
data processing doesn’t include special categories or data related to criminal convictions and offenses
doesn’t risk to the rights and freedoms of data subjects
a public authority or body

If operating in more than one EU state, identify a lead Data Protection Authority (DPA)

Do you operate in more than one EU state?

If so, have you designated the Supervisory Authority of the main establishment to act as your Lead Supervisory Authority?


Implement Employee Trainings to Demonstrate Compliance with GDPR Principles and Data Subject Rights

Have you provided appropriate Security Awareness and Privacy training to your staff?


Update internal procedures and policies to ensure you can comply with data breach response requirements

Have you created and implemented an Incident Response Plan which included procedures for reporting a breach to EU and UK Data Subjects as well as appropriate Data Authorities?

Do breach reporting policies comply with all prescribed timelines and include all recipients i.e. authorities, controllers, and data subjects?


Implement appropriate technical and organizational measures to ensure a level of security appropriate to the risk

This includes pseudonymization/ encryption, maintaining confidentiality, restoration of access following physical/technical incidents and regular testing of measures

Have you implemented encryption of PII at rest and in transit?

Have you implemented pseudonymization?

Have you implemented appropriate physical security controls?

Have you implemented information security policies and procedures?

Can you access EU or UK PII data in the clear?

Do your technical and organizational measure ensure that, by default, only personal data which are necessary for each specific purpose of the processing are processed?


Consider streamlining GDPR compliance with automation

Transform manual data collection and observation processes into continuous monitoring

Download this checklist for easy reference

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Develop a roadmap for successful implementation of an ISMS and ISO 27001 certification

Implement Plan, Do, Check, Act (PDCA) process to recognize challenges and identify gaps for remediation

Consider ISO 27001 certification costs relative to org size and number of employees

Clearly define scope of work to plan certification time to completion

Select an ISO 27001 auditor


Set the scope of your organization’s ISMS

Decide which business areas are covered by the ISMS and which are out of scope

Consider additional security controls for business processes that are required to pass ISMS-protected information across the trust boundary

Inform stakeholders regarding scope of the ISMS


Establish an ISMS governing body

Build a governance team with management oversight

Incorporate key members of top management, e.g. senior leadership and executive management with responsibility for strategy and resource allocation


Conduct an inventory of information assets

Consider all assets where information is stored, processed, and accessible

  • Record information assets: data and people
  • Record physical assets: laptops, servers, and physical building locations
  • Record intangible assets: intellectual property, brand, and reputation

Assign to each asset a classification and owner responsible for ensuring the asset is appropriately inventoried, classified, protected, and handled


Execute a risk assessment

Establish and document a risk-management framework to ensure consistency

Identify scenarios in which information, systems, or services could be compromised

Determine likelihood or frequency with which these scenarios could occur

Evaluate potential impact of each scenario on confidentiality, integrity, or availability of information, systems, and services

Rank risk scenarios based on overall risk to the organization’s objectives


Develop a risk register

Record and manage your organization’s risks

Summarize each identified risk

Indicate the impact and likelihood of each risk


Document a risk treatment plan

Design a response for each risk (Risk Treatment)

Assign an accountable owner to each identified risk

Assign risk mitigation activity owners

Establish target dates for completion of risk treatment activities


Complete the Statement of Applicability worksheet

Review 114 controls of Annex A of ISO 27001 standard

Select controls to address identified risks

Complete the Statement of Applicability listing all Annex A controls, justifying inclusion or exclusion of each control in the ISMS implementation


Continuously assess and manage risk

Build a framework for establishing, implementing, maintaining, and continually improving the ISMS

Include information or references to supporting documentation regarding:

  • Information Security Objectives
  • Leadership and Commitment
  • Roles, Responsibilities, and Authorities
  • Approach to Assessing and Treating Risk
  • Control of Documented Information
  • Communication
  • Internal Audit
  • Management Review
  • Corrective Action and Continual Improvement
  • Policy Violations

Assemble required documents and records

Review ISO 27001 Required Documents and Records list

Customize policy templates with organization-specific policies, process, and language


Establish employee training and awareness programs

Conduct regular trainings to ensure awareness of new policies and procedures

Define expectations for personnel regarding their role in ISMS maintenance

Train personnel on common threats facing your organization and how to respond

Establish disciplinary or sanctions policies or processes for personnel found out of compliance with information security requirements


Perform an internal audit

Allocate internal resources with necessary competencies who are independent of ISMS development and maintenance, or engage an independent third party 

Verify conformance with requirements from Annex A deemed applicable in your ISMS's Statement of Applicability

