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description=Generate idiomatic SDKs in 9 languages with retries, pagination, idempotency, and tests. From your OpenAPI spec, published on autopilot.;

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Text of the page (random words):
fern sdks client libraries for developers and agents products resources docs beautiful customizable documentation websites sdks client libraries designed by language experts cli interact with your api from the terminal documentation learn how to use fern careers we re hiring trust center soc 2 compliant and secure get your agent readiness score customers blog pricing sign in start for free book a demo sign in book a demo sdks designed by language experts every sdk respects the idioms of the language contains strong types inlined docs and intuitive error handling migrate from payment service open editors payment gateway ts payment service src index ts payment gateway ts discriminated unions ts auto pagination ts retries ts idempotency ts multipart upload ts package json env example payment gateway ts payment gateway ts paymentgateway createpayment 1 src payment gateway ts 2 export interface paymentinput 3 amount number 4 sourceid string 5 6 7 export class paymentgateway 8 async createpayment input paymentinput 9 todo implement square payment 10 return null 11 12 problems 0 output debug console terminal ports spell checker 1 zsh ln 8 col 28 spaces 4 utf 8 lf typescript read case study we used an alternative sdk generator openapi generator for years and customers constantly complained since adopting fern customers have migrated rapidly to our new sdks and have been blown away by the quality gil feig cto making it easier to onboard agents and humans m a k i n g i t e a s i e r t o o n b o a r d a g e n t s a n d h u m a n s every sdk ships with onboarding docs by default readable for new engineers and structured for coding agents square typescript library the square typescript library provides convenient access to the square apis from typescript table of contents installation reference versioning usage request and response types exception handling file uploads pagination webhook signature verification installation bash npm i s square reference a full reference is available here versioning by default the sdk is pinned to the latest version you can override the api version per request typescript await client payments create request version 2024 05 04 usage typescript import squareclient from square const client new squareclient token your_token await client payments create sourceid ccof gajgnaza8x4ogdjn4gb amountmoney amount bigint 1000 currency usd request and response types typescript import square from square const request square revoketokenrequest clientid client_id accesstoken access_token exception handling typescript import squareerror from square try await client payments create request catch err if err instanceof squareerror console log err statuscode pagination typescript const pageableresponse await client bankaccounts list limit 1 for await const item of pageableresponse console log item webhook signature verification typescript import webhookshelper from square const isvalid webhookshelper verifysignature requestbody body signatureheader signature signaturekey process env square_webhook_signature_key notificationurl https example com webhook readme md a concise readme in the package root install command quickstart snippet in the sdk s idiomatic style links to the full reference reference oauth client oauth revoketoken params square revoketokenresponse description revokes an access token generated with the oauth flow usage typescript await client oauth revoketoken clientid client_id accesstoken access_token ️ parameters request square revoketokenrequest reference md a full markdown reference of every method parameter and return type designed to be dropped straight into a coding agent s context built for every language one spec nine sdks every generator carries the same set of ergonomic features so consumers get the same experience regardless of language 1 switch on the discriminator typescript narrows each branch 2 import squareclient from square 3 4 const square new squareclient token process env square_token 5 6 const object await square catalog object get objectid obj_42 7 8 switch object type 9 case item 10 console log item object itemdata name 11 break 12 case image 13 console log image object imagedata url 14 break 15 case discount 16 console log discount object discountdata name 17 break 18 default 19 console log other object type 20 discriminated unions first class tagged unions for polymorphic types so consumers get exhaustive narrowing auto pagination iterate offset cursor uri and path based pages with one method retries with backoff automatic retries with exponential backoff so transient failures don t surface idempotency headers safe replay headers on mutating endpoints no duplicate writes multipart form data typed builders for file uploads and multipart fields built for every language one spec nine sdks every generator carries the same set of ergonomic features so consumers get the same experience regardless of language discriminated unions first class tagged unions for polymorphic types so consumers get exhaustive narrowing auto pagination iterate offset cursor uri and path based pages with one method retries with backoff automatic retries with exponential backoff so transient failures don t surface idempotency headers safe replay headers on mutating endpoints no duplicate writes multipart form data typed builders for file uploads and multipart fields 1 switch on the discriminator typescript narrows each branch 2 import squareclient from square 3 4 const square new squareclient token process env square_token 5 6 const object await square catalog object get objectid obj_42 7 8 switch object type 9 case item 10 console log item object itemdata name 11 break 12 case image 13 console log image object imagedata url 14 break 15 case discount 16 console log discount object discountdata name 17 break 18 default 19 console log other object type 20 just run j u s t r u n fern generate f e r n g e n e r a t e fern generates and publishes client libraries so you can focus on building the api 1 import your api spec start with openapi asyncapi openrpc grpc or our simpler fern definition format select a spec openapi asyncapi openrpc grpc openapi yml 1 title public