Affiliate disclosure: some links in my articles are affiliate links, which means I may earn a commission if you buy through one, at no extra cost to you. I should say plainly that as of 4 September 2026 I have four approved affiliate partnerships. One is JapanesePod101, which appears on this page. Two are knife retailers and are unrelated to everything here. The fourth is The Japan Shop, a bookshop approved on 4 September 2026 which does sell books on casual and slang Japanese, so I am naming it rather than calling it unrelated. There is no link to it on this page. Other pages here do carry links to that shop, the largest being in my guide to starting to read Japanese, and my affiliate disclosure page keeps the full list current. I have placed no tracked links on this page, so as of today it earns me nothing whatsoever. It is also worth knowing in advance that the product I rate highest on this page has no cash affiliate program in existence, and the two products I mark down hardest are both products that would pay me. I have flagged which is which next to every single one.
I want to answer the question you searched for, and then explain why the answer is not the one you need.
If you want an app that will actually put casual Japanese in front of you, the short version is: JapanesePod101 has a twenty-five lesson series built entirely around informal speech, Bunpro is the only product I found that makes you type the casual form yourself, and Pimsleur and Rosetta Stone will leave you speaking polite Japanese and nothing else. That is the ranking. You can act on it.
Now here is the problem with it.
Every product on this page teaches you the forms. Several of them teach the forms well. Not one of them teaches you the thing that actually determines whether you sound like a person: deciding which form to use, in a room, about a specific human being, in the second before you open your mouth. They will hand you both registers and leave the choice entirely to you, which sounds generous and is in fact the whole difficulty relocated onto the learner.
I am going to explain why that gap exists, why it is genuinely hard to close, and what to do about it. But I have to start with an admission about myself.
The thing I should admit first
I have never chosen a politeness level in my life.
That sounds like a boast and it is the opposite. I am a native speaker, I live in Tokyo, and I switch registers something like forty times a day. I speak one way to my landlord and another way to my oldest friend, and the switch is total: verb endings, sentence particles, how much of the sentence I bother to finish. It happens correctly every time and I have never once experienced it as a decision.
It is chosen before I speak. By the time a sentence is forming, the register is already welded to it, in the same way you do not choose whether to say hi or good morning, sir to someone. You know who they are and the sentence arrives already dressed.
This is why asking a Japanese friend for help with register goes so badly. They will tell you です／ます is polite and plain form is casual, which you already know, and then they will tell you to use polite form with people older than you, which is true and nowhere near enough. They are not being lazy. They are reporting the one rule they have conscious access to, out of a system they run continuously and cannot see. I wrote a whole article about the same phenomenon happening with pitch accent, where native speakers produce a pattern flawlessly and cannot tell you what it is. Register is the same shape of problem, with much higher stakes when you get it wrong.
So my usefulness here is narrow and specific. I cannot tell you how to learn this. I never did. What I can do is tell you when a product’s model of Japanese politeness is wrong, because I am the thing it is modelling.
Why the polite-versus-casual axis is the wrong picture
Almost every learning product presents register as a slider. Casual on the left, polite on the right, formal keigo somewhere off the right-hand edge, and your job is to pick the correct position based on how much respect the situation calls for. Keigo, off that right-hand edge, now has an article of its own.
That picture is wrong in a way that will actively mislead you, and here is the cleanest proof.
Suppose my boss walks past. I speak to him in polite form, obviously. Now suppose I am on the phone with a client at another company, and my boss’s name comes up. I now refer to my own boss without any honorific language at all. I strip it. I use a plain form about the man I was deferring to ninety seconds earlier, and using polite language about him at that moment would be a real mistake, the kind that makes a client quietly downgrade their opinion of the company.
Nothing about my respect for my boss changed in those ninety seconds. What changed is which side of a line he and I were standing on. Japanese politeness is not primarily a scale of how much respect is owed. It is a running calculation of who is inside your group and who is outside it, and the inside-outside boundary moves depending on who you are talking to. Two people can be inside relative to a stranger and outside relative to each other, at the same time, and the language expects you to track it.
A slider cannot represent that. You cannot express “my boss, who outranks me, but who is on my side of this particular conversation” as a position between casual and polite. And once you notice that the model is wrong, you notice that the products built on it are teaching you to answer a question the language does not ask.
