AI visibility report
Fern ranks #3 in Documentation & Developer Portals AI search.
Outside the top three on 13 of the 25 prompts buyers actually ask.
Mintlify is cited on 11 of those losses.
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Track Fern across these prompts daily.
Start free trial#3 among 11 vendors · still absent from 80.7% of tracked prompt responses
Top-3 citations across 150 prompt × platform pairs
Peer Ranking
Key Metrics
Platform Breakdown
Grok
Google AI Mode
Gemini Search
ChatGPT
Perplexity
Bing CopilotVisible, but narrative can improve. Fern ranks #3 on presence but #4 on sentiment. The brand appears relatively often, but competitors may be getting more favorable language when they appear.
Where Fern is losing
Prompts where competitors are visible and Fern is not.
These prompt-level losses are the first prompts to track and repair.
Where Fern is winning5
Looking for a documentation platform that supports embedded API playgrounds, diagrams, and interactive tutorial flows — what are my options beyond basic markdown?
Avg # 1.0 · 1 platform
Which developer documentation platforms make it easiest to white-label with a custom domain and brand styles for a B2B SaaS product?
Avg # 1.0 · 1 platform
Which documentation platforms offer the best analytics — page visits, drop-off points, and search queries from developer users?
Avg # 2.0 · 1 platform
Which documentation platforms support a docs-as-code workflow where engineers write in markdown, review in pull requests, and auto-publish on merge?
Avg # 2.8 · 4 platforms
Which developer portal platforms offer semantic search rather than just keyword matching across docs?
Avg # 3.0 · 1 platform
Where Fern is losing5
Which documentation platforms have the best native integration with OpenAPI, AsyncAPI, and GraphQL schemas for auto-generating reference docs?
Competitors on 4 platforms
Track this promptWhich documentation platforms offer the best collaboration features so non-technical writers and engineers can work together without friction?
Competitors on 3 platforms
Track this promptWhich developer documentation platforms do engineers actually keep up to date — what makes the writing experience good enough that docs don't become stale?
Competitors on 3 platforms
Track this promptWhich hosted documentation platforms perform best for a global developer audience — CDN coverage and page load times for international users?
Competitors on 2 platforms
Track this promptWhich documentation platforms handle versioned docs for multiple active major versions without duplicating content across v2 and v3?
Competitors on 2 platforms
Track this prompt
Track Fern daily before the next report refresh.
Track these gapsResearch dossierCapabilities, use cases, sources, reviews, pricing, and FAQ
Overview
Fern (Birch Solutions, Inc.) is a developer experience platform that helps API-first companies deliver production-ready SDKs and branded API documentation from a single integrated pipeline. Founded in 2022 and headquartered in Brooklyn, New York, Fern accepts OpenAPI, AsyncAPI, gRPC, and OpenRPC specifications as input, generating idiomatic client libraries in nine programming languages alongside SEO-optimized, customizable documentation websites. Core capabilities include docs-as-code Git workflows, a live API Explorer, AI search, MCP server support for AI-agent readiness, RBAC, and SSO. Backed by $13M from Bessemer Venture Partners and Y Combinator, Fern was acquired by Postman in January 2026 for an undisclosed sum and continues to operate as an independent product. Over 200 customers—including Square, ElevenLabs, Adobe, Auth0, and Twilio—use Fern to power developer and agentic API experiences.
Fern is an integrated API developer experience platform with two core products: the Fern SDK Generator, which produces idiomatic, production-ready client libraries across TypeScript, Python, Go, Java, C#, PHP, Ruby, Swift, and Rust from an API spec; and Fern Docs, a fully customizable API documentation platform supporting docs-as-code, AI search, interactive API Explorer, versioning, RBAC, and enterprise SSO. Both products accept OpenAPI, AsyncAPI, gRPC, and OpenRPC as input and are open source. Fern is a Postman company as of January 2026.