Share internal audit results, including nonconformities, with the ISMS governing body and senior management

Address identified issues before proceeding with the external audit


Undergo external audit of ISMS to obtain ISO 27001 certification

Engage an independent ISO 27001 auditor

Conduct Stage 1 Audit consisting of an extensive documentation review; obtain feedback regarding readiness to move to Stage 2 Audit

Conduct Stage 2 Audit consisting of tests performed on the ISMS to ensure proper design, implementation, and ongoing functionality; evaluate fairness, suitability, and effective implementation and operation of controls


Address any nonconformities

Ensure that all requirements of the ISO 27001 standard are being addressed

Ensure org is following processes that it has specified and documented

Ensure org is upholding contractual requirements with third parties

Address specific nonconformities identified by the ISO 27001 auditor

Receive auditor’s formal validation following resolution of nonconformities


Conduct regular management reviews

Plan reviews at least once per year; consider a quarterly review cycle 

Ensure the ISMS and its objectives continue to remain appropriate and effective

Ensure that senior management remains informed

Ensure adjustments to address risks or deficiencies can be promptly implemented


Calendar ISO 27001 audit schedule and surveillance audit schedules

Perform a full ISO 27001 audit once every three years

Prepare to perform surveillance audits in the second and third years of the Certification Cycle


Consider streamlining ISO 27001 certification with automation

Transform manual data collection and observation processes into automated and continuous system monitoring

Identify and close any gaps in ISMS implementation in a timely manner


Learn more about achieving ISO 27001 certification with Vanta

Book an ISO 27001 demo with Vanta

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Determine which annual audits and assessments are required for your company

Perform a readiness assessment and evaluate your security against HIPAA requirements

Review the U.S. Dept of Health and Human Services Office for Civil Rights Audit Protocol


Conduct required HIPAA compliance audits and assessments

Perform and document ongoing technical and non-technical evaluations, internally or in partnership with a third-party security and compliance team like Vanta


Document your plans and put them into action

Document every step of building, implementing, and assessing your compliance program

Vanta’s automated compliance reporting can streamline planning and documentation


Appoint a security and compliance point person in your company

Designate an employee as your HIPAA Compliance Officer


Schedule annual HIPAA training for all employees

Distribute HIPAA policies and procedures and ensure staff read and attest to their review


Document employee trainings and other compliance activities

Thoroughly document employee training processes, activities, and attestations


Establish and communicate clear breach report processes
to all employees

Ensure that staff understand what constitutes a HIPAA breach, and how to report a breach

Implement systems to track security incidents, and to document and report all breaches


Institute an annual review process

Annually assess compliance activities against theHIPAA Rules and updates to HIPAA


Continuously assess and manage risk

Build a year-round risk management program and integrate continuous monitoring

Understand the ins and outs of HIPAA compliance— and the costs of noncompliance

Download this checklist for easy reference

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Access Review Stage Content / Functionality
Across all stages
  • Easily create and save a new access review at a point in time
  • View detailed audit evidence of historical access reviews
Setup access review procedures
  • Define a global access review procedure that stakeholders can follow, ensuring consistency and mitigation of human error in reviews
  • Set your access review frequency (monthly, quarterly, etc.) and working period/deadlines
Consolidate account access data from systems
  • Integrate systems using dozens of pre-built integrations, or “connectors”. System account and HRIS data is pulled into Vanta.
  • Upcoming integrations include Zoom and Intercom (account access), and Personio (HRIS)
  • Upload access files from non-integrated systems
  • View and select systems in-scope for the review
Review, approve, and deny user access
  • Select the appropriate systems reviewer and due date
  • Get automatic notifications and reminders to systems reviewer of deadlines
  • Automatic flagging of “risky” employee accounts that have been terminated or switched departments
  • Intuitive interface to see all accounts with access, account accept/deny buttons, and notes section
  • Track progress of individual systems access reviews and see accounts that need to be removed or have access modified
  • Bulk sort, filter, and alter accounts based on account roles and employee title
Assign remediation tasks to system owners
  • Built-in remediation workflow for reviewers to request access changes and for admin to view and manage requests
  • Optional task tracker integration to create tickets for any access changes and provide visibility to the status of tickets and remediation
Verify changes to access
  • Focused view of accounts flagged for access changes for easy tracking and management
  • Automated evidence of remediation completion displayed for integrated systems
  • Manual evidence of remediation can be uploaded for non-integrated systems
Report and re-evaluate results
  • Auditor can log into Vanta to see history of all completed access reviews
  • Internals can see status of reviews in progress and also historical review detail

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