Lemmy — how to connect

Posts text (and optional link) posts to a Lemmy community on any federated instance. No app setup needed — paste your instance URL, username, and password when you add the account; a target community is required per account.

Lemmy has no app-registration or API-key flow — you connect by pasting your existing account credentials for a specific instance, and the tool logs in and stores the resulting session token.

Before you start

An existing account on the target Lemmy instance (e.g. lemmy.world, lemmy.ml) — sign-up happens on the instance itself, not through this tool
The account must be fully activated: instance-required email verified and, if the instance gates new sign-ups, the registration application approved by an instance admin (login otherwise silently returns no session)
If two-factor authentication (TOTP) is enabled on the account, a current 6-digit code ready to paste at connect time — codes can't be supplied later at publish time
The exact name (or name@instance for cross-instance targets) of a community you're already allowed to post in, since every post requires a resolvable target community

Step by step

1
Pick or confirm your home instance
Have the full URL of the Lemmy instance where your account lives (e.g. https://lemmy.world or https://lemmy.ml) — this is what you'll paste as the Instance URL.
Open
2
Make sure you have an active Lemmy account on that instance
Sign up or log in at the instance's own site first; some instances require email verification or admin approval before login succeeds via the API.
Open
3
Enter your instance URL
In the connect form, paste the instance URL exactly as above (e.g. https://lemmy.world) into the Instance URL field.
4
Enter your username or email and password
Use the same login you use on the instance's website — the tool calls the instance's own /api/v3/user/login endpoint with these values.
5
Add your 2FA code if TOTP is enabled on the account
If you've turned on two-factor auth in your Lemmy account settings, generate a fresh code from your authenticator app and paste it into the 2FA code field at connect time (it's a one-time value, not stored).
6
Enter the default community you'll post to
Paste the target community name, either short form like technology or fully qualified like technology@lemmy.world, into the Default community field — a community is required for every post.

Paste when you connect

Instance URL
Full URL of the instance your account lives on (e.g. https://lemmy.world). No app registration exists — you log in with your normal account.
Username or email
The same login you use on the instance's website.
Passwordsecret
Your account password. Account must be email-verified (and approved, if the instance gates sign-ups) or login returns no session.
2FA code (if enabled)
Only if TOTP is on. It's one-time and not stored, so 2FA accounts need a fresh code each reconnect.
Default community
Required — every post needs a target. Use the URL slug (technology), or name@instance for a community on another instance.

Good to know

No developer app, client ID, or API key exists in Lemmy — connecting is just a normal account login, so treat the password as sensitive as the account itself.
If login returns no JWT, the most common causes are: 2FA required but no/incorrect code was supplied, email verification pending, or the instance requires admin approval for new accounts.
Lemmy JWTs generally do not expire and there's no refresh endpoint, so a 401 later means the account must be reconnected from scratch, not silently refreshed.
TOTP codes are only usable at the moment of connecting — there's no way to store a TOTP secret for later automated re-logins, so 2FA accounts may need periodic reconnects.
The community field is per-account and required: posts fail if no meta.community or meta.communityId is resolvable on the home instance.
join-lemmy.org's published API docs largely describe the lemmy-js-client behavior rather than a formal language-neutral spec, but the /api/v3/user/login, /api/v3/site, and /api/v3/post endpoints this adapter uses are stable/current as of 2026.

Troubleshooting

Connect fails with "Lemmy login returned no jwt" even though the username/password are correct: The instance is withholding the session token because the account isn't fully cleared to log in yet — usually pending email verification or a pending/rejected registration application. Verify the email and/or wait for an admin to approve the application on that instance, then reconnect.
Connect fails or hangs when 2FA is enabled: Paste a fresh TOTP code into the 2FA field at connect time (the field the adapter exposes). There's no way to add a code later — if the login already failed, generate a new code (they rotate every 30s) and retry immediately, since Lemmy has no separate refresh flow for 2FA.
Publish fails with "community not found on <instance>": The community name is wrong, misspelled, or exists only on a different instance. Use the exact slug shown in the community's Lemmy URL, and for a remote community qualify it as name@instance.tld (e.g. technology@lemmy.world) so it resolves via federation.
Publish suddenly starts failing with 401 after previously working: Lemmy JWTs don't expire on a timer, but they are invalidated if the password is changed, 2FA is toggled, or an admin/security action resets sessions. There is no token refresh — remove and reconnect the account with the current password (and current 2FA code if applicable).
Publish fails with a rate-limit error during bursts of posts: Lemmy enforces per-account/IP rate limits on posting (instance-configurable, tighter on smaller/community instances). Space out publishes to that account and retry after a short delay rather than immediately resubmitting.

