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Personal Finance · head to head

Firefly III vs Kong

Firefly III logo

Firefly III

Personal Finance

Free, open source, self-hosted personal finance manager with double-entry style accounting

From
Free
Rated
-
Full reviewWebsite
Kong logo

Kong

APIs

Cloud-native API gateway and service connectivity platform

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Firefly III there is no official managed hosting, so a non-technical user has no easy on-ramp the way Actual Budget offers with its paid hosted sync.; Kong the Plus plan includes 1M API requests a month and charges $200 a month for each additional million
  • They diverge on capability: Firefly III covers Double-entry style ledger, Kong covers API Gateway.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which Firefly III and Kong actually diverge.

Attributes where Firefly III and Kong differ
AttributeFirefly IIIKong
Pricing modelOpen source, no licence feesubscription
PlatformsWeb, Linux, DockerLinux, Docker, Kubernetes
CategoryPersonal FinanceAPIs
FoundedUnknown2010

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 Firefly III

  • Double-entry style ledger
  • Multi-currency accounts
  • Bill and subscription tracking
  • Rule engine
  • Reports and charts
  • API access

Only in Kong

  • API Gateway
  • Authentication & Authorization
  • Rate Limiting
  • Kubernetes
  • Consul
  • Eureka
  • PostgreSQL
  • Linux support

What people use each for

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

Firefly III

  • A self-hoster already running a home server or NAS who wants their financial ledger on the same infrastructurenot Kong
  • Someone who wants double-entry style accuracy rather than simple envelope budgetingnot Kong
  • A privacy-focused user who refuses to put financial data on any third-party server, hosted or otherwisenot Kong
  • A developer who wants API access to build custom bank import scripts for accounts with no standard connectornot Kong

Kong

  • API gateway management and routingnot Firefly III
  • API development and testingnot Firefly III
  • Enterprise API security and governancenot Firefly III

Where each one falls short

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

Firefly III

  • There is no official managed hosting, so a non-technical user has no easy on-ramp the way Actual Budget offers with its paid hosted sync.
  • The double-entry-influenced model is less intuitive for newcomers than simple envelope budgeting, and the learning curve is real.
  • Automatic bank sync depends on the community-run importer and third-party connectors, and coverage and reliability vary a lot by bank and country.
  • Mobile access is via a web interface rather than a polished native app, which is a step behind Actual Budget or Lunch Money on phones.
  • Because there is no company behind it, security patching and feature development depend entirely on volunteer maintainer time.

Kong

  • The Plus plan includes 1M API requests a month and charges $200 a month for each additional million
  • Plus is capped at 10M requests a month, so growth past that forces an Enterprise contract
  • Plus limits published APIs to 20 and includes one Developer Portal, with a second at $200 a month
  • SSO and audit logging are Enterprise only
  • Enterprise pricing is custom and billed annually

Pricing, plan by plan

Firefly III

Free
  • Firefly IIIFree
    • Full functionality, self-hosted
    • No usage limits
    • Community support, donations accepted

Kong

Free
  • Kong Konnect Free TrialFree
    • 30-day free trial
    • Full enterprise functionality
    • Unlimited gateways
  • Kong Konnect Plus$null/month
    • Per gateway pricing billed monthly
    • Up to 5 Serverless Gateways, 2 Hybrid, 2 Dedicated Cloud Gateways
    • 1M API requests included per month
  • Kong Insomnia EssentialsFree
    • Unlimited projects and CLI access
    • Up to 3 Git Sync users
    • 1,000 mock server requests per month
  • Kong Insomnia Pro$12/month
    • Unlimited users with Git Sync access
    • Unlimited organizations
    • RBAC

Which should you pick?

Choose Firefly III if

  • You need double-entry style ledger.
  • You want to start without paying.
  • You work on Web, Linux, Docker.
  • You also want multi-currency accounts.
Firefly III review

Choose Kong if

  • You need api gateway.
  • You want to start without paying.
  • You work on Linux, Docker, Kubernetes.
  • You also want authentication & authorization.
Kong review

Questions people ask

Is Firefly III or Kong better?
Neither clearly leads. Firefly III starts at Free and Kong at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Firefly III or Kong?
Firefly III starts at Free and Kong at Free.
Does Firefly III or Kong run on more platforms?
Firefly III runs on Web, Linux, Docker. Kong runs on Linux, Docker, Kubernetes.
Can I use Firefly III for free?
Both have a free tier, so you can try either at no cost before committing.
What is Firefly III best used for?
Firefly III is most often used for a self-hoster already running a home server or nas who wants their financial ledger on the same infrastructure, someone who wants double-entry style accuracy rather than simple envelope budgeting, a privacy-focused user who refuses to put financial data on any third-party server, hosted or otherwise, a developer who wants api access to build custom bank import scripts for accounts with no standard connector. Of those, a self-hoster already running a home server or nas who wants their financial ledger on the same infrastructure and someone who wants double-entry style accuracy rather than simple envelope budgeting are not what Kong is typically brought in for.
What can Firefly III do that Kong cannot?
Firefly III covers Double-entry style ledger, Multi-currency accounts, Bill and subscription tracking, Rule engine. Kong covers API Gateway, Authentication & Authorization, Rate Limiting, Kubernetes.

Answered from the vendors’ own pages

Firefly III: Can I pay someone to host Firefly III for me?

Not through the core project; some third-party providers sell Firefly III hosting independently, but there is no official managed service.

Kong: Does Kong offer a free trial?

Yes, Kong Konnect offers a 30-day free trial with full enterprise functionality, unlimited gateways, and no credit card required.

Source
Firefly III: Does it support multiple currencies?

Yes, natively, including accounts and transactions in different currencies.

Kong: How much does Kong Insomnia Pro cost?

Kong Insomnia Pro is $12 per user per month with 15% savings available for annual billing.

Source
Firefly III: Is it really free with no paid tier?

Yes, the software is free and open source under the AGPL; the project accepts donations but sells nothing.

Kong: What are Kong Konnect Plus API request limits?

Kong Konnect Plus includes 1M API requests per month; additional requests cost $200 per 1M (maximum 10M per month).

Source
Kong: What is included in Kong Insomnia Enterprise?

Kong Insomnia Enterprise is $45 per user per month with SSO, SCIM, vault integrations, unlimited mock server requests, and Konnect integration.

Source
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