OpenAPITools/openapi-generator

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OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec (v2, v3)

Stars: 26.8k
Forks: 7.7k
Open beginner issues: 49
Indexed issues: 5.1k
Avg merge: 1d 6h
Merged PRs (30d): 100

Dominant language: Java
License: Apache-2.0
Last GitHub push: Sep 20, 2026
Latest indexed: Sep 21, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted hacktoberfest good first issue

Beginner friendly Everything

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49 beginner-friendly issues open

[BUG][KOTLIN] Jackson3 option does not discover modules like Jackson2 does Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 88/100

OpenAPITools/openapi-generator#24859 · Opened Sep 3, 2026
Java generator: parameter defaultValue not escaped in @param Javadoc, breaks compilation for values containing "*/" Open

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

OpenAPITools/openapi-generator#24852 · 1 comment · Opened Sep 3, 2026
[BUG][KOTLIN] Fails to compile after updating to 7.25.0 with useJackson3=false useSpringBoot4=true Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

OpenAPITools/openapi-generator#24842 · 1 comment · Opened Sep 2, 2026
[REQ][typescript-axios] Add TypeScript 6 to generated package.json peer range Open

Difficulty 2/5 1-3 hours Newbie friendliness 86/100

OpenAPITools/openapi-generator#24830 · Opened Sep 1, 2026
[BUG][R] Generated samples/client/echo_api/r cannot be run Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

OpenAPITools/openapi-generator#24816 · 1 comment · Opened Aug 31, 2026
[BUG][JAVA] Deprecated @Valid on DTO getter for an attribute that is a container (List, ...) Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 74/100

OpenAPITools/openapi-generator#24782 · Opened Aug 26, 2026
[BUG][Java][Spring] Always generate the default constructor if it is the only constructor Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 82/100

OpenAPITools/openapi-generator#24747 · 2 comments · Opened Aug 20, 2026
[BUG][Java][Spring] Generated code fails Error Prone UnnecessaryFinal bug pattern Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#24744 · Opened Aug 20, 2026
[BUG][JAVA][SPRING] Fluent model setters for deprecated properties are not annotated with @Deprecated Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 84/100

OpenAPITools/openapi-generator#24704 · Opened Aug 14, 2026
[BUG][JAVA] useSpecify=true does not generate package-info.java for <invokerPackage>.auth Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

OpenAPITools/openapi-generator#24664 · 1 comment · Opened Aug 10, 2026
[BUG][typescript-fetch] Missing XxxFromJSON import when discriminator child is also a property type Open

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

OpenAPITools/openapi-generator#24654 · Opened Aug 10, 2026
[BUG][KOTLIN][RESTCLIENT] Multiple consumes media types overwrite Content-Type header, last one always wins Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

OpenAPITools/openapi-generator#24500 · 1 comment · Opened Jul 27, 2026
[BUG][JAVA][gson] CustomTypeAdapterFactory throws "Not a JSON Object:null" for null additionalProperties values Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 84/100

OpenAPITools/openapi-generator#24393 · Opened Jul 23, 2026
[BUG][csharp][generichost] Wrong error type used during deserialization Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 82/100

OpenAPITools/openapi-generator#24345 · Opened Jul 19, 2026
[REQ][RUST] Update template generated version of bon for option `useBonBuilder` Open

Enhancement: Feature

Difficulty 2/5 1-3 hours Newbie friendliness 62/100

OpenAPITools/openapi-generator#24312 · 1 comment · Opened Jul 15, 2026
[BUG][Kotlin][Spring] Option `useSpringBuiltInValidation` is not implemented Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

OpenAPITools/openapi-generator#23950 · Opened Jun 5, 2026
Julia template: `eval` of `parse` anti-pattern Open

Difficulty 2/5 1-3 hours Newbie friendliness 78/100

OpenAPITools/openapi-generator#23941 · 2 comments · Opened Jun 3, 2026
[BUG] rust-server: client feature missing lazy_static and regex deps when models use pattern validation Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#23920 · 1 comment · Opened Jun 1, 2026
[REQ] [Java] Add annotation Generated in Enum Open

Enhancement: Feature

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#23832 · 3 comments · Opened May 20, 2026
[BUG] protobuf-schema generator wraps standalone enums in message types but does not update field references Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

OpenAPITools/openapi-generator#23559 · 4 comments · Opened Apr 15, 2026
[BUG] [CSHARP] [GENERICHOST] OptionProperty.mustache and JsonConverter.mustache use different `Option<T>` nullability handlings. Open

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#23530 · 1 reaction · Opened Apr 13, 2026
[BUG] [typescript-axios] Duplicate identifier 'options' when URL parameter 'options' exists Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#23456 · Opened Apr 7, 2026
[BUG][JAVA] MergedSpec is not created correctly on Windows with inputSpecRootDirectory and nested directories Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

OpenAPITools/openapi-generator#23337 · Opened Mar 24, 2026
[BUG][CPP] cpp-oatpp-client: kebab-case enum values generate invalid function names Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

