> ## Documentation Index > Fetch the complete documentation index at: https://docs.ton.org/llms.txt > Use this file to discover all available pages before exploring further. ## Submitting Feedback If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback: POST https://docs.ton.org/feedback ```json { "path": "/foundations/messages/internal", "feedback": "Description of the issue" } ``` Only submit feedback when you have something specific and actionable to report. # Internal messages Internal messages are the messages sent from a contract to an arbitrary account. They are the most common type of a message. ## After processing The contents of an internal message after it was processed are as follows: ```tlb theme={"theme":{"light":"github-light-default","dark":"dark-plus"},"languages":{"custom":["/resources/grammars/tolk.tmLanguage.json","/resources/grammars/tlb.tmLanguage.json","/resources/grammars/fift.tmLanguage.json","/resources/grammars/tasm.tmLanguage.json","/resources/grammars/func.tmLanguage.json"]}} int_msg_info$0 ihr_disabled:Bool bounce:Bool bounced:Bool src:MsgAddressInt dest:MsgAddressInt value:CurrencyCollection extra_flags:(VarUInteger 16) fwd_fee:Grams created_lt:uint64 created_at:uint32 = CommonMsgInfo; message$_ {X:Type} info:CommonMsgInfo init:(Maybe (Either StateInit ^StateInit)) body:(Either X ^X) = Message X; ``` * `ihr_disabled` — unused, always set to `true`. * `bounce` — whether the message is [bounceable](#bounces). * `bounced` — whether the message has been [bounced](#bounces). * `src` — address of the contract that sent the message. * `dest` — address of the account that received the message. * `value` — amount of Toncoin and extra-currency attached to the message. * `extra_flags` — used with the [new bounce format](#new-bounce-format). * `fwd_fee` — fee charged for forwarding the message. * `created_lt` — logical time when the message was created. * `created_at` — unix time when the message was created. ## Before processing When a contract sends a message, the requirements for the structure above are relaxed. ```tlb theme={"theme":{"light":"github-light-default","dark":"dark-plus"},"languages":{"custom":["/resources/grammars/tolk.tmLanguage.json","/resources/grammars/tlb.tmLanguage.json","/resources/grammars/fift.tmLanguage.json","/resources/grammars/tasm.tmLanguage.json","/resources/grammars/func.tmLanguage.json"]}} int_msg_info$0 ihr_disabled:Bool bounce:Bool bounced:Bool // NB! different type src:MsgAddress dest:MsgAddressInt value:CurrencyCollection extra_flags:(VarUInteger 16) fwd_fee:Grams created_lt:uint64 created_at:uint32 = CommonMsgInfoRelaxed; message$_ {X:Type} info:CommonMsgInfoRelaxed // NB! actually StateInitWithLibs init:(Maybe (Either StateInit ^StateInit)) body:(Either X ^X) = MessageRelaxed X; _ fixed_prefix_length:(Maybe (## 5)) special:(Maybe TickTock) code:(Maybe ^Cell) data:(Maybe ^Cell) library:(HashmapE 256 SimpleLib) = StateInitWithLibs; ``` The process of transforming the relaxed version of the structure into the strict version occurs in the action phase and is performed by the handler of [send message actions](/foundations/actions/send). This action rewrites [some fields](/foundations/actions/send#message-normalization) of the structure with correct values and validates the `StateInit` field against the `StateInitWithLibs` type. ## Deploy It is possible to simultaneously send both the payload in the `body` field and the `StateInit` in the `init` field to [initialized the contract](/foundations/messages/deploy) and process the payload in the same transaction. ## Message value The message may set `value` field that tells to transfer Toncoin and extra-currency to the recipient of the message. The actually transferred amount depends on the value of this field and a [send mode](/foundations/messages/modes). ## Bounces A bounce message is used to inform the sender that handling of their message failed. It is sent automatically to a sender when * there is enough Toncoin to send it left from handling the failed message, * and the message is bounceable, * and when either * a contract throws an error from the [compute phase](/foundations/phases#compute-phase) during message processing, and the state was not committed by [`COMMIT`](/tvm/instructions#f80f-commit) TVM instruction, * or an action fails in the [action phase](/foundations/phases#action-phase) with the `+16` flag enabled: [`SendBounceIfActionFail`](/foundations/messages/modes) in case of message sends or [`ReserveBounceIfActionFail`](/foundations/actions/reserve#modes) in case of reservations. ### Default bounce If the `bounce` flag is set to `true`, the message is bounceable. If the bounce conditions are met, the bounce message is produced from the failed message with the following transformation: * `src` and `dest` fields are swapped. * The `bounced` flag is set to `true` to tell it's the bounce message. * The `bounce` flag is set to `false` to prevent infinite loop of bouncing messages until no Toncoin is left to spend. * `body` is replaced with the concatenation of 32 bits equal to one (`0xffffffff`) and the first 256 bits of the old `body`. The new `body` is stored in the message in-place, with [`left`](https://github.com/ton-blockchain/ton/blob/master/crypto/block/block.tlb#L10) of the `Either`. This message is then sent to the `src` address of the original message. ### New bounce format The default bounce format has a flaw, that its `body` is too small to store even an internal address, and thus has limited usability for real-world applications. A new bounce format was introduced to address this issue. Using the `extra_flags` field, it is possible to change how the new `body` will be constructed. All other transformations remain the same. * If `(extra_flags & 1) = 1` the new bounce format is enabled. The bounced message now contains the root cell of the `body` of the failed message, with all the refs removed from it. * If `(extra_flags & 2) = 2` is *also* set, the bounced message contains the entire `body` of the original message, without removing any refs. All other bits in `extra_flags` are reserved for future use. When a message in new bounce format is bounced, the bounce message body has the following format (`new_bounce_body`): ```tlb theme={"theme":{"light":"github-light-default","dark":"dark-plus"},"languages":{"custom":["/resources/grammars/tolk.tmLanguage.json","/resources/grammars/tlb.tmLanguage.json","/resources/grammars/fift.tmLanguage.json","/resources/grammars/tasm.tmLanguage.json","/resources/grammars/func.tmLanguage.json"]}} _ value:CurrencyCollection created_lt:uint64 created_at:uint32 = NewBounceOriginalInfo; _ gas_used:uint32 vm_steps:uint32 = NewBounceComputePhaseInfo; // NB! 0xfffffffe is different from the old 0xffffffff new_bounce_body#fffffffe original_body:^Cell original_info:^NewBounceOriginalInfo bounced_by_phase:uint8 exit_code:int32 compute_phase:(Maybe NewBounceComputePhaseInfo) = NewBounceBody; ``` * `original_body` — the cell that contains the body of the original message. If `extra_flags & 2` then the whole body is returned; otherwise only the root without refs is included. * `original_info` — the value, lt, and Unix time of the original message. * `bounced_by_phase`: * `0` - compute phase was skipped. `exit_code` denotes the skip reason: * `exit_code = -1` — no state (an account is uninit or frozen, and no `StateInit` is present in the message). * `exit_code = -2` — bad state (an account is uninit or frozen, and `StateInit` in the message has the wrong hash). * `exit_code = -3` — no gas. * `exit_code = -4` — account is suspended. * `1` — compute phase failed. `exit_code` is the value from the compute phase. * `2` — action phase failed. `exit_code` is the value from the action phase. * `exit_code` — 32-bit exit code, see above. * `compute_phase` — exists if it was not skipped, i.e., when `bounced_by_phase` is not 0. * `gas_used` — same as `gas_used` of `TrComputePhase` of the transaction. * `vm_steps` — same as `vm_steps` of `TrComputePhase` of the transaction. The bounced message has the same 0th and 1st bits in `extra_flags` as the original message. The rest of the bits are set to zero.