There is a second thing the slider hides. In Japanese there is no neutral setting. You cannot decline to take a position. English lets you speak to a new colleague without committing to a stance on your relative status; Japanese does not, because the commitment is inside the verb ending, and every sentence has a verb ending. Whichever way you go, you have said something about the two of you. Silence is the only abstention, and you cannot hold a conversation with it.
The asymmetry nobody warns you about
Here is the practical piece, and I think it is the single most useful paragraph on this page.
The two ways of getting register wrong are not equally bad, and they are not even close.
Being too polite makes you sound distant. A Japanese person on the receiving end registers it as slightly stiff, slightly formal, possibly a little cold, and then almost always attributes it to you being foreign and moves on. It costs you warmth. It does not cost you the relationship. I have had entire friendships start with somebody being too polite to me for a month.
Being too casual is different in kind. Plain form with someone who has not earned it does not read as friendly, it reads as a claim about the two of you that you were not entitled to make. It lands somewhere near presumptuous, and the specific damage is that it is very hard to walk back, because the correction would require your listener to say out loud that you are not as close as you assumed. Almost nobody will do that. They will absorb it, adjust their opinion, and be perfectly pleasant to you forever.
Which brings me to the reason every course you have ever seen defaults to polite form: it is the correct strategic default, and I want to defend it before I criticise anyone. If a product can only teach you one register, polite is the right one, because the failure mode is survivable. The teaching materials are not being cowardly. They are being sensible.
The problem is what happens next. The sensible default becomes the only thing you have ever produced, and eight months later you are the learner who cannot come down. You have friends your own age who have told you twice that you do not need to be so formal, and you keep doing it, because polite form is the only Japanese your mouth has ever made. The safe choice, held too long, becomes its own kind of wrong, and no product I looked at has any mechanism for noticing that this has happened to you.
And nobody will tell you. This is the part learners consistently underestimate. If your register is off, the people around you will not correct it, partly because correcting it means commenting on the relationship, and partly because your Japanese is otherwise good and they do not want to discourage you. You will get a warm, slightly formal, permanently held-at-distance version of every relationship, and no feedback explaining it.
How I judged these
Three questions, in this order.
1. Does it teach the forms at all?
The bar for a pass here is low and some products still fail it. Does the material contain plain form, casual sentence endings, dropped particles, and the contracted speech people actually use, or does it park in です／ます for the entire course? A product that never shows you casual Japanese has not taught you a formal style, it has taught you a partial language.
2. Does it make you produce the right one, or does it label it for you?
This is where everything separated, and it is the criterion I want you to carry away from this article.
There is a very large difference between these two exercises:
Put this into the casual form: 食べます
You are talking to a coworker you met last week who is five years older than you. Say that you already ate.
The first is a conjugation drill. It is useful, and it is not the skill. The second is the actual task Japanese sets you every time you speak, and I could not find a single product in this comparison that asks it. Every register exercise I found tells you which register to produce before asking you to produce it.
3. Does it explain when, not just what?
Does the product ever get specific about the social conditions? Age gap, workplace hierarchy, how long you have known someone, who else is in the room, whether you are speaking about somebody or to them. Or does it stop at the level of use polite form with strangers and casual form with friends, which is true and which will not get you through a single real Tuesday.
The comparison
Can it pay me? means the product runs an affiliate programme I could earn a commission from if you buy through my link. It is not a claim that it is paying me. I now hold four approved partnerships, one of them JapanesePod101, but there are no tracked links on this page, so nothing here pays me anything yet. I would rather you saw that next to the ratings than at the bottom of the page.
| Product | Shows you casual Japanese? | Makes you produce it? | Explains when to switch? | Can it pay me? |
|---|---|---|---|---|
| Bunpro | Yes, and it labels the register on the grammar point itself | Yes. You type the form. The only one here that does | Partly. Notes on each point, no situational practice | No — points, not cash |
| JapanesePod101 | Yes. A twenty-five lesson series built entirely on informal speech | Weak. Listening, not production | Best here. Register is discussed as a topic, repeatedly | Yes |
| Rocket Japanese | Yes. Formal and informal presented side by side | Yes, through recorded full-sentence output | Thin. It shows both and stops short of the conditions | Yes — I am not in it |
| Anki | Entirely up to your deck | Depends on your deck | No. It has no opinions about anything | No — free and open source |
| WaniKani | Not applicable. It does not teach grammar | No, and it is not pretending to | No, and it never claimed to | No — no affiliate program exists |
| Pimsleur Japanese | Barely. Level 1 is polite throughout | Yes, constantly, in one register | No | Yes |
| Rosetta Stone | No meaningful treatment | Shallow | No | Yes, and I still say skip it |
What I actually checked, and what I did not
That table is worth exactly as much as the checking behind it, so here is the checking.