OpenAPITools/openapi-generator#23227 · Opened Mar 13, 2026
[BUG][cpp-restsdk] key-type of a map is hardcoded to utility::string_t Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#23018 · Opened Feb 20, 2026
Consider limiting message size for exceptions thrown from DefaultGenerator.processOperation Open

Enhancement: Feature

Difficulty 2/5 1-3 hours Newbie friendliness 62/100

OpenAPITools/openapi-generator#22557 · Opened Dec 17, 2025
[BUG][Java] ServerConfiguration is not included in imports when generating from simple OpenAPI file Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

OpenAPITools/openapi-generator#22238 · 3 reactions · Opened Oct 28, 2025
[BUG][CSHARP] Multiple OAuth Flows generates C# code that doesn't compile Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 76/100

OpenAPITools/openapi-generator#22189 · Opened Oct 20, 2025
[BUG] [C] _convertToJSON returns NULL if field is numeric and has value 0 Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#21812 · Opened Aug 25, 2025
[BUG] [typescript] @export is not a valid jsdoc decorator Open

Issue: Bug

Difficulty 1/5 Under an hour Newbie friendliness 78/100

OpenAPITools/openapi-generator#21753 · 1 reaction · Opened Aug 14, 2025
[BUG] [Java] Invalid code generation for anyOf types Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#21433 · 2 reactions · Opened Jun 18, 2025
[REQ] Generated python code should be checked with `mypy --strict` - currently only tested with `mypy` Open

Enhancement: Feature

Difficulty 1/5 Under an hour Newbie friendliness 68/100

OpenAPITools/openapi-generator#20959 · Opened Mar 24, 2025
Better/more examples of ReplaceAll lambda needed Open

Difficulty 1/5 Under an hour Newbie friendliness 62/100

OpenAPITools/openapi-generator#20539 · 1 reaction · Opened Jan 24, 2025
[REQ] Generate Spring HTTP Interface with configurable URL placeholder via Spring properties Open

Enhancement: Feature

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#19120 · 5 reactions · Opened Jul 9, 2024
implicit conversion of symbol to string error in TypeScript-Aurelia template ts(2731) Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 70/100

OpenAPITools/openapi-generator#17253 · Opened Nov 30, 2023
[BUG] `ApiClient.kt.mustache` calls `.toString()` method on a `ByteArray` when building multipart request Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 62/100

OpenAPITools/openapi-generator#16901 · 4 comments · Opened Oct 25, 2023
APITest doesn't compile if the return type is a File Open

Issue: Bug

Difficulty 1/5 Under an hour Newbie friendliness 68/100

OpenAPITools/openapi-generator#14760 · Opened Feb 20, 2023
[BUG] [typescript-fetch] Compile error when using "noImplicitOverride" in tsconfig and ES2022 Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#14515 · 3 comments · 21 reactions · Opened Jan 24, 2023
[REQ][typescript-fetch] Add the API version string as a constant. Open

Enhancement: Feature

Difficulty 2/5 1-3 hours Newbie friendliness 65/100

OpenAPITools/openapi-generator#13935 · Opened Nov 7, 2022
[Kotlin] Models with "additionalProperties" result in invalid Kotlin code Open

Difficulty 2/5 1-3 hours Newbie friendliness 72/100

OpenAPITools/openapi-generator#13395 · 4 comments · Opened Sep 9, 2022
[BUG][typescript-fetch] OAuth header should start with "Bearer" Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#12514 · 2 comments · Opened Jun 2, 2022
[BUG] [typescript-axios] URL search parameters include global object functions Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#12363 · Opened May 13, 2022
[BUG] parsing application/problem+json when use typescript generated PromiseApis Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 65/100

OpenAPITools/openapi-generator#11099 · 1 comment · 2 reactions · Opened Dec 13, 2021
[BUG] [kotlin-spring] kotlin-spring generator creates wrong filenames for controller classes Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#10670 · 1 comment · Opened Oct 23, 2021
[BUG] Typo in PHP composer.mustache "description" section Open

Issue: Bug

Difficulty 1/5 Under an hour Newbie friendliness 68/100

OpenAPITools/openapi-generator#10029 · 2 comments · Opened Jul 24, 2021
[SCALA] Play-Server updated dependencies Open

Difficulty 1/5 Under an hour Newbie friendliness 65/100

OpenAPITools/openapi-generator#7394 · Opened Sep 11, 2020
[Java][WebClient] Missing Spring dependency in build.gradle Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 68/100

OpenAPITools/openapi-generator#6739 · Opened Jun 21, 2020
[BUG][SPRING] delegateController: The annotation @Autowired is disallowed for this location Open

Issue: Bug

Difficulty 2/5 1-3 hours Newbie friendliness 64/100

OpenAPITools/openapi-generator#4329 · Opened Oct 30, 2019
[REQ] Recreate directories in Ruby client samples by .bat file Open

Enhancement: Feature

Difficulty 2/5 1-3 hours Newbie friendliness 62/100

OpenAPITools/openapi-generator#2498 · Opened Mar 25, 2019

OpenAPITools/openapi-generator

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