api 2 paths 3 jobs 4 post 5 summary create a new job x fern sdk group name jobs x fern sdk method name create 8 request 9 application json 10 schema 11 ref components schemas createjobrequest 12 response 13 200 14 application json 2 select languages to generate we support typescript python go java ruby c php swift rust typescript sdk public fork 548 star 2k main code fern api bot release 1 0 0 7ddf16d 2 minutes ago 877 commits github release 1 0 0 2 minutes ago src release 1 0 0 2 minutes ago tests release 1 0 0 2 minutes ago package json release 1 0 0 2 minutes ago readme md release 1 0 0 2 minutes ago 3 add custom code extend the generated client with utility functions and custom logic your changes won t be overwritten on re generation merged add helper method poll job completion 8211 changes from all commits review changes 1 class jobclient extends baseclient 2 const timeout_in_ms 10_000 3 4 public async awaitcompletion promise void 5 const poller new jobpoller this jobid 6 7 return new promise resolve reject 8 poller start resolve 4 publish packages fern semantically versions and publishes packages to each registry e g npm pypi maven your company 7 15 0 public published 24 days ago readme code beta 13 dependencies 55 dependents 83 versions typescript sdk npm v7 15 0 sdk generated by fern this library provides access to your company s api from applications written in typescript or javascript documentation documentation and api reference is available here installation npm i s your company usage import cohereclient from cohere ai install npm i your package repository github com your company type homepage github com your company type weekly downloads 71 703 version 1 0 0 license none unpacked size 3 04 mb total files 2695 issues 0 pull requests 0 last publish 24 days ago tested by default t e s t e d b y d e f a u l t every generated sdk ships with three layers of tests so you can catch regressions before they reach production unit tests cover every method in isolation so type drift and bad signatures fail before merge mock server tests replay each request against a mock server so pagination retries and errors stay honest integration tests run the sdk against a live api so end to end behavior matches what users hit built by language experts b u i l t b y l a n g u a g e e x p e r t s each sdk gives the impression of being hand written by an expert in the language type system 4 strongly typed move fast and break nothing with type safety across every method parameter and response discriminated unions first class support for discriminated unions so consumers get exhaustive type narrowing schema validation fail fast when payloads diverge from your schema both in tests and at runtime forward compatibility sdks stay fault tolerant as your api evolves so old clients keep working developer experience 7 ide support rich autocomplete and inline documentation in every major editor idiomatic method names fine tune sdk resources and method names to match the conventions of each language openapi overrides refine and augment your openapi spec without modifying the source fix gaps and improve sdk ergonomics openapi overlays compose multiple openapi overlay documents to layer changes on top of your spec without forking it autogenerated readme ship a polished readme with every sdk install instructions usage examples and links to your docs generated from your spec generated reference md every sdk ships a method by method reference md so consumers can browse the full surface area on github code snippets always accurate code examples in your docs no more hand written snippets that drift networking 4 auto pagination paginate through api responses using offset cursor or link based pagination automatically server sent events stream json data from your server to your client with typed sse support websockets send and receive messages over websockets with strongly typed payloads multipart form data sdks that handle multipart uploads with the right ergonomics for each language reliability 3 retries with backoff automatically retry failed requests with exponential backoff so transient failures don t surface idempotency built in idempotency headers protect against duplicate submissions on retried requests wire unit tests auto generated wire tests run requests against a mock server alongside unit tests for serialization and pagination both ship with every sdk auth security 2 oauth token refresh first class oauth support including automatic token refresh on expired credentials webhook signature verification verify the signature of incoming webhook requests so consumers trust what they receive releases 3 autorelease detect api changes regenerate sdks and publish to package registries all on autopilot custom code extend the generated sdk with additional methods and helpers that survive regeneration merge multiple apis combine multiple api definitions into a single cohesive sdk for your customers enterprise ready by default e n t e r p r i s e r e a d y b y d e f a u l t security deployment and partnership that scale with your api security access control gate your docs so customers see only the content relevant to them connect any saml or oidc provider and lock pages down by role team or plan email jane yourcompany com password sign in multi source docs aggregate content from multiple repos into one site with product and version switching that scales across teams without breaking ia docs example com acme server api acme ts sdk sdk acme billing billing self host run on our managed cloud or self host to meet stricter security networking and compliance requirements localization first class translated content ship docs in multiple languages as part of the rollout not as a bolt on compliance soc 2 type ii and annual pentests reports and supporting security documentation available for procurement support slas uptime sla escalation paths and a dedicated slack or teams channel with 24 7 coverage for critical incidents delight your developers with beautiful docs idiomatic sdks an agent first cli subscribe all systems operational soc 2 type ii also of interest how 2 designers and ai rebuilt fern s marketing site revamping our website introducing fern replay view as markdown documentation getting started openapi compatibility docs sdks cli resources blog careers customers support pricing company brand kit github privacy policy terms of service 2026 fern a postman company located in brooklyn new york dev