JapanesePod101. I went to the lesson library and confirmed the informal series exists rather than taking a review’s word for it. Newbie Season 5 is twenty-five lessons following one learner and his cousin’s family, and the series description states outright that it is about informal Japanese. Two lesson titles in it are Being Polite Is Not Just a Formality in Japanese and Show Some Respect for Your Japanese Elders, which tells you the series is not simply teaching casual forms but treating the choice between registers as its subject. There is separately an absolute beginner video lesson introducing informal verbs, and a beginner-season lesson explicitly comparing formal and informal Japanese. This is the most register-aware catalogue in the comparison and it is not close.
Bunpro. I opened the grammar point page for だ and read what it actually says. It states that だ is casual and used in plain speech while です is polite, and that it is a casual structure which you will not see in polite sentences. So the register information is attached to the grammar point rather than mentioned once in an introductory unit and abandoned, which is the right design. In reviews Bunpro is where the register is specified in the answer field, so you supply the correct form. That makes it the only product here that gets a register into your fingers instead of your ears. It also means the register is given to you, not chosen by you, which is my criticism of the entire category and not of Bunpro specifically.
Rocket Japanese. I read one of their politeness lessons directly. It says it will show you the difference between formal and informal expressions so you use the right tone for the situation, and it does exactly that, presenting a formal thank-you next to a casual one. What it does not do is explain which situation is which. The phrases are correct and the social conditions that would let you choose between them are absent, which is a fair summary of most teaching material on this topic.
What I did not test. Pimsleur and Rosetta Stone both put their trials behind a credit card that renews automatically, and I did not give a card to either. My read on those two comes from their published method and from consistent reporting across multiple independent reviews, not from use. For Pimsleur the reporting is specific and consistent: the first level is polite throughout, and the course leans formal across all five levels. For Rosetta Stone the criticism across reviewers is that it uses polite forms almost exclusively and does not teach when or why to switch. Both of those match what their methods would predict, and I will argue the method point happily, but I am telling you it is an argument rather than a report.
What nobody could check for you. Whether a product’s register teaching survives contact with an actual conversation. It is the only test that matters and no reviewer can run it on your behalf. The nearest thing to it, and the one I would run first, is whether you can hold up the listener’s half of a Japanese conversation.
The products, one by one
Bunpro — the only one that puts a register in your fingers
Grammar by spaced repetition, five dollars a month or a one-time purchase, and the least fashionable interface here. It wins this category on a technicality that turns out not to be a technicality at all: it is the only product that makes you type the form yourself, with the register specified, over and over, until the plain form is something you produce rather than something you recognise.
That matters more than it sounds. The learners I meet who are stuck in polite form are not stuck because they do not know plain form. They know it perfectly. They have simply never produced it under any pressure, so it is not available at speed. Bunpro is the only thing here attacking that directly.
What it will not do is put you in a situation and make you choose. The blank tells you which register it wants. Can it pay me? No — Bunpro offers points rather than cash, so my top recommendation on this page cannot pay me anything.
JapanesePod101 — the best explanation of when, wrapped in a lot of other things
If your problem is understanding the system rather than drilling it, this is the strongest catalogue in the comparison, and the informal series is a genuine asset rather than a marketing claim. Twenty-five lessons that treat informality as a subject, plus scattered lessons across other seasons that come back to the formal-informal boundary, means you can actually study register as a topic instead of inferring it.
The weakness is the one I found when I reviewed the whole category for adult learners: the library is enormous and unpruned, and some lessons drill sentences attached to situations you will never be in. I found one there that teaches a form which only ever travels downward, from a parent to a child, with no warning attached. Use it by search, not in order. Can it pay me? Yes.
