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Technology · head to head

Heap vs Nixpacks

Heap logo

Heap

Technology

Product analytics for the modern product team

From
Free
Free plan
Yes
Full reviewWebsite
Nixpacks logo

Nixpacks

Developer Tools

Build system that turns a source directory into an OCI image, now in maintenance mode

From
Free
Free plan
Yes
Full reviewWebsite

The short version

  • Each has a real cost: Heap no built-in A/B testing or feature flags; requires integration with separate tools for experimentation; Nixpacks the project is in maintenance mode with no commits on the default branch since May 2026 and no release since October 2025, so support for new language versions arrives only if someone forks it.
  • They diverge on capability: Heap covers Autocapture, Nixpacks covers Automatic language detection.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Heap and Nixpacks actually diverge.

Attributes where Heap and Nixpacks differ
AttributeHeapNixpacks
Pricing modelUnknownOpen source, no licence fee
PlatformsWeb, iOS, AndroidLinux, macOS, CLI, Docker
CategoryTechnologyDeveloper Tools
Founded2013Unknown

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Heap

  • Autocapture
  • Retroactive analytics
  • Session replay
  • Funnel analysis
  • User segmentation
  • Path analysis
  • Data science
  • Virtual events

Only in Nixpacks

  • Automatic language detection
  • No Dockerfile required
  • Nix toolchains
  • Configuration escape hatches
  • Docker layer caching

What people use each for

The jobs each tool is most often brought in to do.

Heap

  • User behavior analysisnot Nixpacks
  • Conversion optimizationnot Nixpacks
  • Product adoptionnot Nixpacks
  • Customer journey mappingnot Nixpacks
  • A/B testing analysisnot Nixpacks

Nixpacks

  • Understanding the build behaviour of a platform that adopted Nixpacks before it was frozennot Heap
  • Producing container images from a polyglot monorepo where nobody wants to own several Dockerfilesnot Heap
  • Reproducing an existing Railway build locally while planning a migration to Railpacknot Heap
  • Comparing what a Nix based builder does differently from a buildpack before choosing a successornot Heap

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Heap

  • No built-in A/B testing or feature flags; requires integration with separate tools for experimentation
  • Group analytics and advanced features require a sales conversation, not self-serve
  • Cloud-only deployment; no self-hosted option for data security or compliance requirements
  • Session replay lacks developer debugging tools compared to PostHog
  • Pricing for Growth and Pro plans requires direct sales contact; no transparency on how pricing scales

Nixpacks

  • The project is in maintenance mode with no commits on the default branch since May 2026 and no release since October 2025, so support for new language versions arrives only if someone forks it.
  • Build determinism is softer than it appears, because providers pin a nixpkgs archive commit and bumping that archive silently moves compiler and runtime versions underneath a build that looks unchanged.
  • Caching is limited to Docker layers rather than a content addressed graph, so a small change early in the build invalidates everything after it, which is exactly the limitation Railpack was rewritten to fix.
  • Images carry Nix store layers and come out larger than an equivalent tuned Dockerfile or buildpack output, which costs registry storage and slows cold pulls on scale-out.
  • There is no specification, no vendor neutral governance and no third party provider ecosystem, so a single company was able to redirect strategy and leave every downstream user with a frozen build tool.

Pricing, plan by plan

Heap

Free
  • FreeFree
    • Up to 10,000 monthly sessions
    • Basic charts
    • 6 months data history
  • Growth$undefined/custom
    • Custom session pricing
    • Sense AI assistant
    • 12 months data history
  • Pro$undefined/custom
    • Custom session pricing
    • Account analytics
    • Engagement matrix
  • Premier$undefined/custom
    • Custom session pricing
    • Data warehouse integration
    • Unlimited projects

Nixpacks

Free
  • NixpacksFree
    • MIT licensed, no usage limits
    • No commercial edition and no support contract
    • In maintenance mode, superseded by Railpack

Which should you pick?

Choose Heap if

  • You need autocapture.
  • You want to start without paying.
  • You work on Web, iOS, Android.
  • You also want retroactive analytics.
Heap review

Choose Nixpacks if

  • You need automatic language detection.
  • You want to start without paying.
  • You work on Linux, macOS, CLI, Docker.
  • You also want no dockerfile required.
Nixpacks review

Questions people ask

Is Heap or Nixpacks better?
Neither clearly leads. Heap starts at Free and Nixpacks at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Heap or Nixpacks?
Heap starts at Free and Nixpacks at Free.
Does Heap or Nixpacks run on more platforms?
Heap runs on Web, iOS, Android. Nixpacks runs on Linux, macOS, CLI, Docker.
Can I use Heap for free?
Both have a free tier, so you can try either at no cost before committing.
What is Heap best used for?
Heap is most often used for user behavior analysis, conversion optimization, product adoption, customer journey mapping. Of those, user behavior analysis and conversion optimization are not what Nixpacks is typically brought in for.
What can Heap do that Nixpacks cannot?
Heap covers Autocapture, Retroactive analytics, Session replay, Funnel analysis. Nixpacks covers Automatic language detection, No Dockerfile required, Nix toolchains, Configuration escape hatches.

Answered from the vendors’ own pages

Heap: What does Heap's autocapture feature do?

Heap's autocapture is a single code snippet that automatically captures every click, swipe, tap, pageview, and form fill on your website and apps without requiring manual event setup. Once installed, Heap captures the entire digital experience of every user on every platform with no ongoing engineering maintenance needed.

Source
Nixpacks: Should I start a new project on Nixpacks?

No. The documentation and README both say it is in maintenance mode and recommend Railpack. Choose Railpack, Cloud Native Buildpacks or a Dockerfile instead.

Heap: What are Heap's pricing plans and how much do they cost?

Heap offers a Free plan for up to 10,000 monthly sessions. Growth, Pro, and Premier plans use custom session-based pricing that requires contacting sales for a quote. Free includes basic charts and 6 months data history. Growth adds the Sense AI assistant. Pro adds account analytics. Premier adds data warehouse integration and dedicated customer success management.

Source
Nixpacks: Will my existing Nixpacks builds stop working?

Not immediately. Pinned nixpkgs archives keep resolving, so builds continue. What you lose is support for new runtime major versions and any fix for a provider bug.

Heap: Does Heap include session replay and A/B testing?

Heap includes integrated session replay showing exactly what users did on your site. However, Heap does not include built-in A/B testing or feature flags. Teams requiring these capabilities must use separate tools or integrate with third-party platforms.

Source
Nixpacks: What replaces it?

Railpack, also from Railway and also MIT licensed, rebuilt as a BuildKit custom frontend for finer grained caching and parallel steps.

Heap: What integrations does Heap support?

Heap supports over 100 integrations connecting to business tools including marketing platforms, CRMs, and data warehouses. This allows insights to reach relevant teams and ensures data flows to other business systems automatically.

Source
Nixpacks: Is it still open source?

Yes, MIT, and the repository is not archived. Being open source does not help much when nobody is merging provider updates.

Heap: Does Heap offer self-hosting or is it cloud-only?

Heap is cloud-only and does not offer self-hosted options. Organizations requiring on-premises deployment should consider alternatives like PostHog which supports self-hosting alongside its cloud product.

Source
Heap: What is Sense and how does it help with analytics?

Sense Chat is Heap's AI assistant that enables users to access analytics without extensive technical knowledge. It allows teams to ask questions about user behavior and get answers directly without lengthy onboarding or technical expertise, making insights more accessible to non-technical stakeholders.

Source
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