[Multiple languages] properties are generated as nullable/optional, despite required/nullable usage in OAS schema

Kiota ignores the usage of `required`/`nullable` in OAS schemas. C# properties are always generated as nullable. This results in unneeded noisy squiggles, as shown [here](https://github.com/microsoft/kiota/issues/3846#issuecomment-1844249797). NSwag does a better job, by performing the following translation (using the `/GenerateNullableReferenceTypes:true` switch): - OAS non-required + nullable: C# nullable - OAS required + nullable: C# nullable - OAS non-required + non-nullable: C# non-nullable, unless combined with the `/GenerateOptionalPropertiesAsNullable:true` switch - OAS required + non-nullable: C# non-nullable Additionally, NSwag adds `[Newtonsoft.Json.JsonProperty(Required = ..., , NullValueHandling = ...)]` on the generated properties, which results in client-side serialization errors (thus avoiding a server roundtrip on invalid input). Example component schema ```json "exampleComponent": { "required": [ "requiredNonNullableReferenceType", "requiredNullableReferenceType", "requiredNullableValueType", "requiredValueType" ], "type": "object", "properties": { "nonNullableReferenceType": { "type": "string" }, "requiredNonNullableReferenceType": { "type": "string" }, "nullableReferenceType": { "type": "string", "nullable": true }, "requiredNullableReferenceType": { "type": "string", "nullable": true }, "valueType": { "type": "integer", "format": "int32" }, "requiredValueType": { "type": "integer", "format": "int32" }, "nullableValueType": { "type": "integer", "format": "int32", "nullable": true }, "requiredNullableValueType": { "type": "integer", "format": "int32", "nullable": true } }, "additionalProperties": false } ```

GitHubDec 14, 2023ToolDesign & CreativeSource

FL score

out of 100

Verdict

BUILD

high confidence

Competition

competitors found, mature market, funded players

Trend

8 community mentions

A specific C# nullability and required property generation bug in Microsoft Kiota causes developer frustration and potential serialization errors, in a market saturated with free tools that already solve this correctly.

The pain

Kiota (Microsoft's API client generator) incorrectly generates C# properties as always nullable/optional, ignoring OpenAPI schema's `required` and `nullable` flags. This leads to 'noisy squiggles' in code and potentially critical client-side serialization errors, wasting developer time and introducing bugs.

The gap

The gap is specific to Kiota users; the broader market has mature tools (NSwag, OpenAPI Generator) that correctly handle this. For Kiota users, the gap is Kiota's own inability to correctly interpret the spec, creating an underserved niche *within* the Kiota ecosystem. Competitors prove demand for *correct* generation.

Build angle

The most viable build angle for a solo builder is a targeted post-processor or plugin for Kiota-generated C# code, which automatically corrects the nullability and required property attributes based on the original OpenAPI schema. This avoids needing to build a full generator from scratch.

Strengths

Highly specific and real problem for Kiota C# users, evidenced by GitHub issues and recent discussions.
Clear, measurable value proposition: eliminate squiggles and prevent serialization bugs.

Questions about this idea?

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Fly Labs Method

Is the pain real, is there a gap, is it the right time, can one person build it.

Problem clarity: 26
Solution gap: 16
Willingness to pay: 12
Buildability: 11

A real, specific problem within the Kiota ecosystem causing developer frustration and potential bugs, but it's a known issue that mature OSS tools already solve. Building a robust solution as a solo builder quickly will be challenging, and monetization signals are weak given the free alternatives.

Value Equation

Dream outcome and how likely it feels, against the time and effort it costs.

A clear problem exists, but the competitive landscape, limited monetization signals, and high build complexity make it a tough market to win and monetize for a solo builder.

One-Person Business

Curiosity pull, identity fit, and a path from free value to paid for a solo creator.

A clear, specific technical problem for a niche audience (Kiota+C# developers), but difficult to monetize given free alternatives and high complexity for a solo builder.

Viral Frameworks

Hook strength, shareability, and how cheaply it can be tested.

A clear value proposition for a specific niche, but monetization and competitive pressures pose significant challenges for a micro-SaaS.

Builder Lens

Evidence the problem exists, timing, defensibility, and a model that fits on a napkin.

A clear problem for a specific developer persona, but a crowded market and difficulty in finding a unique, monetizable wedge for a solo builder.

Why this verdict

The idea addresses a very real and specific pain for a particular developer segment. However, the market context is challenging: the broader problem is already solved by numerous free and mature tools, and Kiota itself is a Microsoft-backed project that *should* fix this. Monetization for such a specific bug fix, without a wider value proposition or a strong differentiating factor, is highly uncertain. A solo builder would need to validate the willingness to pay very carefully and consider the risk of Kiota making its own fix. Therefore, extensive validation is required before committing to a full build, focusing on whether Kiota users would truly pay for this specific solution rather than switching tools or waiting.

Five lenses, one composite. How scoring works

The angle

This weekend

Conduct in-depth interviews with Kiota C# developers to understand their exact pain points, frequency, and if they've considered paying for a solution or alternative.
Validate if Kiota users would pay for a targeted post-processor, even a small amount, given the free alternatives.
Explore potential for a 'buy me a coffee' model or integrate the fix into a broader, more valuable developer tooling suite.
Build a proof-of-concept (POC) post-processor and share it with the Kiota community to gather feedback and gauge adoption interest before committing to a full product.

Who is already there, mature market

OpenAPI Generator
Open-source tool that generates API client libraries in over 50 languages from OpenAPI 3.0 schemas, properly handling required and nullable properties based on schema definitions.<grok:render type="render_inline_citation"><argument name="citation_id">19</argument></grok:render><grok:render type="render_inline_citation"><argument name="citation_id">30</argument></grok:render>
Pricing: free
NSwag
.NET-focused OpenAPI toolchain for generating clients and servers, supports nullable reference types and required fields correctly.<grok:render type="render_inline_citation"><argument name="citation_id">35</argument></grok:render>
Pricing: free
SpeakeasyFunded
Modern SDK generator from OpenAPI specs for multiple languages (TypeScript, Python, etc.), praised for reliable type handling and stability in SDK generation.<grok:render type="render_inline_citation"><argument name="citation_id">16</argument></grok:render>
Pricing: free tier / OSS program / paid enterprise
AutoRestVisit
A tool that generates client libraries for interacting with RESTful web services, requiring an OpenAPI specification. It supports various languages, including C#, Java, Python, TypeScript, and Go.
Pricing: Open-source
Blackbird API DevelopmentVisit
An AI-powered platform to accelerate API development with code generation, mocking, and on-demand testing environments.
Pricing: $69/month
Claude CodeFundedVisit
A developer-focused AI tool that assists with coding tasks, understands full features, repositories, and workflows, and can refactor code, run tests, and debug.
Pricing: $20/month (included in Anthropic's Pro and Max plans)
Lingma (Alibaba Cloud's AI-driven coding assistant)FundedVisit
An AI-driven coding assistant offering real-time code completion, natural language-based code generation, and smart troubleshooting across over 200 programming languages.
Pricing: Not explicitly stated, likely part of Alibaba Cloud services

Funded players

Gaps they leave open

Limited multi-language support in some tools
Occasional schema edge-case bugs
Less focus on advanced serialization like Kiota

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[Multiple languages] properties are generated as nullable/optional, despite required/nullable usage in OAS schema

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