This page compiles case studies of podlings that have undergone the Apache Incubator process.
Each example shows different outcomes: healthy graduations, rapid success, recoveries, stagnation, retirement, withdrawal, and unique challenges such as vendor dominance or global contributor bases.
The goal is to help mentors, podlings, and the Incubator PMC learn from past experiences.
Entry
Created at LinkedIn (2013), open-sourced in 2015.
Entered the Apache Incubator in 2018.
During Incubation
Releases: First Apache release in 2019, followed by a steady cadence through 2020.
Community growth: Attracted contributors from Uber, StarTree, and independent volunteers beyond LinkedIn.
Process adoption: Early reliance on Slack/GitHub for discussions was shifted toward dev@ lists for decision-making.
Mentorship: Mentors emphasized mailing list transparency and release discipline.
Adoption: Widely used in industry (LinkedIn, Uber, Stripe, Walmart, DoorDash).
Graduation
Takeaway
Pinot shows that podlings with strong corporate origins can graduate successfully if they:
Attract contributors from outside the founding company,
Deliver consistent ASF-compliant releases, and
Embed transparency and consensus in their processes.
Entry
Originated at Google as “Wave in a Box.”
Entered the Apache Incubator in 2010.
During Incubation
Community stagnation: Most contributions came from a small set of ex-Google engineers; few new committers joined.
Releases: Rare and inconsistent; struggled with ASF release mechanics.
Culture: Much discussion remained off-list; limited adoption of ASF decision-making norms.
Mentorship: Repeated IPMC concerns about diversity and sustainability.
Retirement
Takeaway
Even a high-profile donation can fail if a podling does not establish a sustainable, diverse community and adopt an ASF-style transparency approach.
Entry
Created at Airbnb.
Entered the Apache Incubator in 2017.
During Incubation
Early struggles: Development focused on GitHub; mailing list culture was weak. The first incubating release didn’t arrive until 2019.
Mentorship: Mentors and IPMC pressed the podling to rotate release managers and move decisions on-list.
Recovery: By 2020, the community had diversified beyond Airbnb, improved mailing list engagement, and established a monthly release cadence.
Graduation
Graduated in 2020, the TLP announcement was made in early 2021.
Takeaway
Superset shows that a podling can recover from weak starts if mentors persist, the community adopts ASF release discipline, and decision-making shifts to transparent forums.
Entry
Originated as the Stratosphere research project at TU Berlin.
Entered the Apache Incubator in 2014.
During Incubation
Releases: The First incubating release was shipped the same year.
Community: Already had strong multi-organization contributors and a clear academic-to-industry transition.
Culture: Adopted mailing list governance and voting practices immediately.
Graduation
Takeaway
Flink demonstrates that incubation can be very short when a project enters with an existing, well-organized, and diverse community that quickly adopts ASF practices.
Entry
Created at Netflix and donated to the ASF.
Entered the Apache Incubator in 2018.
During Incubation
Community growth: Quickly attracted contributors from Apple, Alibaba, Adobe, LinkedIn, and independents.
Releases: Produced multiple incubating releases beginning in 2019.
Ecosystem impact: Broad adoption via integration into Spark, Flink, and Trino attracted new contributors.
Mentorship: Mentors emphasized branding and vendor-neutral governance.
Graduation
Takeaway
Iceberg shows that projects with strong corporate origins can graduate healthily when they diversify, deliver ASF-compliant releases, and maintain vendor neutrality.
Entry
Search engine built on Lucene.
Entered the Apache Incubator in 2012.
During Incubation
Very little mailing list or release activity.
The community never grew beyond a handful of individuals.
Repeated IPMC concerns about the lack of progress.
Retirement
Takeaway
Blur shows that inactivity and failure to build a community inevitably lead to retirement, no matter how promising the technology.
Entry
Originally developed at the University of Washington, it was later heavily backed by AWS.
Entered the Apache Incubator in 2017.
During Incubation
Releases: Produced multiple incubating releases in the 1.x series under the ASF process.
Community growth (limited): The most active committers and release managers were primarily AWS employees.