Rocket Japanese — shows you both, tells you neither
The most complete single course here, and its register treatment is real but shallow. You will see formal and informal side by side and hear both spoken well, and the voice recording exercise means you produce full sentences out loud, which is more than most of this list can say.
What is missing is the conditions. Presenting a formal and a casual thank-you next to each other teaches you that Japanese has two thank-yous. It does not teach you which one to use on the colleague who helped you move apartments last weekend. Can it pay me? Yes — I am not in that programme.
Anki — a mirror, not a teacher
Free, open source, and exactly as good as whatever you put into it. There is a real use here that nobody mentions: if you are stuck in polite form, build a deck of your own sentences in both registers and drill the plain versions specifically. Anki will do that for you and nothing else on this list will.
It has no register knowledge of its own. It is a tool for practising decisions you have already made. Can it pay me? No.
WaniKani — not in this race, and honest about it
Kanji and vocabulary, nothing else, no grammar and therefore no register. I include it because it is the product I recommend most often overall and I do not want its absence here read as a mark against it. It is not failing at register teaching. It declined to enter the category. Can it pay me? No — no affiliate program exists.
Pimsleur Japanese — the best speaking practice here, in one register
I want to be fair to this one, because I rate its method highly and it is the only product on this list that reliably forces spoken output. If your problem is that you freeze when it is your turn to talk, this remains the most effective thing available.
But the reporting on its register coverage is consistent across independent reviews, and it matches what the method implies: the first level is polite throughout, and the whole course leans formal. You will finish it with genuine spoken fluency in exactly one voice, which is a real outcome and a real limitation. Note that this is a product that would pay me, and it is going into the second half of the ranking on this specific criterion. Can it pay me? Yes.
Rosetta Stone — the one I would skip, again
Immersion without explanation, applied to a language which encodes your relationship to the listener inside the verb. Reviewers consistently report it uses polite forms almost exclusively and does not teach the switch. That is exactly what you would predict from a method that avoids explaining grammar in your native language, because the inside-outside logic I described earlier cannot be inferred from pictures. It has to be told to you.
It would pay me a commission. I have now recommended against it in three consecutive articles. Can it pay me? Yes, and no.
So what should you actually do
If you are a beginner, ignore this entire article for now and stay in polite form. I mean it. The asymmetry above is the reason: too polite is survivable and too casual is not, and you do not yet have the read on people to make the call. Come back at the point where you are having real conversations and somebody has told you to relax.
If you are stuck in polite form, which is the most common version of this problem, your issue is production and not knowledge. Bunpro for the plain forms until they arrive without effort, plus an Anki deck of your own sentences in both registers. Do not add another course. You do not need more input.
If you do not understand the system, work through the JapanesePod101 informal series deliberately, and hold on to the inside-outside idea rather than the slider. When you catch yourself asking how much respect a situation deserves, replace it with a different question: which side of the line is this person on, right now, in this conversation. That question generalises. The slider does not.
If you want one rule to carry around, here it is. Let the other person come down first. If somebody your own age or younger drops into plain form with you, follow them. If they do not, stay where you are and be warm in other ways: your tone, what you talk about, how much you laugh. Warmth is not a grammatical feature and Japanese people are not waiting for you to conjugate your way into friendship.
One last thing, from my side of it
There is a moment I want to describe, because I do not think any product can teach it and I think it explains what you are actually working toward.
When somebody tells you you can speak casually with me, that is not an instruction. It is permission, and permission is not the same as a switch being flipped. The relationship still has to arrive at the point where plain form is what you would honestly say. If you flip immediately on being told to, it sounds like compliance rather than closeness, which is a strange thing to hear and hard to explain to the person doing it.
What actually happens between Japanese people is smaller and slower. One sentence comes out plain, usually late in an evening, usually because somebody was tired or surprised or laughing. The other person either follows or does not. Nobody remarks on it. A week later the register has moved and neither of you could say when.
That is the skill, and it is not a conjugation. It is reading a person accurately enough to know that the moment has arrived, which is the same skill you already have in your own language and have not yet mapped onto this one. Every product on this page can give you the forms. Bunpro can get them into your hands. JapanesePod101 can explain the system. The moment is yours, and you will get it wrong a few times, and being slightly too polite while you learn is the cheapest mistake available to you.
Take that deal. It is a much better one than it looks.