Infor LN REST API: documentation, administration and a first call
infor ln rest api documentation
Also searched as
- infor ln rest api administration guide
- infor ion api gateway ln
- infor ln rest api token ionapi
Short answer
LN REST access goes through the Infor ION API gateway. You register an authorized app in ION API, download its .ionapi credentials file, obtain an OAuth 2.0 token and call the LN API endpoints with the bearer token. Official reference material is on the Infor documentation site and the ION API documentation inside your Infor OS portal.
Applies to: Infor LN 10.x with Infor OS ION API, on-prem or cloud. Endpoint paths depend on the API and version.
Make a first call
- 1In Infor OS, open ION API and confirm the LN API suite is available for your tenant.
- 2Create an Authorized App of type Backend Service, with a service account, and download the .ionapi file.
- 3Read the file: it contains client id (ci), client secret (cs), the token URL parts (pu and ot), the service account keys (saak and sask) and the tenant (ti).
- 4Request a token with the password grant, using saak and sask as username and password and ci and cs as client credentials.
- 5Call the LN API endpoint shown in the ION API documentation for your service, with the header Authorization: Bearer <token>.
- 6Start with a read (GET) of a small entity and check the response before attempting any write.
Where the documentation is
Three sources matter. The Infor documentation site has the ION API guide and the LN-specific API guides for your release. The ION API application inside Infor OS lists the APIs available to your tenant, with a try-it-out view. The Infor support portal holds version-specific notes and known issues.
Because paths and versions differ between releases, always take the endpoint from your own ION API listing, not from a blog post.
Administration
Administer access in ION API: authorized apps, service accounts, scopes and which security roles the service account maps to in LN. The service account needs an LN user with the right authorizations, otherwise calls authenticate but fail with authorization errors from LN.
Rotate secrets as you would any credential, and keep the .ionapi file out of source control.
POST <pu><ot>
Content-Type: application/x-www-form-urlencoded
grant_type=password&username=<saak>&password=<sask>&client_id=<ci>&client_secret=<cs>
Choosing REST, BODs or direct database reads
REST suits request-response integrations and AI tools. BODs suit event-driven exchange. Direct database reads are fastest for analytics but bypass LN business logic and are not appropriate for writes.
For AI assistants, a common pattern is read-only SQL or API access for retrieval, and a REST call behind human approval for any write.
Try it here, free
Infor LN Support Ticket Template
Write an LN incident report that support can act on the first time: environment, session, steps, error and business impact.
Common pitfalls
- !Using endpoints copied from an old tutorial.
- !Service account with no LN authorizations.
- !Committing the .ionapi file to a repository.
- !Testing writes in production first.
- !Ignoring token expiry in long-running jobs.
How an ERP-grounded AI assistant handles this
Netray builds agents that call ION API with a least-privilege service account, show the request before it runs, and hold writes for approval. The model runs on your own GPUs, so credentials and payloads never reach a public AI service.
Frequently asked questions
Where is the Infor LN REST API documentation?
Use the Infor documentation site for your LN release and the ION API listing in your Infor OS portal. The latter shows the exact endpoints enabled for your tenant.
What is an .ionapi file?
A JSON credentials file generated for an authorized app. It holds client and service account details needed to request OAuth tokens.
Can I call LN REST without ION API?
In standard deployments the supported route is through ION API. Confirm with Infor for your version if you need another route.
Why do I get a 401 or 403?
401 usually means a bad or expired token. 403 often means the service account lacks LN authorization for that entity.
Related
Infor LN integration document types and integration rules with ION
In LN, an integration document type ties an LN business object to a BOD noun and direction so ION can send or receive it. Rules and mappings then decide which LN data populates the BOD, which events trigger publication and how incoming BODs are converted into LN transactions. Set up the document type first, then the mapping, then test in ION Desk.
How-toHow to publish a BOD from Infor LN to Infor ION
Publishing a Business Object Document from Infor LN means flagging the relevant table or session for BOD publish, confirming LN's connection point to Infor ION is active, and building the document flow in ION Desk so changes like a new sales order are broadcast as a standard OAGIS-style XML message that other applications can subscribe to.
AdvancedHow to extend business logic in Infor LN with DAL2
DAL2 lets you add custom validation, defaulting and calculation logic to Infor LN Enterprise Edition tables by writing a Java business logic handler class and registering it against a table event, without editing the standard DAL. Because the logic sits in your own package rather than inside Infor's base code, it survives upgrades that would otherwise overwrite a direct DAL change.
Error fixInfor LN Not Authorized to Run This Session: How to Fix It
Infor LN refuses to open a session with a not authorized message when the logged-in user's assigned role does not include that session, or when the session is blocked for the company they are logged into. Grant the session through Common > Authorization Management > Roles, or check the user's role and company context, and the session opens on retry. In most cases this is a permissions configuration issue, not a bug.