ASF culture challenges: Development leaned heavily on GitHub; ASF mailing list activity was limited.
Mentorship: IPMC concerns persisted about single-vendor dominance and sustainability.
Graduation
After Graduation
Contributor diversity did not improve significantly.
Declining activity led the ASF Board to approve retirement.
Retirement: The project was moved to the Apache Attic in 2023.
Takeaway
MXNet illustrates the risks of vendor dominance. Even with:
A strong technical foundation,
Widespread industry adoption, and
Corporate backing,
a project cannot thrive at Apache without multi-organization contributor diversity, mailing list–based consensus, and shared governance.
Entry
Created at Airbnb in 2014 as a workflow orchestration system.
Entered the Apache Incubator in 2016.
During Incubation
Releases: Began producing incubating releases in 2016; later established a steady cadence.
Community growth: Quickly broadened participation beyond Airbnb — contributors from Google, Polidea, and independents became committers.
Governance: Shifted all decision-making onto dev@ mailing lists.
Ecosystem impact: Widely adopted in data engineering; integrations accelerated growth.
Mentorship: Mentors emphasized neutrality and rotating release managers.
Graduation
Takeaway
Airflow illustrates how a project that begins at a single company can evolve into a vibrant, multi-organization community. Keys to success:
Rotating release managers,
Strong mailing list culture, and
Early outreach beyond the founding org.
Entry
Distributed tracing system, originally created at Twitter in 2012.
Entered the Apache Incubator in 2018.
During Incubation
Community context: An established ecosystem already existed under the OpenZipkin GitHub organisation.
Challenges: Development and issue tracking remained primarily in the external GitHub organisation; ASF mailing lists were underutilised.
Releases: No incubating ASF releases were produced.
Mentorship: Concerns were raised about lack of ASF alignment (releases, infra, governance).
Outcome
After ~3 years without progress toward graduation, the community voted to withdraw from the Incubator in 2021.
Development continues outside Apache.
Takeaway
Zipkin illustrates that incubation is a trial fit. Sometimes, even a popular project discovers that the ASF model is not the right home. In such cases, withdrawal is the right outcome.
Entry
Donated by HP as a transactional SQL-on-HBase database.
Entered the Apache Incubator in 2015.
During Incubation
Produced multiple incubating releases in 2016–2017.
Demonstrated governance maturity and readiness.
Graduation
After Graduation
Contributor diversity remained limited.
Activity slowed.
Retirement: Project retired to the Attic in 2021.
Takeaway
Graduating is not sufficient for survival. Without long-term diversity and a steady inflow of contributors, even graduated TLPs may be retired.
Entry
Long-standing IDE, originally from Sun Microsystems, later maintained by Oracle.
Donated by Oracle and entered the Apache Incubator in 2016.
During Incubation
IP clearance and migration: Millions of lines of code required extensive clearance and migration.
Releases: First Apache release was NetBeans 9.0 in 2018, nearly two years after entry.
Community growth: Built governance under ASF norms; contributors beyond Oracle became more active.
Mentorship: Guided the project in adapting workflows to ASF mailing list and release practices.
Graduation
Takeaway
NetBeans shows that incubation isn’t just for new projects — even mature, widely used codebases need to:
Complete IP clearance at ASF standards,
Transition governance to the ASF lists, and
Prove they can make ASF-compliant releases.
Entry
JavaScript-based data visualization library, created at Baidu.
Entered the Apache Incubator in 2018.
During Incubation
Community growth: Diversified beyond Baidu to include universities, tech companies, and international developers.
Language and inclusivity: Early contributors mostly used Chinese; mentors emphasized moving official decisions to English-language ASF lists for transparency and inclusivity.
Releases: Produced multiple incubating releases under the ASF process.
Governance: Mailing list culture matured, shifting from external/private channels to ASF infrastructure.
Outreach: Documentation has been expanded in both English and Chinese.
Graduation
Takeaway
ECharts demonstrates that ASF incubation is effective for globally popular projects, even when most contributors initially start out in a non-English language environment. Inclusivity and multilingual practices are vital for sustaining global diversity.