encore-go-api

Encore Go API Endpoints

Instructions

When creating API endpoints with Encore Go, follow these patterns:

1. Basic API Endpoint

Use the //encore:api annotation above your function:

package user

import "context"

type GetUserParams struct {
    ID string
}

type User struct {
    ID    string `json:"id"`
    Email string `json:"email"`
    Name  string `json:"name"`
}

//encore:api public method=GET path=/users/:id
func GetUser(ctx context.Context, params *GetUserParams) (*User, error) {
    // Implementation
    return &User{ID: params.ID, Email: "user@example.com", Name: "John"}, nil
}

2. POST with Request Body

type CreateUserParams struct {
    Email string `json:"email"`
    Name  string `json:"name"`
}

//encore:api public method=POST path=/users
func CreateUser(ctx context.Context, params *CreateUserParams) (*User, error) {
    // Implementation
    return &User{ID: "new-id", Email: params.Email, Name: params.Name}, nil
}

API Annotation Options

Option	Values	Description
public	-	Accessible from outside
private	-	Only callable from other services
auth	-	Requires authentication
method	GET, POST, PUT, PATCH, DELETE	HTTP method
path	string	URL path with :param for path params
sensitive	-	Redacts request/response payloads from traces

Examples

//encore:api public method=GET path=/health
//encore:api private method=POST path=/internal/process
//encore:api auth method=GET path=/profile
//encore:api public sensitive method=POST path=/auth/login

Sensitive Data

Mark sensitive fields to redact them from tracing logs:

type LoginParams struct {
    Email    string `json:"email"`
    Password string `json:"password" encore:"sensitive"`
}

Or mark the entire endpoint as sensitive in the annotation:

//encore:api public sensitive method=POST path=/auth/login
func Login(ctx context.Context, params *LoginParams) (*TokenResponse, error) {
    // Request and response will be redacted from traces
}

Custom HTTP Status Codes

Return custom HTTP status codes using the encore:"httpstatus" tag:

type CreateResponse struct {
    ID     string `json:"id"`
    Status int    `encore:"httpstatus"`
}

//encore:api public method=POST path=/items
func CreateItem(ctx context.Context, params *CreateParams) (*CreateResponse, error) {
    item := createItem(params)
    return &CreateResponse{
        ID:     item.ID,
        Status: 201,  // Returns HTTP 201 Created
    }, nil
}

Request Parameter Sources

Path Parameters

// Path: /users/:id
type GetUserParams struct {
    ID string  // Automatically mapped from :id
}

Query Parameters

// Path: /users
type ListUsersParams struct {
    Limit  int `query:"limit"`
    Offset int `query:"offset"`
}

//encore:api public method=GET path=/users
func ListUsers(ctx context.Context, params *ListUsersParams) (*ListResponse, error) {
    // params.Limit and params.Offset come from query string
}

Headers

type WebhookParams struct {
    Signature string `header:"X-Webhook-Signature"`
    Payload   string `json:"payload"`
}

Cookies

import "net/http"

type AuthParams struct {
    SessionCookie *http.Cookie `cookie:"session"`
    CSRFToken     string       `header:"X-CSRF-Token"`
}

//encore:api auth method=POST path=/logout
func Logout(ctx context.Context, params *AuthParams) error {
    // Access params.SessionCookie.Value
    return nil
}

Response Types

Standard Response

type Response struct {
    Message string `json:"message"`
}

//encore:api public method=GET path=/hello
func Hello(ctx context.Context) (*Response, error) {
    return &Response{Message: "Hello, World!"}, nil
}

No Response Body

//encore:api public method=DELETE path=/users/:id
func DeleteUser(ctx context.Context, params *DeleteParams) error {
    // Return only error (no response body on success)
    return nil
}

No Request Parameters

//encore:api public method=GET path=/health
func Health(ctx context.Context) (*HealthResponse, error) {
    return &HealthResponse{Status: "ok"}, nil
}

Error Handling

Use errs package for proper HTTP error responses:

import "encore.dev/beta/errs"

//encore:api public method=GET path=/users/:id
func GetUser(ctx context.Context, params *GetUserParams) (*User, error) {
    user, err := findUser(params.ID)
    if err != nil {
        return nil, err
    }
    if user == nil {
        return nil, &errs.Error{
            Code:    errs.NotFound,
            Message: "user not found",
        }
    }
    return user, nil
}

Common Error Codes

Code	HTTP Status	Usage
errs.NotFound	404	Resource doesn't exist
errs.InvalidArgument	400	Bad input
errs.Unauthenticated	401	Missing/invalid auth
errs.PermissionDenied	403	Not allowed
errs.AlreadyExists	409	Duplicate resource

Guidelines

• Use //encore:api annotation above the function
• Request params must be a pointer to a struct or omitted
• Response must be a pointer to a struct (or omit for no body)
• Always return error as the last return value
• Use struct tags for JSON field names, query params, and headers
• Path parameters are automatically mapped to struct fields by name