Error fixInfor LN bshell Process Stuck at 100% CPU: How to Diagnose and Fix It
A bshell process pinned at 100% CPU on the Infor LN application server almost always means one session is stuck in a 4GL loop, scanning an unindexed table, or waiting on a database lock. End the session from the Sessions Monitor first, then kill the OS process only if that fails, and check for a blocking database transaction before assuming it is a bug.
Error fixInfor LN DAL Out of Sync After a Custom Field: Cause and Fix
Infor LN throws a DAL, or table, out of sync error, or simply drops a new custom field silently, when a table's dictionary definition is changed but the generated DAL and dependent forms are not regenerated afterward. Running the standard sequence, table compile, DAL generation, then session/form compile, in Tools > Development after every dictionary change resolves it. Skipping any one of the three steps is what causes the mismatch.
AI for ERPAI for Infor LN: Sessions, BODs, and Engineer-to-Order Work
Add grounded AI to Infor LN 10.x or CloudSuite: natural-language answers over sessions and BODs, agents for project and engineer-to-order work, on-prem options.
AI for ERPAI for Legacy Baan IV/V: Capture the Knowledge Before It Walks Out the Door
Use AI to capture knowledge from ageing Baan IV/V systems, document undocumented customisations, and de-risk a future migration to LN or CloudSuite.
Stuck on Infor LN?
Talk to engineers who work inside Infor LN every week, and who build private AI that answers these questions from your own ERP data.
Keep exploring
Free tools
- Infor LN Support Ticket TemplateWrite an LN incident report that support can act on the first time: environment, session, steps, error and business impact.
- Infor LN and Baan Terminology ReferenceA searchable glossary of Baan and Infor LN concepts for people joining a team or reading old documentation.
- Infor LN User Access Review ChecklistA practical checklist for periodic review of who can do what in Infor LN, covering roles, privileged access and segregation of duties.
ERP fixes and how-tos
- Infor LN Document Central: Attachments and Document ManagementWhat Document Central and Infor Document Management do for Infor LN, how attachments are stored and configured, and what an admin should check first.
- Infor LN and M3 BOD Documentation: Definitions, Mapping and Tracing in IONWhere to find BOD definitions for Infor LN and M3, how outbound BOD mapping works, what the M3 BOD processor does, and how to trace a BOD through ION.
- Infor LN integration document types and integration rules with IONHow integration document types and rules work in Infor LN with ION and BODs: what they define, how mapping is set up, and where to debug.
Runs with your ERP
- XEDI EDI Integration with Infor LN (ION BODs)How XEDI translates X12 and EDIFACT into Infor BODs routed through ION for Infor LN, plus SyteLine and M3. Setup steps, data flows, pitfalls and FAQ.
- Vergo AP Automation and Infor LNHow Vergo captures, codes and routes invoices and posts approved bills into Infor LN using the LN REST API, with setup, pitfalls, alternatives and AI uses.
- SIGMA MES and Infor LNSIGMA MES from a certified Infor LN partner in Germany: how it connects to Infor LN, Infor OS/ION and web services, setup, pitfalls, alternatives and AI uses.
Guides
- Infor LN ION API Integration GuideInfor ION API guide for LN: when to use the ION API gateway, BOD messaging or file-based exchange, how OAuth 2.0 access works, and how to secure calls.
- Infor LN Domain Administration GuideAdminister Infor LN domains effectively. Domain architecture, user management, environment configuration, and system maintenance best practices.
- Infor LN + ION Workflows: Proven Automation PatternsInfor LN and ION workflow automation patterns: BODs, ION Desk monitors, approval workflows, and API integration recipes that remove manual ERP busywork.
AI on your ERP
- AI for Infor LN: Sessions, BODs, and Engineer-to-Order WorkAdd grounded AI to Infor LN 10.x or CloudSuite: natural-language answers over sessions and BODs, agents for project and engineer-to-order work, on-prem options.
- AI Agents Over Infor ION API, BODs, and the Infor Data LakeBuild AI agents on Infor ION API Gateway, BODs, and Data Lake, alongside or instead of Infor's own GenAI features, with your choice of model and hosting.
Integrations
- How to add AI agents to Infor LNHow to add AI agents to Infor LN: a tool layer over ION API and BODs, read-only reporting first, approval before writes, and fully on-prem model hosting.
- How to build an MCP server for Infor LNHow to build a Model Context Protocol server for Infor LN: which read-only tools to expose, auth through ION API, stdio versus HTTP, permission scoping and audit.