Key Facts
- Founded
- 2022
- HQ
- Brooklyn, New York, USA
- Founders
- Danny Sheridan, Deep Singhvi
- Employees
- <40
- Funding
- $13M
- Customers
- 200+
- Status
- Acquired by Postman (January 2026)
Target users
Key Capabilities10
- SDK generation in 9 languages: TypeScript, Python, Go, Java, C#, PHP, Ruby, Swift, Rust
- Branded API documentation site with custom domain, CSS, JS, and React components
- Multi-spec input: OpenAPI, AsyncAPI, gRPC/Protobuf, OpenRPC, Fern Definition
- Docs-as-code with Git-backed versioning, PR preview deployments, and CI/CD publishing
- Live API Explorer with API key injection and SDK code snippet generation
- AI search (Ask Fern), llms.txt, and MCP server for agent-ready documentation
- Enterprise access controls: RBAC, JWT, SSO, federated authentication
- Built-in SDK features: OAuth 2.0, SSE, auto-pagination, retries with backoff, idempotency headers
- Automated semantic versioning and registry publishing for SDK packages
- SOC 2 Type II compliance and dependency vulnerability SLA
Key Use Cases8
- API-first companies needing idiomatic, production-ready SDKs across multiple languages
- Replacing low-quality open-source SDK generators (e.g., OpenAPI Generator)
- Publishing branded API documentation portals from existing OpenAPI or gRPC specs
- Keeping SDKs and API docs in continuous sync via CI/CD pipelines
- Enterprise developer portals with SSO, RBAC, and self-hosting requirements
- Making API documentation AI-agent-readable (llms.txt, MCP server, agent score)
- Migrating legacy docs from Mintlify, ReadMe, or Docusaurus to a managed platform
- Scaling DX teams by outsourcing SDK maintenance and documentation infrastructure
Fern customer outcomes
$600k saved in engineer salaries
Square adopted Fern for SDK generation after evaluating multiple generators, citing clean language-native code quality and end-to-end partnership on OpenAPI improvements and launch.
700+ pages of content migrated
Fern embedded with LaunchDarkly's docs team, migrated content, and created an information architecture spanning API reference, guides, and SDK reference, freeing the internal team from docs infrastructure.
2 engineers' time freed up annually
Cohere expanded from one SDK to four supported languages using Fern, and uses Fern Docs to generate a documentation website matching Cohere's brand identity.
Fern enabled Candid to adopt API-first development by keeping docs, SDKs, and server implementation synchronized from a single spec via fern generate.
Recent Trend
How AI describes Fern3
Key players include Mintlify, Stoplight, ReadMe, Fern, and Apidog, each with distinct strengths across schemas, interactive playgrounds, and multi-format exports.
Which documentation platforms have the best native integration with OpenAPI, AsyncAPI, and GraphQL schemas for auto-generating reference docs?
Short answer: The leading docs-as-code platforms that support writing in Markdown, PR-based reviews, and auto-publish on merge include GitBook, ReadMe, Fern, Mintlify, ReadMe, and Git-powered solutions like Docusaurus/Hugo pipelines integrated with CI/CD.
Which documentation platforms support a docs-as-code workflow where engineers write in markdown, review in pull requests, and auto-publish on merge?
GitBook Fern GitBook features a powerful toolset called Adaptive Content alongside its Authenticated Access suite.
Which developer documentation portals support content gating — showing different docs to authenticated customers vs. anonymous visitors?
Most cited sources8
20The best API documentation platforms for enterprise teams in May 2026 - Fern: Docs
buildwithfern.com·Blog Post
- 15
Docs-as-Code Solutions for APIs | January 2026 | Fern
buildwithfern.com·Blog Post
- 11
API Developer Portals for Enterprise (Jan 2026) | Fern
buildwithfern.com·Blog Post
- 8
Best API docs for enterprise security March 2026 | Fern
buildwithfern.com·Blog Post
- 8
Self-Hosted Documentation Tools January 2026 | Fern
buildwithfern.com·Documentation
- 8
Best SDK generation tools 2026 | Multi-language APIs | Fern | Fern
buildwithfern.com·Blog Post
Alternatives in Documentation & Developer Portals6
Fern differentiates as the only integrated platform that couples high-quality, language-idiomatic SDK generation with fully branded API documentation from a single API spec.
- Where pure-play docs tools (Mintlify, ReadMe, Redocly, Scalar) cover only documentation, and standalone SDK generators (Stainless) cover only SDKs, Fern positions the two as inseparable—SDKs surface inline docs while docs auto-populate SDK code snippets.
- Enterprise positioning emphasizes white-glove migration, embedded engineering support, and SOC 2 Type II compliance.
- The January 2026 acquisition by Postman adds distribution to 500,000+ Postman organizations, differentiating it further from independent competitors.