Lemmy developer docs

Before you start

An existing account on the target Lemmy instance (e.g. lemmy.world, lemmy.ml) — sign-up happens on the instance itself, not through this tool

The account must be fully activated: instance-required email verified and, if the instance gates new sign-ups, the registration application approved by an instance admin (login otherwise silently returns no session)

If two-factor authentication (TOTP) is enabled on the account, a current 6-digit code ready to paste at connect time — codes can't be supplied later at publish time

The exact name (or name@instance for cross-instance targets) of a community you're already allowed to post in, since every post requires a resolvable target community

Step by step

Pick or confirm your home instance

Have the full URL of the Lemmy instance where your account lives (e.g. https://lemmy.world or https://lemmy.ml) — this is what you'll paste as the Instance URL.

Open

Make sure you have an active Lemmy account on that instance

Sign up or log in at the instance's own site first; some instances require email verification or admin approval before login succeeds via the API.

Open

Enter your instance URL

In the connect form, paste the instance URL exactly as above (e.g. https://lemmy.world) into the Instance URL field.

Enter your username or email and password

Use the same login you use on the instance's website — the tool calls the instance's own /api/v3/user/login endpoint with these values.

Add your 2FA code if TOTP is enabled on the account

If you've turned on two-factor auth in your Lemmy account settings, generate a fresh code from your authenticator app and paste it into the 2FA code field at connect time (it's a one-time value, not stored).

Enter the default community you'll post to

Paste the target community name, either short form like technology or fully qualified like technology@lemmy.world, into the Default community field — a community is required for every post.

Paste when you connect

Instance URL

Full URL of the instance your account lives on (e.g. https://lemmy.world). No app registration exists — you log in with your normal account.

Username or email

The same login you use on the instance's website.

Passwordsecret

Your account password. Account must be email-verified (and approved, if the instance gates sign-ups) or login returns no session.

2FA code (if enabled)

Only if TOTP is on. It's one-time and not stored, so 2FA accounts need a fresh code each reconnect.

Default community

Required — every post needs a target. Use the URL slug (technology), or name@instance for a community on another instance.

Good to know

No developer app, client ID, or API key exists in Lemmy — connecting is just a normal account login, so treat the password as sensitive as the account itself.

If login returns no JWT, the most common causes are: 2FA required but no/incorrect code was supplied, email verification pending, or the instance requires admin approval for new accounts.

Lemmy JWTs generally do not expire and there's no refresh endpoint, so a 401 later means the account must be reconnected from scratch, not silently refreshed.

TOTP codes are only usable at the moment of connecting — there's no way to store a TOTP secret for later automated re-logins, so 2FA accounts may need periodic reconnects.

The community field is per-account and required: posts fail if no meta.community or meta.communityId is resolvable on the home instance.

join-lemmy.org's published API docs largely describe the lemmy-js-client behavior rather than a formal language-neutral spec, but the /api/v3/user/login, /api/v3/site, and /api/v3/post endpoints this adapter uses are stable/current as of 2026.

Troubleshooting

Connect fails with "Lemmy login returned no jwt" even though the username/password are correct

The instance is withholding the session token because the account isn't fully cleared to log in yet — usually pending email verification or a pending/rejected registration application. Verify the email and/or wait for an admin to approve the application on that instance, then reconnect.

Connect fails or hangs when 2FA is enabled

Paste a fresh TOTP code into the 2FA field at connect time (the field the adapter exposes). There's no way to add a code later — if the login already failed, generate a new code (they rotate every 30s) and retry immediately, since Lemmy has no separate refresh flow for 2FA.

Publish fails with "community not found on <instance>"

The community name is wrong, misspelled, or exists only on a different instance. Use the exact slug shown in the community's Lemmy URL, and for a remote community qualify it as name@instance.tld (e.g. technology@lemmy.world) so it resolves via federation.

Publish suddenly starts failing with 401 after previously working

Lemmy JWTs don't expire on a timer, but they are invalidated if the password is changed, 2FA is toggled, or an admin/security action resets sessions. There is no token refresh — remove and reconnect the account with the current password (and current 2FA code if applicable).

Publish fails with a rate-limit error during bursts of posts

Lemmy enforces per-account/IP rate limits on posting (instance-configurable, tighter on smaller/community instances). Space out publishes to that account and retry after a short delay rather than immediately resubmitting.