Reviews
Praised
- Idiomatic, language-native SDK code quality
- Unified SDK and docs pipeline
- Smooth and fast migrations from legacy platforms
- High-touch, embedded team support
- OpenAPI spec improvement guidance
- Consistent sync between SDKs, docs, and API spec
- Beautiful, brand-matched documentation output
- Agent-readiness and llms.txt support
Criticized
- Per-SDK per-language pricing can escalate for broad language coverage
- Enterprise and Pro pricing requires sales engagement with no public rates
- Endpoint caps on lower SDK tiers
- Swift and Rust generators are newer with less production history
- Limited publicly verifiable third-party review coverage
No independent third-party review platform scores (G2, Gartner Peer Insights, etc.) were found for Fern at the time of research, consistent with its early-stage profile. Customer testimonials published on the Fern website and sourced in press coverage are consistently strong, with customers citing idiomatic code quality, smooth migrations, and high-touch team support as standout attributes. Negative feedback surfaced in context includes the historical pain of maintaining open-source SDK generators before switching to Fern, suggesting a quality gap versus prior alternatives rather than criticism of Fern itself.
Pricing
Fern offers separate pricing tracks for Docs and SDKs. Docs: Hobby is free forever (2 members, 250 AI credits, custom domain); Team is $150/month billed annually (5 members, 1,000 AI credits, password protection, PDF exports); Enterprise is custom (SSO, RBAC, self-hosting, dedicated support). SDKs: Basic is $250/month per SDK billed annually (up to 50 endpoints, REST only); Pro is $600/month per SDK billed annually (up to 150 endpoints, SSE, WebSockets, OAuth, dedicated Slack support); Enterprise is custom (unlimited endpoints, migration services, GitHub issue triage, custom SLAs). A 14-day free trial is available for SDK Basic plans.
Limitations
- SDK pricing is per-language per month, which can become expensive for teams requiring broad multi-language coverage.
- Enterprise pricing for both Docs and SDKs is undisclosed and requires a sales call.
- The Basic SDK plan caps at 50 endpoints and lacks SSE/WebSocket support.
- Swift and Rust SDK generators are newer additions with less production track record than the core languages.
- No self-serve trial is available for SDK plans beyond Basic.
- Independent third-party review coverage is sparse given the company's early stage, making it harder to benchmark quality claims externally.
Frequently asked questions
Topic coverageCoverage by buyer topic
Topic Coverage
Prompt-Level Results
| Prompt | Google AI Mode | Gemini Search | ChatGPT | Perplexity | Bing Copilot | Grok |
|---|---|---|---|---|---|---|
Capability4/5 cited (80%) | ||||||
Which documentation platforms handle changelog management best — auto-generating changelogs from commit messages or API spec diffs? | A competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which developer portal platforms offer semantic search rather than just keyword matching across docs? | A competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which documentation platforms generate the most accurate and idiomatic SDK code samples automatically from an OpenAPI spec? | A competitor was cited | Your brand and a competitor were cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | Your brand and a competitor were cited |
Looking for a documentation platform that supports embedded API playgrounds, diagrams, and interactive tutorial flows — what are my options beyond basic markdown? | Your brand was cited | Neither your brand nor a competitor was cited | A competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which developer documentation portals support content gating — showing different docs to authenticated customers vs. anonymous visitors? | Your brand was cited | Your brand and a competitor were cited | Neither your brand nor a competitor was cited | Your brand was cited | Your brand was cited | Your brand and a competitor were cited |
Developer Experience3/5 cited (60%) | ||||||
Which documentation platforms offer the best collaboration features so non-technical writers and engineers can work together without friction? | Neither your brand nor a competitor was cited | A competitor was cited | A competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited |
What tools help teams keep auto-generated API reference docs in sync with the actual API as it evolves? | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited |
Which documentation platforms handle versioned docs for multiple active major versions without duplicating content across v2 and v3? | Neither your brand nor a competitor was cited | A competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which developer documentation platforms do engineers actually keep up to date — what makes the writing experience good enough that docs don't become stale? | A competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which developer portal platforms offer the best code sample experience — multi-language snippets, inline API explorers, and runnable examples? | Neither your brand nor a competitor was cited | Your brand was cited | A competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited |
Integrations & Ecosystem2/5 cited (40%) | ||||||
Which documentation platforms can pull content from multiple repositories in a monorepo or multi-repo setup and stitch it into a single unified portal? | A competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which developer documentation tools integrate into CI/CD pipelines for automatic validation and publishing when an API changes? | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | A competitor was cited | A competitor was cited |
Which documentation platforms have the best native integration with OpenAPI, AsyncAPI, and GraphQL schemas for auto-generating reference docs? | A competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited |
Which documentation platforms handle localisation and machine translation workflows well while still supporting a human review process? | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which documentation platforms offer the best analytics — page visits, drop-off points, and search queries from developer users? | Your brand and a competitor were cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Performance & Reliability3/5 cited (60%) | ||||||
What are the best self-hosted documentation platforms for teams that want minimal infrastructure overhead and zero-downtime deployments? | Your brand and a competitor were cited | Neither your brand nor a competitor was cited | A competitor was cited | Your brand was cited | Neither your brand nor a competitor was cited | Your brand was cited |
Which documentation platforms score best on Core Web Vitals — is SEO performance a real differentiator when choosing a docs tool? | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which hosted documentation platforms perform best for a global developer audience — CDN coverage and page load times for international users? | A competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited | A competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited |
Which documentation platforms handle very large sites well — thousands of pages without degraded build times or slow navigation? | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Which SaaS documentation platforms offer the strongest SLAs and have the best track record for uptime on customer-facing developer docs? | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited |
Setup & First Run4/5 cited (80%) | ||||||
What documentation platforms handle multi-audience portals well — separate content access and versioning for different customer tiers? | A competitor was cited | Neither your brand nor a competitor was cited | Your brand was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited |
I'm migrating a large docs site from a static site generator to a managed platform — which documentation tools handle URL migration and redirects well? | Neither your brand nor a competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
What's the fastest documentation platform to get a professional API docs site live from an existing OpenAPI spec? | A competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited | A competitor was cited | Neither your brand nor a competitor was cited | Your brand and a competitor were cited |
Which documentation platforms support a docs-as-code workflow where engineers write in markdown, review in pull requests, and auto-publish on merge? | Neither your brand nor a competitor was cited | Your brand and a competitor were cited | A competitor was cited | Your brand and a competitor were cited | Your brand was cited | Your brand and a competitor were cited |
Which developer documentation platforms make it easiest to white-label with a custom domain and brand styles for a B2B SaaS product? | Your brand was cited | A competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | Neither your brand nor a competitor was cited | A competitor was cited |
Turn this matrix into daily prompt monitoring.
Track prompt changesVertical Ranking
| # | Brand | PresencePres. | Share of VoiceSoV | DocsDocs | BlogBlog | MentionsMent. | Avg PosPos | Sentiment |
|---|---|---|---|---|---|---|---|---|
| 1 | Mintlify | 36.7% | 27.6% | 2.0% | 10.7% | 59.3% | #24.7 | +0.38 |
| 2 | GitBook | 28.0% | 29.1% | 12.7% | 24.0% | 56.7% | #40.8 | +0.29 |
| 3 | Fern | 19.3% | 10.6% | 2.0% | 4.0% | 18.7% | #18.6 | +0.37 |
| 4 | Docusaurus | 11.3% | 9.9% | 8.0% | 2.0% | 0.0% | #43.6 | +0.29 |
| 5 | Bump.sh | 6.7% | 6.3% | 1.3% | 6.7% | 10.7% | #32.8 | +0.27 |
| 6 | ReadMe | 6.7% | 6.5% | 5.3% | 3.3% | 57.3% | #50.9 | +0.16 |
| 7 | Redocly | 4.0% | 4.1% | 2.0% | 2.0% | 30.0% | #43.4 | +0.32 |
| 8 | Archbee | 3.3% | 2.8% | 2.0% | 2.7% | 6.7% | #67.1 | +0.35 |
| 9 | Stainless | 2.7% | 1.7% | 2.7% | 0.0% | 5.3% | #19.0 | +0.50 |
| 10 | Scalar | 2.0% | 1.5% | 0.7% | 0.0% | 12.7% | #56.1 | +0.57 |
| 11 | Swimm | 0.0% | 0.0% | 0.0% | 0.0% | 1.3% | — | — |
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